Download 1. The table below refers to some disaccharides, their constituent

1.
The table below refers to some disaccharides, their constituent monomers and their roles in
living organisms.
Complete the table by writing in the appropriate word or words in the empty boxes.
Disaccharide
Constituent monomers
One role in living
organisms
Carbohydrate source in
mammalian milk
Lactose
Glucose + glucose
Form in which sugars
are transported in plants
(Total 5 marks)
2.
(a)
Explain what is meant by the primary structure of a protein molecule.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(b)
Explain the role of hydrogen bonding in maintaining the structure of a globular protein
such as insulin.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(3)
1
(c)
Describe how the structure of a fibrous protein, such as collagen, differs from the
structure of a globular protein.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(3)
(Total 8 marks)
3.
Read through the following account of the structure of deoxyribonucleic acid (DNA), then write
on the dotted lines the most appropriate word or words to complete the account.
DNA is a molecule consisting of a long chain of nucleotides, which are joined together
by................................... reactions. Each nucleotide in DNA consists of a
nitrogenous base, a phosphate group and ................................... .The
nitrogenous base may be adenine, guanine, cytosine or .................................... .
A molecule of DNA is made up of two polynucleotide chains coiled into a
................................... . The two chains are held together by
................................... bonds between the nitrogenous bases
(Total 5 marks)
2
4.
Read through the following passage about protein structure, then write on the dotted lines the
most appropriate word or words to complete the passage.
Proteins are composed of long chains of monomers called ...............................................,
which are linked together by ........................................................ bonds. These bonds are
formed by ..................................................... reactions between adjacent monomers. The
primary structure of a protein is the specific sequence of monomers in a polypeptide
chain and determines the secondary and tertiary protein structure. The secondary
structure of a protein may be a coil, known as an ...............................................................
which is held in shape by ............................................................. bonds between different
monomers in the chain.
(Total 5 marks)
5.
The diagram below shows the structure of a nucleotide.
A
B
(a)
C
Identify the parts labelled A, B and C in the diagram.
A ................................................................................................................................
B ................................................................................................................................
C ................................................................................................................................
(3)
3
(b)
The sequence of bases from part of a gene is shown below.
AGCCGTCCCGTC
Write out the sequence of bases on messenger RNA (mRNA) that would be coded for by
this part of the gene.
....................................................................................................................................
(2)
(c)
Describe what is meant by the semi-conservative replication of DNA.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(4)
(d)
A quantity of DNA was labelled with radioactive nitrogen. It was then allowed to
replicate three times, using non-radioactive nucleotides to synthesise the new DNA
strands. What proportion of the final mass of DNA would you expect to be radioactive?
Explain your answer.
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
(2)
4
(e)
In which stage of the cell cycle does replication of DNA take place?
...................................................................................................................................
(1)
(Total 12 marks)
6.
The table below refers to two disaccharides, sucrose and maltose. If the statement is correct,
place a tick ( ) in the appropriate box and if the statement is incorrect, place a cross ( ) in the
appropriate box.
Statement
Sucrose
Maltose
Contains glucose
Is a reducing sugar
Contains glycosidic bonds
Is transported in the phloem
of flowering plants
(Total 4 marks)
5
7.
Read through the following account of the properties of water, then write on the dotted lines the
most appropriate word or words to complete the account.
Water has the chemical formula ………………………………… . Water molecules are
described as ………………………………….. because they have a slight positive charge
at one end of the molecule and a slight negative charge at the other end. As a result,
individual molecules form ………………………………….. bonds with each other.
Water is an important ………………………………….. in living organisms because
most biochemical reactions take place in aqueous solution. Water also has a high
………………………………….., which means that its temperature remains relatively
stable despite large changes in the temperature of the surrounding environment.
(Total 5 marks)
8.
Explain what is meant by the following terms.
(a)
Semi-conservative replication of DNA
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
(3)
6
(b)
Tertiary structure of a protein
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
(3)
(Total 6 marks)
9.
Give an account of the structure and functions of lipids, including triglycerides and
phospholipids.
(Allow 3 lined pages)
(Total 10 marks)
10.
The table below refers to the structure of different types of nucleic acids. If the feature is
present, place a ( ) in the appropriate box and if the feature is absent place a cross ( ) in the
appropriate box.
Feature
DNA
mRNA
Cytosine present
Uracil present
Pentose sugar present
Is single stranded
(Total 4 marks)
7
11.
Read through the following passage about protein structure, then write on the dotted lines the
most appropriate word or words to complete the passage.
The tertiary structure of a protein depends on its primary and secondary structure.
The primary structure is the ………………………………….. of amino acids, which are
joined together by ………………………………….. bonds to form a chain. This type of
bond is formed when a ………………………………….. reaction takes place between
two amino acids.
The chain of amino acids may be folded into an alpha helix, held in shape by
………………………………….. bonds.
A number of different types of bonds hold the tertiary and quaternary structure
in shape. For example, the two peptide chains in insulin are held together
by ………………………………….. bonds which form between the
………………………………….. of certain amino acids.
(Total 6 marks)
8
12.
The diagram below summarises the steps involved in the semi-conservative replication of DNA.
Double strand of DNA
Step 1
Enzyme A
Two strands separated
Step 2
Complementary nucleotides line up against each strand
Step 3
Enzyme B
Nucleotides join to form two new polynucleotide chains
Step 4
Two identical DNA molecules formed
(a)
Describe how Enzyme A separates the two DNA strands in Step 1.
……………………………………………….………………………………………
……………………………………………….………………………………………
(1)
(b)
In Step 3 the individual nueleotides are joined up to form a polynucleotide chain by
Enzyme B.
Name the type of reaction that Enzyme B catalyses.
……………………………………………….………………………………………
(1)
(c)
Give the phase of the cell cycle during which DNA replication occurs.
……………………………………………….………………………………………
(1)
(Total 3 marks)
9
13.
The diagram below shows the structure of the cell surface membrane.
Carbohydrate
Proteins
Glycoprotein
(a)
The cell surface membrane is composed of a phospholipid bilayer. Explain why tile
phospholipids in the bilayer are arranged with the fatty acid tails pointing inwards and the
phosphate heads outwards.
……………………………………………….………………………………………
……………………………………………….………………………………………
……………………………………………….………………………………………
……………………………………………….………………………………………
……………………………………………….………………………………………
……………………………………………….………………………………………
(3)
(b)
The diagram has been magnified three million (3 × 106) times. Calculate the width of
the cell surface membrane in tin (micrometres). Show your working.
Answer ………………………… µm
(3)
(c)
State one function of each of the following components of the cell surface membrane.
Carbohydrate ………………………………………………………………………..
Protein ………………………………………………………………………………
(2)
(Total 8 marks)
13
14.
The table below refers to the formula and structure of some biological molecules.
Complete the table by writing in the name, the formula or the structure of the molecule where
appropriate in the empty boxes.
Name
Formula
Water
H2 O
Structure
NH2RCHCOOH
Fatty acid
H
H
H
H
H
H
C
C
C
C
C
H
H
H
H
H
O
C
OH
CH 2 OH
C
H
C
HO
O
H
OH H
C
C
H
OH
H
C
OH
(Total 6 marks)
17
15.
The diagram below shows the structure of two fatty acids.
O
C
A
O
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
H
H
H
H
H
H
H
H
O
B
C
O
H
H
C
H
C
C
H
H
(a)
Give the name of the molecule to which three fatty acids are bonded to form a
triglyceride lipid.
.....................................................................................................................................
(1)
(b)
(i)
Name the type of fatty acid labelled B.
...........................................................................................................................
(1)
(ii)
Describe one way in which the physical properties of a triglyceride composed of
fatty acids of type B will differ from a triglyceride of similar molecular size
composed of fatty acids of type A.
...........................................................................................................................
...........................................................................................................................
(1)
18
(c)
Draw a diagram to show the arrangement of phospholipid molecules in a unit (cell)
membrane.
(2)
(Total 5 marks)
16.
The diagram below shows the structure of a triglyceride molecule.
O
H
H
C
O
C
O
H
C
O
C
O
H
C
O
C
H
A
(a)
(i)
Name the part of the molecule labelled A.
...............................................................................................................................................
(1)
(ii)
Name the type of bond formed between part A and a fatty acid.
...............................................................................................................................................
(1)
19
(b)
Stearic acid and oleic acid are both examples of fatty acids. Each has a hydrocarbon chain
containing 17 carbon atoms. Stearic acid is a saturated fatty acid but oleic acid is an
unsaturated fatty acid.
Give two ways in which the structure of a stearic acid molecule differs from the structure
of an oleic acid molecule.
1 ............................................................................................................................................
...............................................................................................................................................
2 ............................................................................................................................................
...............................................................................................................................................
(2)
(c)
Describe two functions of lipids in animals.
1 ............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
2 ............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
(4)
(Total 8 marks)
20
17.
The diagram below shows a stage in the process of translation during protein synthesis. This
process is occurring on a ribosome.
Amino acids
Ribosome
Amino acid
4
tRNA molecule
1
3
2
Anticodon
GU A
GGU
AAA
G C C AC G
GG
U
Part of a messenger
RNA molecule
(a)
Describe the structure of a ribosome.
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
(2)
22
(b)
The table below shows the anticodons of some tRNA molecules and the specific amino
acids that each one carries.
tRNA anticodon
Amino acid
GGU
Proline
CCA
Glycine
AAA
Phenylalanine
CGA
Alanine
ACC
Tryptophan
UUU
Lysine
Using the information in the table, identify amino acids 2 and 3 shown in the diagram on
the previous page.
Amino acid 2 .........................................................................................................................
Amino acid 3 .........................................................................................................................
(2)
(c)
During translation, amino acids are linked by a peptide bond.
(i)
Draw a diagram to show two amino acids linked by a peptide bond.
(3)
23
(ii)
Name the type of reaction that occurs during the formation of a peptide bond.
.....................................................................................................................................
(1)
(Total 8 marks)
18.
Carbohydrates are used as a source of energy. Excess carbohydrate can be stored as glycogen in
animal cells.
(a)
Give two reasons why glycogen is used as a storage molecule.
1 ..................................................................................................................................
2 ..................................................................................................................................
(2)
(b)
The diagram below shows a molecule of maltose.
(i)
Complete the diagrams below to show the two glucose molecules that will result
when this maltose molecule is broken down.
(2)
24
(ii)
Name the type of chemical reaction that occurs when maltose breaks down.
...........................................................................................................................
(1)
(Total 5 marks)
19.
The diagram below shows part of a DNA molecule.
Y
Z
X
Adenine
W
(a)
(i)
Cytosine
Name the parts of the molecule represented by each of the following letters.
W ......................................................................................................................
X ......................................................................................................................
Y ......................................................................................................................
Z ......................................................................................................................
(4)
(ii)
Name the type of bond that holds the two strands of DNA together.
...........................................................................................................................
(1)
25
(b)
The table below shows the amino acids coded by mRNA codons.
Second base
C
A
G
UUU
U UUC
UUA
UUG
Phenylalanine
Phenylalanine
Leucine
Leucine
UCU
UCC
UCA
UCG
Serine
Serine
Serine
Serine
UAU
UAC
UAA
UAG
Tyrosine
Tyrosine
Stop
Stop
UGU
UGC
UGA
UGG
Cysteine
Cysteine
Stop
Tryptophan
U
C
A
G
CUU
CUC
C CUA
CUG
Leucine
Leucine
Leucine
Leucine
CCU
CCC
CCA
CCG
Proline
Proline
Proline
Proline
CAU
CAC
CAA
CAG
Histidine
Histidine
Glutamine
Glutamine
CGU
CGC
CGA
CGG
Arginine
Arginine
Arginine
Arginine
U
C
A
G
AUU
A AUC
AUA
AUG
Isoleucine
Isoleucine
Isoleucine
Methionine
ACU
ACC
ACA
ACG
Threonine
Threonine
Threonine
Threonine
AAU
AAC
AAA
AAG
Asparagine
Asparagine
Lysine
Lysine
AGU
AGC
AGA
AGG
Serine
Serine
Arginine
Arginine
U
C
A
G
GUU
GUC
G GUA
GUG
Valine
Valine
Valine
Valine
GCU
GCC
GCA
GCG
Alanine
Alanine
Alanine
Alanine
GAU
GAC
GAA
GAG
Aspartic acid
Aspartic acid
Glutamic acid
Glutamic acid
GGU
GGC
GGA
GGG
Glycine
Glycine
Glycine
Glycine
U
C
A
G
(i)
Third base
First base
U
Name the process by which mRNA is formed in the nucleus.
...........................................................................................................................
(1)
(ii)
Reading from left to right, what is the sequence of amino acids coded by the
following length of mRNA?
G
A
U
C
G
U
U
G
U
A
A
G
...........................................................................................................................
(1)
26
(iii)
A mutation occurred so that the base cytosine was replaced by guanine in this
mRNA. Using the information in the table, explain why this mutation could affect
the tertiary structure of the protein formed from this mRNA.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(Total 10 marks)
20.
The diagram below shows four molecules of water.
H
H
O
H
H O
H
O
A
(a)
H
H
H
O
Name the type of bond labelled A on the diagram.
……………………………………………………………………………………………
(1)
(b)
Explain why water molecules are described as dipolar.
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
(2)
27
(c)
One of the properties of water is that it has a high specific heat capacity. Explain why this
property is important for organisms that live in water.
……………………………………………………………………………………………
……………………………………………………………………………………………
(2)
(Total 5 marks)
21.
Protein synthesis involves transcription and translation.
(a)
(i)
Where does transcription take place in a eukaryotic cell?
………………………………………………………………………………………
(1)
(ii)
Name the type of chemical reaction that occurs when a strand of messenger RNA is
formed from individual nucleotides.
………………………………………………………………………………………
(1)
(b)
The diagram below shows part of a messenger RNA (mRNA) molecule.
C
(i)
G
A
A
C
C
G
C
C
C
G
A
A
U
C
A
C
C
What is the maximum number of amino acids coded for by this strand of mRNA?
.....................................................................................................................................
(1)
(ii)
Complete the diagram below to show the sequence of bases on the strand of DNA
that coded for this mRNA.
(2)
28
(c)
A strand of mRNA was found to have 53 codons but the protein produced from it
contained only 51 amino acids. Suggest two reasons for this difference.
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
(2)
(d)
Describe the process of translation.
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
(5)
(Total 12 marks)
29
22.
(a)
DNA is replicated by a process called semi-conservative replication. Explain what is
meant by the term semi-conservative replication.
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
……………………………………………………………………………………………
(4)
(b)
When bacteria grow and reproduce they need a nitrogen source. The nitrogen becomes
part of their DNA.
Bacteria were placed in a culture medium containing a heavy form of nitrogen. The
bacteria were grown and allowed to reproduce for several generations until all the
nitrogen in their DNA was heavy nitrogen.
The bacteria were removed, washed thoroughly and then divided into five batches
labelled A, B, C, D and E. They were then placed in fresh culture medium and allowed to
grow for different periods of time.
Batch A was placed into fresh culture medium containing heavy nitrogen, and left for
four generations. The other four batches were placed into fresh culture medium
containing light nitrogen and left for different periods of time.
30
The treatments are shown in the table below.
Batch
A
B
C
D
E
First treatment
All
grown
in
heavy
nitrogen
Second treatment
Grown in heavy nitrogen for four generations
Grown in light nitrogen for one generation
Grown in light nitrogen for two generations
Grown in light nitrogen for three generations
Grown in light nitrogen for four generations
The DNA from the five batches of bacteria was then removed, placed on separating
solutions and centrifuged (spun). The mass of DNA added to each separating solution
was the same.
DNA containing different proportions of heavy and light nitrogen can be seen as separate
bands after centrifugation. The heavier molecules are lower down in the separating
solution than the lighter molecules. The wide bands contain more molecules than the
narrow bands.
Figure 1 shows an example of the results of centrifuging a mixture of heavy and light
DNA.
Figure 1
31
Figure 2 shows the results for the batches A, B, C and D.
Figure 2
(i)
Explain why the DNA from batch B is higher up in the separating solution than the
DNA from batch A.
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
(2)
(ii)
Explain the results for batch C.
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
………………………………………………………………………………………
(3)
32
(iii)
On Figure 2, draw in the bands you would expect to see for the DNA separated
from the bacteria grown in batch E.
(2)
(Total 11 marks)
23.
The diagram below shows the structure of a human insulin molecule. Each circle
represents one amino acid.
S
S
A chain
Gly Ile Val Glu Glu Cys Cys Thr Ser Ile Cys Ser Leu Tyr Glu Leu Glu Asn Tyr Cys Asn
S
S
S
S
Phe Val Asn Glu His Leu Cys Gly Ser His Leu Val Glu Ala Leu Tyr Leu Val Cys Gly Glu Arg Gly Phe Phe Tyr Thr Pro Lys Thr
B chain
Insulin is a protein that has a tertiary structure and a quaternary structure.
(a)
(i)
Name two types of bond that help to maintain the tertiary structure.
1. ............................................................................................................................
2. ............................................................................................................................
(2)
(ii)
What evidence is there in the diagram that insulin has a quaternary structure?
...............................................................................................................................
...............................................................................................................................
(1)
(b)
(i)
All human insulin molecules have the same primary structure. Explain what is
meant by primary structure.
...............................................................................................................................
...............................................................................................................................
(1)
33
(ii)
When insulin molecules are formed they fold into a specific shape. Explain why all
human insulin molecules fold into the same shape.
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
(2)
(Total 6 marks)
24.
(a)
The statements in the table below refer to three biological molecules.
If a statement is correct place a tick ( ) in the appropriate box and if a statement is
incorrect place a cross ( ) in the appropriate box. Four boxes have already been
completed for you.
Statement
Starch
Glycogen
Monosaccharide
Is a polymer
Glycosidic
bonds are
present
Is an energy
store in
animal cells
Has high
solubility in
water
(4)
(b)
The diagram below represents a polypeptide consisting of amino acids.
State the minimum number of bases needed to code for this polypeptide along a strand of
mRNA.
.....................................................................................................................................
(1)
34
(c)
Describe the key stages involved in protein synthesis, from the genetic code in the
nucleus to the sequence of amino acids being assembled at the ribosome.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(d)
Explain how the sequence of amino acids determines the shape of a protein.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 12 marks)
25.
Carbohydrates and lipids are both sources of energy in the diet. A high carbohydrate intake
stimulates the production of fatty acids. Eating excessive amounts of carbohydrates can lead to
obesity.
35
(a)
(i)
The diagram below illustrates part of the structure of a fatty acid with the formula
C15H31COOH. Complete the diagram of the molecule.
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H—C— C— C— C— C— C— C— C— C— C— C— C— C— C— C—
H
(ii)
H
H
H
H
H
H
H
H
H
H
H
H
H
(2)
H
State whether this fatty acid is saturated or unsaturated. Give a reason for your
answer.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
(i)
Explain what is meant by the term risk factor.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Explain how obesity increases the risk of developing coronary heart disease.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
36
(c)
Energy drinks containing glucose provide a concentrated source of energy that is
particularly valuable during exercise.
Explain why glucose can provide a quick energy boost during exercise.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(3)
(Total 11 marks)
26.
(a)
The table below refers to the composition of the disaccharides sucrose, maltose and
lactose. Place a tick ( ) in the appropriate box or boxes to indicate clearly the
monosaccharide or monosaccharides that make up each disaccharide.
Monosaccharides
Disaccharide
Galactose
Glucose
Fructose
Sucrose
Maltose
Lactose
(3)
(b)
Name the bond that joins two monosaccharides in a disaccharide.
.......................................................................................................................................
(1)
(Total 4 marks)
37
27.
Read through the following passage about protein structure, then write on the dotted lines the
most appropriate word or words to complete the passage.
All amino acids contain the elements carbon, hydrogen, oxygen and
................................................ The primary structure of a protein is formed when amino
acids are joined together by ............................................... bonds. Chains of amino acids
may then form a secondary structure such as a spiral shape called the
..............................................., which is maintained by ...............................................
bonding. The tertiary structure of a protein is maintained by bonding between the
............................................... of amino acids.
(Total 5 marks)
28.
Sucrose is a disaccharide made up from one molecule of glucose bonded to one molecule of
fructose. Sucrose needs to be digested by the enzyme sucrase before it can be absorbed into the
blood.
(a)
The diagram below illustrates how the enzyme sucrase may catalyse the breakdown of
sucrose into glucose and fructose.
Sucrose
R
Glucose
Fructose
Q
Sucrase
Use the diagram to identify:
(i)
reactant Q
...........................................................................................................................
(1)
38
(ii)
the region labelled R
...........................................................................................................................
(1)
(iii)
the name of the bond between the glucose and fructose molecules that is broken by
the reaction shown in the diagram.
...........................................................................................................................
(1)
(b)
(i)
Explain why sucrase will digest sucrose and not any other disaccharide.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
Name and describe one way that glucose is absorbed across cell membranes.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 8 marks)
29.
(a)
Maltose is a disaccharide formed by a reaction between two alpha (α) glucose molecules.
Complete the word equation below, which represents this reaction.
α-glucose
+
α-glucose
–→
maltose
+
.............................................
(1)
39
(b)
Draw the structure of a molecule of alpha glucose.
(3)
(c)
Describe a function of maltose.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
40
30.
(a)
In the space below draw a diagram to show two mononucleotides joined together in a
single strand of DNA (polynucleotide). Use the symbols shown for each component in
your diagram.
Phosphate group:
Deoxyribose:
Base:
Covalent bonds:
(3)
41
(b)
Describe how two strands of DNA are joined to form a DNA molecule and how this
molecule is organised in a chromosome.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(c)
The table below shows the percentage content of one of the four bases in a molecule
of DNA.
Name of base
Percentage content
Adenine
14
Cytosine
Guanine
Thymine
(i)
Use the information in the table to calculate the percentage content of the other
three bases in this molecule of DNA. Write your answers in the table.
(3)
42
(ii)
State what percentage of the bases in this molecule of DNA are purines.
...........................................................................................................................
(1)
(Total 12 marks)
31.
The table below summarises the structure of some of the main chemical compounds found in
living organisms.
(a)
Complete the empty boxes in the table.
Chemical
Compound
One example of the
chemical compound
found in living organisms
Subunits of
the chemical
Elements
contained in
the chemical
Polysaccharide
Protein
Enzyme
C, H, O, N, S
Lipid
Phospholipid
C, H, O
Nucleic acid
Nucleotide
(7)
(b)
State one difference between a saturated and an unsaturated fat (lipid).
.....................................................................................................................................
.....................................................................................................................................
(1)
43
(c)
Draw a labelled diagram to show the arrangement of phospholipids and proteins in the
fluid mosaic model of a cell membrane.
(3)
(Total 11 marks)
32.
The table below shows population statistics and deaths from coronary heart disease (CHD) for
males and females in England during a two year period.
Number in the population
Number dying from CHD
Males
23 922 144
33 879
Females
25 216 687
9 016
(a)
(i)
For this two year period, calculate the percentage risk of a male dying from CHD.
Show your working.
(1)
(ii)
Use the data in the table above to calculate how many times females are less likely
to die from CHD than males.
(1)
44
(b)
Body Mass Index (BMI) can be used to indicate whether a person is overweight. The
chart below shows the effect of having a high BMI on the risk of dying of CHD when
compared with a control group with a normal BMI of 20. A person with a BMI of 30 is
obese.
50
Increase in
risk of death
due to
CHD /%
40
30
20
10
0
20
25
30
35
Body Mass Index (BMI)
(i)
Describe the trend shown in the chart.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(ii)
Give the formula used to calculate BMI.
(1)
45
(iii)
Explain why people who are overweight are more likely to die from CHD.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(Total 8 marks)
33.
The function of a protein depends on its shape.
(a)
(i)
Explain what is meant by the primary structure of a protein.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Explain how the primary structure of a protein is important in determining its
shape.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
46
(b)
Explain why most enzymes are specific to only one substrate.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(c)
Describe the process that converts a genetic sequence on messenger RNA into the
primary sequence of a protein.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(4)
(Total 9 marks)
47
34.
The table below refers to the structure of DNA and RNA. If the statement is correct, place a tick
( ) in the appropriate box and if the statement is incorrect, place a cross ( ) in the appropriate
box.
Statement
DNA
mRNA
Is double stranded
Contains the bases adenine and uracil
Contains a pentose sugar
Contains phosphodiester bonds
(Total 4 marks)
35.
Read through the following account of the roles of lipids in living organisms, then write on the
dotted lines the most appropriate word or words to complete the account.
Lipids have many important roles in living organisms. They are found as small droplets
of oil in many cells where they act as an ....................................................
Fats are found deposited beneath the skin of animals where they provide
.................................................... and .................................................... .
In plants, waxes are found on the upper surface of leaves where they act as a
.................................................... layer.
(Total 4 marks)
48
36.
(a)
The diagram below shows the structures of two amino acids, alanine and serine.
H
H
N
H
C
O
N
C
CH 3
H
H
OH
H
C
CH 2
O
C
OH
OH
Alanine
Serine
In the space below, draw a diagram to show a dipeptide formed when these two
molecules bond together.
(2)
49
(b)
Computer-generated models were used to measure the length in nanometres (nm) of a
polypeptide containing a large number of amino acids. Measurements were made of the
primary and secondary structure of the polypeptide. The models were used to measure the
length of the polypeptide at 25 °C and at 55 °C. The results are shown in the table below.
Length of polypeptide/nm
Structure of polypeptide
at 25 °C
at 55 °C
Primary
505
505
Secondary
48
70
(i)
Explain what is meant by the term secondary structure of a protein.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(ii)
Compare the results obtained at 25 °C with those obtained at 55 °C.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
50
(iii)
Suggest why the increase in temperature has this effect on the length of the
secondary structure of the polypeptide.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 8 marks)
37.
The diagram below shows part of a starch molecule.
(a)
(i)
Name the type of chemical reaction that joins monosaccharides together to form a
starch molecule.
...........................................................................................................................
(1)
(ii)
Name the type of chemical bond formed during this reaction.
...........................................................................................................................
(1)
(iii)
State what other molecule is produced in this reaction.
...........................................................................................................................
(1)
51
(b)
Starch and glycogen are both storage molecules in cells.
(i)
Explain two ways in which the structure of these molecules makes them suitable
for their role as storage molecules.
1 ........................................................................................................................
...........................................................................................................................
2 ........................................................................................................................
...........................................................................................................................
(2)
(ii)
Describe one structural difference between starch and glycogen.
...........................................................................................................................
...........................................................................................................................
(1)
(Total 6 marks)
38.
The diagram below shows the pairing between two bases in a DNA molecule.
Thymine
CH 3
H
H
N
C
N
C
H
O
N
C
N
H
C
N
C
C
N
C
C
C
N
H
Deoxyribose
O
H
Deoxyribose
(a)
(i)
Name the base which pairs with thymine.
...........................................................................................................................
(1)
52
(ii)
Name the base which replaces thymine in RNA.
...........................................................................................................................
(1)
(iii)
Apart from other bases, name one chemical group present in DNA not shown on
the diagram.
...........................................................................................................................
(1)
(b)
Describe two structural features of DNA which give it the ability to replicate.
1 ..................................................................................................................................
.....................................................................................................................................
2 ..................................................................................................................................
.....................................................................................................................................
(2)
(c)
Give two differences between the processes of DNA replication and transcription.
1 ..................................................................................................................................
.....................................................................................................................................
2 ..................................................................................................................................
.....................................................................................................................................
(2)
(Total 7 marks)
53
39.
Proteins are chains of amino acids and have a wide range of functions in living organisms.
(a)
(i)
The diagram below shows part of the general structure of two different amino
acids.
Complete the diagram to show how these two amino acids can be joined together.
H
R
N—C—
H
H
R
O
—C—C
H
OH
(1)
(ii)
Name the bond that is formed between the two amino acids.
...........................................................................................................................
(1)
(b)
Explain how the specific sequence of amino acids in a protein determines its threedimensional structure.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
54
(c)
Enzymes are proteins that speed up chemical reactions within living organisms. The
graph below shows the effect of changing enzyme concentration on the rate of reaction.
Rate of
reaction
X
Enzyme concentration
(i)
Explain why increasing the enzyme concentration above point X on the graph does
not increase the rate of the reaction further.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
55
(ii)
Outline the practical procedures that could have been used to obtain the results
shown on the graph.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(4)
(Total 10 marks)
40.
Read through the following passage about water, then write on the dotted lines the most
appropriate word or words to complete the passage.
A water molecule consists of two hydrogen atoms and one oxygen atom held
together by ........................................ bonds. There is an unequal distribution of charge
over the molecule. This is called a ........................................ and results in water being a
good ........................................ for many substances such as sodium ions.
Bonds called ........................................ bonds form between water molecules. As a result
water has a high ................................................................ meaning that a lot of
energy is needed to cause a small rise in temperature.
(Total 5 marks)
56
41.
(a)
The diagram below represents a transfer RNA (tRNA) molecule.
X
A
C
C
Y
A G U
(i)
Name the type of bond labelled Y.
...........................................................................................................................
(1)
(ii)
Name the molecule that is attached to position X during protein synthesis.
...........................................................................................................................
(1)
57
(iii)
Explain the meaning of the term anticodon.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
State two ways in which the structure of a tRNA molecule differs from the structure of a
messenger RNA (mRNA) molecule.
1 ..................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
2 ..................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 6 marks)
58
42.
(a)
DNA in eukaryotic organisms is a double helix. Bases on one strand bond to bases on the
second strand to form base pairs. During protein synthesis, one strand of DNA (the
coding strand) acts as a template to make mRNA. The second strand is known as the noncoding strand.
The base sequence of a small section of the coding strand of a DNA molecule is shown
below.
AGACTTGCAACTTGACATGTA
(i)
How many codons are shown in this sequence?
...........................................................................................................................
(1)
(ii)
Give the sequence of the first five bases that would be present in each of the
following:
1.
the mRNA molecule transcribed from this DNA strand
...........................................................................................................................
2.
the non-coding strand of this DNA
...........................................................................................................................
(2)
59
(b)
A sample of DNA from a locust was analysed to determine the percentage of each base
present. The percentage of adenine was found to be 29.4%.
Calculate the percentage of cytosine in this sample. Show your working and give an
explanation for your answer.
Percentage of cytosine = .............................................................................................
Explanation: ................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(Total 8 marks)
60
43.
Proteins have a wide range of functions in living organisms. The function of a protein is related
to its precise three dimensional shape, which is determined by its specific sequence of amino
acids. The diagram below shows a model of a typical protein molecule.
(a)
(i)
Complete the diagram below to give the structure of the amino acid glycine.
H
C
H
(2)
61
(ii)
Explain how a specific sequence of amino acids can form the precise three
dimensional shape of a protein molecule.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(b)
The following DNA base sequence codes for part of a protein molecule.
TACGGTATGCCAACCTTC
(i)
State the number of amino acids coded by this section of DNA.
...........................................................................................................................
(1)
(ii)
Name the process involved in converting a base sequence of DNA into a base
sequence of messenger RNA (mRNA).
...........................................................................................................................
(1)
(iii)
Give the complementary mRNA sequence to the DNA sequence above.
...........................................................................................................................
(2)
(Total 9 marks)
62
44.
(a)
The following table contains some statements about the properties of polysaccharides,
lipids and proteins. Complete the table by placing a if a statement is correct and a
if
it is incorrect.
Polysaccharides
Lipids
Proteins
Are polymers
Have ester bonds
Contain carbon, hydrogen,
oxygen and nitrogen
Form components making
up the structure of cell
membranes
(6)
(b)
Give one difference between the following pairs of molecules:
(i)
Saturated and unsaturated lipids
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(ii)
Glycogen and starch
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 8 marks)
63
45.
Read through the following passage about lipids, then write on the dotted lines the most
appropriate word or words to complete the passage.
Lipids contain the elements hydrogen, carbon and oxygen joined together
by ............................................... bonds.
Triglycerides are lipids that consist of three ............................................... molecules
joined to a ............................................... molecule. These molecules are joined together
by a chemical process called a ............................................... reaction.
Triglycerides that have double bonds between carbon atoms are known
as ............................................... triglycerides.
(Total 5 marks)
46.
Adipose tissue contains stored triglycerides. Describe the structure of a triglyceride.
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
...............................................................................................................................................
(Total 3 marks)
64
47.
(a)
The diagram below shows the structure of a triglyceride.
Ch2 O
Bond A
CHO
CH2 O
O
C
O
C
O
C
triglyceride
(i)
Name Bond A on the diagram.
...........................................................................................................................
(1)
(ii)
Name the type of reaction that will break down the triglyceride into its constituent
parts during digestion by lipase enzymes.
...........................................................................................................................
(1)
(iii)
Name two products formed when triglycerides are completely digested.
1 ........................................................................................................................
2 ........................................................................................................................
(2)
(iv)
Some triglycerides have several double bonds (C C), others have none.
Describe one way in which the physical property of triglycerides which include
several double bonds will differ from triglycerides which have no double bonds.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
65
(b)
Lipids in membranes have an additional chemical group attached.
(i)
Name the chemical group which is added to the lipids in membranes.
...........................................................................................................................
(1)
(ii)
Explain how adding this extra chemical group allows the formation of a cell
membrane.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 8 marks)
48.
The diagram below illustrates part of a glycogen molecule.
CH2OH
CH2OH
C
H
C
HO
(a)
O H
H
OH
H
C
C
H
OH
H C
C
C
O
CH2OH
O H
H
OH
H
C
C
H
OH
H C
C
C
O
CH2OH
O H
H
OH
H
C
C
H
OH
H C
C
C
O
CH2OH
O H
H
OH
H
C
C
H
OH
H C
C
C
O
CH2OH
O H
H
OH
H
C
C
H
OH
H C
C
C
O
O
H
OH
H
C
C
H
OH
H
C
OH
State the role of glycogen in the human body.
.....................................................................................................................................
(1)
(b)
An enzyme is used to break the bonds holding the monomers (glucose molecules)
together.
(i)
In the space below draw one of the monomers that would result from this reaction.
66
(2)
(ii)
Explain why this enzyme will not break the bonds in a protein molecule.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
67
(c)
Explain the advantages, to living organisms, of using enzymes in biological reactions.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(Total 8 marks)
49.
(a)
Insulin and collagen are both proteins that have a primary structure made up of amino
acids joined together by peptide bonds.
(i)
Explain what is meant by the term primary structure of a protein.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Name the type of reaction that occurs when a peptide bond is broken causing a
dipeptide to split into two amino acids.
...........................................................................................................................
(1)
68
(b)
Insulin and collagen both contain the amino acids glycine and serine. The diagram below
shows a dipeptide formed from these two amino acids. Complete the diagram to show the
structure of serine when the peptide bond breaks.
H
H
O
H H
O
N—C—C—N—C—C
H
OH
H
CH2
OH
H
H
O
N—C—C
+
H
OH
H
Glycine
Serine
(1)
(Total 3 marks)
50.
(a)
The diagram below shows the structure of a mononucleotide from a DNA molecule.
A
B
Name the parts of the mononucleotide labelled A and B.
A ..............................................
B ..............................................
(1)
69
(b)
The table below shows the percentage of different bases present in the DNA from two
organisms.
Percentage of each base present
Organism
Yeast
Cow
(i)
Adenine
Guanine
Thymine
Cytosine
31
19
31
19
29
Complete the table to show the percentage of adenine, guanine and cytosine in the
DNA of a cow.
(1)
(ii)
Explain how you worked out the percentage of guanine present in the DNA of a
cow.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
70
(c)
DNA and messenger RNA (mRNA) have different properties. DNA is very stable but
mRNA breaks down quickly and most of it will be broken down within a day of it being
produced. Suggest why it is important for DNA to be more stable than mRNA.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(2)
(d)
Protein synthesis involves transcription and translation. Describe the process of
transcription.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(Total 12 marks)
71
51.
(a)
Name a component of DNA that contains nitrogen.
.....................................................................................................................................
(1)
(b)
When bacteria are grown in conditions containing a heavy form of nitrogen, they will
incorporate the heavy nitrogen into their DNA each time DNA replication occurs.
After many replications in these conditions, all the nitrogen in the bacterial DNA will be
of the heavy form.
If the bacteria are then switched to conditions containing a light form of nitrogen, this
will become incorporated each time DNA replication occurs.
The diagram below shows the changes in the DNA composition, over two DNA
replications, after the bacteria have been transferred from conditions containing heavy
nitrogen to conditions containing light nitrogen.
Complete the diagram to show the DNA composition in the third generation.
KEY
= Heavy nitrogen
= Light nitrogen
......................................................................................................................................................
DNA before
replication in light
nitrogen conditions
......................................................................................................................................................
DNA after the first
replication in light
nitrogen conditions
......................................................................................................................................................
DNA after the second
replication in light
nitrogen conditions
......................................................................................................................................................
DNA after the third
replication in light
nitrogen conditions
......................................................................................................................................................
(2)
72
(c)
Name an enzyme involved in DNA replication.
.....................................................................................................................................
(1)
(d)
The table below shows nine bases from a DNA template strand. Complete the table by
giving the corresponding bases on the complementary DNA strand.
DNA template strand
A
G
C
T
T
A
C
C
A
Complementary DNA
strand
(1)
(e)
Genetic disorders, such as cystic fibrosis, are caused by mutations in the sequence of
bases found in DNA.
Explain how a gene mutation may result in a protein that does not function normally.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
(5)
(Total 10 marks)
73
52.
Read through the following account on lipids, then write on the dotted lines the most
appropriate word or words to complete the account.
Lipids are insoluble in water because they are ......................................................
A triglyceride is one type of lipid. A triglyceride consists of one
.................................................... molecule with three .....................................................
molecules joined to it by ..................................................... bonds. Triglycerides
have important roles in living organisms, including waterproofing and
......................................................
(Total 5 marks)
53.
Lactose is a sugar found in human milk.
(a)
Lactose is a disaccharide that can be hydrolysed to its two monosaccharides, galactose
and glucose.
(i)
The diagram below shows lactose being hydrolysed. Complete the diagram by
drawing the missing components of the monosaccharide galactose in the left-hand
box and the monosaccharide glucose in the right-hand box.
Lactose
CH 2 OH
HO
CH 2 OH
O
H
H
O
H
H
O
H
OH
H
H
OH
CH 2 OH
H
OH
H
H
OH
OH
CH 2 OH
O
Galactose
O
Glucose
(2)
74
(ii)
Explain the term hydrolysis.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
Galactosaemia is a rare and potentially serious inherited condition. It is caused by a
recessive allele that reduces the ability of the body to break down galactose.
A couple is expecting a second child. Neither parent has galactosaemia but their first
child does have galactosaemia.
(i)
Using the symbols G and g, complete the genetic diagram below to show the
probability of the couple’s second child not having galactosaemia.
Parents’ genotypes ..........................................
..........................................
Parents’ gametes
Possible genotypes
of second child
..................
..................
..................
..................
Probability of their second child not having galactosaemia .............................
(3)
75
(ii)
The couple wanted confirmation that their second unborn child did not have
galactosaemia. To do this, fetal cells were taken, the DNA extracted and the alleles
associated with galactosaemia were sequenced.
A mutation was found in one of these alleles but the protein produced by this allele
was the same as the protein produced by the normal allele. The couple were told
this could be explained by the degenerate nature of the genetic code.
Explain how the degenerate nature of the genetic code could allow the mutated
allele to produce the same protein as a normal allele.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
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(2)
(iii)
Outline the ethical issues related to genetic screening of a fetus for inherited
disorders such as galactosaemia.
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(3)
(Total 12 marks)
54.
Carbohydrates are compounds that include monosaccharides, disaccharides and
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polysaccharides.
(a)
(i)
The table below lists some features of four carbohydrates.
Put a cross in the box to indicate that the feature is present in the carbohydrate.
The first row has been done for you.
Feature
Glucose
Glycogen
Maltose
Starch
1–4 glycosidic bonds present
1–6 glycosidic bonds present
Made up of many monomers
(4)
(ii)
Name the disaccharide made up of α-glucose and galactose.
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(1)
(iii)
The diagram below shows a disaccharide molecule.
CH2 OH
CH 2 OH
O H
H
H
H
OH
O OH
H
OH
H
H
O
HO
H
OH
H
H
OH
Draw the molecules resulting when this disaccharide molecule is split into its two
component monosaccharides.
(2)
(iv)
Name this type of reaction.
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(1)
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(b)
Explain the advantages of glycogen as an energy storage molecule in the human body.
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(3)
(Total 11 marks)
78