Download Higher Human Biology Unit 1: Human Cells Homework Questions

Calderglen High School
Higher Human Biology
Unit 1: Human Cells
Homework Questions
Contents
Page
Sub-Topic 1: Differentiation and stem cells
3-5
Sub-Topic 2: DNA and its replication
6-10
Sub-Topic 3: RNA, transcription and translation
11-19
Sub Topic 4: Proteins, mutations and genetic disorders
20-21
Sub topic 5: Human Genomics
22-24
Sub topic 6: Metabolism and Enzymes
26-29
Sub topic 7: Cellular respiration
30-39
2
Sub topic 1: Differentiation and stem cells
5. Which of the following statements regarding
1. Which of the following is not a use of stem cells?
A
Skin grafts
B
Drug testing
C
IVF treatment
D
Bone marrow transplant
stem cells is TRUE?
A Stem cells are specialised cells that
continue to divide.
B Stem cells cannot differentiate into
specialised cells
C Stem cells are unspecialised cells that
can differentiate into specialised cells.
2. Which line in the table below describes correctly cell
division in a specific cell type
A
B
C
D
Cell
Type
Type of
cell
division
somatic
somatic
germline
germline
meiosis
meiosis
mitosis
mitosis
None of the above
6. Cancer cells can divide excessively to
Chromosome
number in
cells
produced
diploid
haploid
haploid
diploid
produce a mass of abnormal cells known as
a tumour.
A tumour cell can double every 40 minutes.
If one tumour cell starts to divide how many
tumour cells will be present after 12 hours?
A 720
3. Which of the following statements about cancer cells is
TRUE?
A.
B.
C.
D.
D
B 32768
C 131072
Cancer cells respond to regulatory signals
Cancer cells cannot spread through the body
Cancer cells cannot divide excessively
Cancer cells can form secondary tumours
D 262144
7. The cell shown below is magnified six
hundred times. What is the actual size of
the cell?
Blood cells and muscle cells are undifferentiated
germline cells
B. Blood cells and muscle cells are differentiated
germline cells
C. Blood cells and muscle cells are undifferentiated
somatic cells
D. Blood cells and muscle cells are differentiated
somatic cells
----------------------
A.
---------------------
4. Which of the following statements is TRUE?
18 mm
A 1080 μm
B 108 μm
C
30 μm
D
3 μm
3
8. The diagram below shows some stages in the development of blood cells
and nerve cells.
(a) What are stem cells?
________________________________________________________
________________________________________________________ (1)
(b) State the location of the tissue stem cells which develop into blood cells.
________________________________________________________(1)
(c) Describe what is meant by the term differentiation.
________________________________________________________
________________________________________________________(1)
4
8. (continued)
(d) Both embryonic stem cells and tissue stem cells are used in medical
research.
Give one reason why embryonic stem cells are potentially more useful
than tissue stem cells.
________________________________________________________
________________________________________________________(1)
(e) (i) Stem cells can be used in research and therapeutics (branch of
medicine relating to the treatment of disease) because stem cells are able
to develop into different types of cells. Explain why stem cells are able to
develop into different types of cells.
________________________________________________________
________________________________________________________(1)
(ii) List 3 therapeutic uses of stem cells.
1. __________________________________________________
2. __________________________________________________
3. __________________________________________________(3)
(f) Tumours can be found in patients suffering from cancer.
(i) Describe what a tumour is:
__________________________________________________
__________________________________________________(1)
(ii) Describe how a secondary tumour develops:
__________________________________________________
__________________________________________________(1)
5
Sub topic 2: DNA and it’s replication
1. A DNA molecule consists of 4000 nucleotides of which
20% contain the base adenine.
How many of the nucleotides in this DNA molecule will
contain guanine?
A
800
B
1000
C
1200
D
1600
2. A fragment of DNA was found to have 120 guanine
bases and 60 adenine bases. What is the total number
of sugar molecules in this fragment?
A: 60
B: 90
C: 180
D: 360
3. If ten percent of the bases in a molecule of DNA are
adenine, what is the ratio of adenine to guanine in the
same molecule?
A: 1:1
B: 1:2
C: 1:3
D: 1:4
4. A DNA nucleotide could be formed from a molecule of
phosphate together with
A.
Ribose sugar and guanine
B. Ribose sugar and uracil
C.
Deoxyribose sugar and guanine
D. Deoxyribose sugar and uracil
6
E.
5. DNA controls the activities of a cell by coding for the
production of
6.
A
proteins
B
carbohydrates
C
amino acids
D
bases
If a DNA molecule contains 8000 nucleotides of which
20% are adenine, then the number of guanine
nucleotides present is:
A
B
C
D
1600
2000
2400
3200
7. The table below refers to the mass of DNA in
certain human body cells.
Cell type
liver
Lung
P
Q
Mass of DNA in cell (x10-12g)
6.6
6.6
3.3
0.0
Which of the following is most likely to identify correctly cell
types P and Q?
P
Q
A
Kidney cell
Sperm cell
B
Sperm cell
Mature red
blood cell
C
Mature red blood cell
Sperm cell
D
Nerve cell
Mature red
blood cell
7
8.How many adenine molecules are present in a DNA
molecule of 4000 bases, if 20% of the base molecules are
cytosine?
A
400
B
600
C
800
D
1200
9. Which of the following statements about DNA replication
is correct?
A
Polymerase adds nucleotides to the 3’
end of a DNA strand
B
Polymerase adds nucleotides to the 5’
end of a DNA strand
C
Ligase adds nucleotides to the 3’ end of
a DNA strand
D
Ligase adds nucleotides to the 5’ end of
a DNA Strand
10.Thirty percent of bases in a DNA molecule are adenine.
The percentage of cystosine bases in the same molecule is
A
20%
B
30%
C
40%
D
70%
8
11. Which of the following diagrams correctly represents part of a DNA molecule?
The letters A, T, U, C and G represent bases.
A.
3’
5’
B. 3’
C. 5’
D.
3’
A
C
T
A
T
T
A
C
U
A
C
G
3’
5’
5’
12. The two components which make up the backbone of each DNA strand are
A
B
C
D
Ribose and phosphate group
Deoxyribose and phosphate group
Deoxyribose and base pairs
Phosphate group and thymine
13. Which of the following statements about the structure of DNA is TRUE?
A.
B.
C.
D.
In DNA the base pairs are held together by peptide bonds.
Fragments of DNA are joined together by ligase
Fragments of DNA are joined together by polymerase
DNA contains the bases represented by the letters A, U, C and G.
9
14.The diagram below shows part of a DNA molecule.
T
A
X
T
Y
1
(a) (i) Copy the diagram and then, on your diagram, draw a circle around one
nucleotide.
(ii) Name parts X and Y
X _______________________________________________
Y _______________________________________________
1
(b) Name the two DNA bases not shown in the diagram.
______________________________ and _____________________________ 1
(c) A DNA molecule was found to contain 15000 nucleotides.
What is the maximum number of amino acids which could be coded for by this
molecule?
_____________________
1
10
Sub topic 3: RNA, transcription, translation
1. The function of tRNA in cell metabolism is to
A
B
C
D
transport amino acids to be used in synthesis of proteins
carry codons to the ribosomes
synthesise proteins
transcribe the DNA code
2. The following information refers to protein synthesis.
tRNA anticodon
amino acid carried by
tRNA
Histidine (his)
Alanine (ala)
Arginine (arg)
Tyrosine (tyr)
Methionine (met)
Threonine (thr)
GUG
CGU
GCA
AUG
UAC
UGU
What order of amino acids would be synthesised from the base sequence of DNA shown?
Base sequence of DNA
C G T T A C G T G
A
arg
-
tyr
-
his
B
ala
-
met
-
his
C
ala
-
tyr
-
his
D
arg
-
tyr
-
thr
3. The table below contains statements which may be TRUE or FALSE with regard to DNA
replication and mRNA synthesis.
Which line in the table is correct?
Statement
A
Occurs in the
nucleus
B
Involved in
protein
synthesis
Requires free
nucleotides
Involves
specific base
pairing
C
D
DNA
Replication
TRUE
mRNA
synthesis
FALSE
TRUE
TRUE
TRUE
FALSE
TRUE
TRUE
11
4. The diagram represents part of a molecule of DNA on which a molecule of RNA is being
synthesised.
What does component X represent?
A
Ribose sugar
B
Deoxyribose sugar
C
Phosphate
D
Ribose phosphate
5. The diagram shows a stage in the synthesis of part of a polypeptide.
Tyrosine
Amino acid
tRNA
mRNA
T
A
T
DNA
Identify the triplet codes for the amino acid tyrosine.
mRNA
tRNA
A
ATA
UAU
B
UAU
AUA
C
AUA
UAU
D
ATA
TAT
12
6.The diagram below illustrates the two main stages of protein synthesis.
(a) Describe three differences between DNA and mRNA.
1. ______________________________________________________________
______________________________________________________________
______________________________________________________________
2. ______________________________________________________________
______________________________________________________________
______________________________________________________________
3. ______________________________________________________________
______________________________________________________________
2
13
6(continued)
(b) Name bases 3, 8 and 11.
________, _________, ____________
2
(c) Where in the cytoplasm does stage 2 take place
________________________________________________
1
(d) Name molecules X and Y.
X _______________________
7(a)
Y_______________________ 1
The diagram shows part of an mRNA molecule being formed on a strand of
DNA.
A
C
A
T
G
A
C
A
C
G
A
G
m RNA
(i)
In which part of the cell is mRNA formed?
___________________________________
1
(ii)
Copy the diagram above and then, on your diagram, complete the
mRNA molecule by filling in the correct base sequence.
(iii)
How many amino acids are coded for by this section of mRNA?
__________________________________________________
14
1
8.(a)
The diagram below shows a section of a messenger RNA (mRNA) molecule.
Phosphate=
Sugar =
guanine
(i)
uracil
adenine
Name the sugar that is present in mRNA
_________________________________
(ii)
1
Which base found in mRNA is not shown in the diagram?
_________________________________
(iii)
Name two parts of a cell where mRNA is found.
1. ____________________________________
2. ____________________________________
(b)
1
DNA templates are used to produce mRNA molecules.
(i)
Copy the table below and insert the names of the DNA bases which
pair with the RNA bases shown.
DNA base
RNA base
adenine
uracil
guanine
1
(ii)
Apart from free RNA nucleotides and a DNA template, name one
other molecule that is essential for mRNA synthesis.
_____________________________________________
1
(iii)
Describe the part played by a mRNA molecule in the manufacture of a
cell protein.
____________________________________________________
____________________________________________________
15
3
9.The formation of a mRNA strand on a section of a chromosome is shown in the
diagram below.
(a) Give the names of bases 1, 2 and 3.
1. ______________ 2. ____________________ 3.__________________ 1
(b) The mRNA strand is constructed from free nucleotides.
Name the two molecules which combine with a base to form a mRNA nucleotide.
1. _____________________ 2.______________________
1
(c) Once completed, the mRNA strand moves into the cytoplasm.
What is its destination?
______________________________________________________________ 1
(d) Explain why the formation of mRNA strands is essential to cell metabolism.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________ 2
16
10.
The diagram shows the synthesis of a peptide chain.
(a) Name bond X and molecule Y.
Bond X __________________________
Molecule Y __________________
2
(b) What term is used to describe the triplet code on the tRNA molecules?
__________________________________________
1
(c) Give the abbreviated names of the next four amino acids which will be attached
to complete the peptide chain.
Iso
_________  _________ ________ _______ ___________
1
(d) What sequence of bases on a DNA molecule will code for the amino acid labelled
thr?
______________________________________________
1
(e) Amino acids are added to the peptide chain at the rate of 15 per second.
How long will it take for the complete synthesis of the peptide shown in the
diagram above?
_____________s
1
17
11. The diagram below shows a section through a nucleus and associated cell structures.
(a) (i)
Name organelle X.
_________________________________
1
(ii) What type of substance is manufactured by organelle X?
______________________________
1
(iii) Give an example of such a substance.
______________________________
1
12. The diagram below shows one gene within a chromosome.
non coding region of the gene
(a)
coding region of the gene
State what non-coding regions of a gene are called.
__________________________________________
(b)
1
Explain why it is important that non-coding regions are removed from the
primary transcript of this gene before translation.
________________________________________________________
________________________________________________________
18
1
(c)
The diagram below shows part of one coding region of the mRNA from this
gene.
U
G U C G G A
C A U G U C A C
U
U G
How many different types of amino acid are coded for by this region of the
mRNA strand?
____________________________________
19
1
Sub topic 4: Proteins, mutations and genetic disorders
1. Which type of gene mutation occurs when a codon for an amino acid is
replaced by a stop codon?
A Nonsense
B Missense
C Frameshift
D Splice-site
2. Individuals with Cri-du-chat syndrome have a shortened chromosome 5.
No other chromosomes are affected
Which type of mutation causes Cri-du-chat syndrome?
A Deletion
B Insertion
C Duplication
D Translocation
3. In Duchenne Muscular Dystrophy (DMD) one amino acid codon is substituted
with a stop codon. What type of gene mutation is this?
A.
B.
C.
D.
Missense
nonsense
frameshift
splice-site
4. In cystic fibrosis (CF) one base pair is deleted. This is an example of
A: Missense
B: nonsense
C: frameshift
D: splice-site
20
5. Copy and complete the table below about gene mutations:
Type of mutation
Missense
Description
Substituted nucleotide results in a stop codon, so
the polypeptide is shorter.
This is the result of a deletion or insertion
mutation and the entire sequence of triplets after
this point will be wrong.
(3)
6.Whole sections of chromosomes can be altered by mutation, affecting several
genes. Give an account of the three types of chromosome mutations.
21
(3)
Sub topic 5: Human Genomics
1. During the polymerase chain reaction (PCR) samples of DNA are repeatedly heated and
cooled.
Why are the samples cooled?
A
To denature DNA polymerase
B
To slow the reaction down
C
To allow primers to bind to target sequences
D
To separate the DNA strands
2. What is the function of a DNA probe?
A
To replicate a particular region of DNA
B
To join fragments of DNA together
C
To remove non-coding sections of DNA
D
To detect the presence of specific DNA
sequences
22
3. The diagram below shows the results of a paternity
test. It compares DNA samples from five individuals.
Woman S is the mother of child X and child Y. Men P
and Q are possible fathers of these children.
Woman
S
Man
P
Man
Q
Child
X
Child
Y
Which of the following conclusions can be drawn from
these results?
A
B
C
D
Man P could be the father of child X
Man P could be the father of child Y
Man Q could be the father of child X
Man Q could be the father of child Y
4. Which of the following lines regarding DNA amplification is TRUE?
A.
B.
Melting
Heating the DNA to
separate the
strands
Complementary
strands of target
23
Annealing
Primers bind at two
ends of the region
to be amplified
Heating the DNA to
separate the
Extending
Complementary
strands of target
DNA are made
Primers bind at two
ends of the region
DNA are made
Primers bind at two
ends of the region
to be amplified
Heating the DNA to
separate the
strands
C.
D.
strands
Heating the DNA to
separate the
strands
Complementary
strands of target
DNA are made
to be amplified
Complementary
strands of target
DNA are made
Primers bind at two
ends of the region
to be amplified
5. How many cycles of PCR have been completed if 128 molecules of DNA were
produced from one double DNA helix?
A. 5
B. 6
C. 7
D. 8
24
25
Sub topic 6 Metabolism and Enzymes
1. The diagram below shows a metabolic pathway that is controlled by end product inhibition.
Substance 1
Enzyme 1
Substance 2
Enzyme 2
Substance 3
Enzyme 3
Substance 4
For Substance 4 to bring about end product inhibition, with which of the following would it
interact.
A. Enzyme 1
B. Enzyme 3
C. Substance 1
D
Substance 3
2. The graph shows the effect of substrate concentration on the rate of an enzyme-catalysed
reaction.
At what substrate concentration is the reaction rate equal
to 75% of the maximum rate?
A. 6 units
B. 8 units
C. 12 units
D. 18 units
26
3. The graph shows the effect of substrate concentration on the rate of an enzyme-controlled
reaction.
X
Y
Rate
of
reaction
Substrate concentration
The graph levels out between points X and Y because the
A. enzyme is denatured
B. active sites are saturated with substrate
C. enzyme is inhibited
D
enzyme is activated
4. The following table gives information on the control of metabolic pathways using inhibitors.
Which line in the table is CORRECT?
Type of inhibitor
A.
B.
C.
D.
Competitive
Binds to active site of
the enzyme
Non-competitive
Changes shape of
active site of enzyme
End product binds to
an enzyme that
catalyses a reaction
early in the pathway
Changes shape of
active site of enzyme
Changes shape of
active site of enzyme
Binds to active site of
the enzyme
End product binds to
an enzyme that
catalyses a reaction
early in the pathway
27
Binds to active site of
the enzyme
Feedback inhibition
End product binds to
an enzyme that
catalyses a reaction
early in the pathway
Binds to active site of
the enzyme
End product binds to
an enzyme that
catalyses a reaction
early in the pathway
Changes shape of
active site of enzyme
5. The diagram below represents a reaction catalysed by an enzyme in the
cytochrome system.
(a) What name is given to the part of the enzyme where this reaction occurs?
____________________________________________________________
1
(b) Name the product of this reaction.
____________________________________________________________
1
(c)Cyanide is a poison which inhibits this enzyme.
Suggest how cyanide is able to do this.
____________________________________________________________
____________________________________________________________
28
1
6.The graph shows the effect of increasing substrate concentration on the rate of
this reaction.
Rate of
reaction
Substrate concentration
(i)
Explain why the graph levels out at high substrate concentration.
__________________________________________________________
__________________________________________________________
(ii)
1
Assuming that the enzyme is operating at its optimum pH and temperature,
suggest how the rate of reaction could be increased at high substrate
concentrations.
___________________________________________________________
___________________________________________________________
29
1
Sub topic 7: Respiration
1. During which of the following chemical conversions is
ATP produced?
A
Amino acids  protein
B
Glucose  pyruvic acid
C
Haemoglobin oxyhaemoglobin
D
Nucleotides mRNA
5.The diagram below shows energy transfer
within a cell.
energy
Compound Y
Which line in the table below identified
correctly compounds X and Y?
Glycolysis takes place in the mitochondrion.
The mitochondrion has two membranes.
The rate of respiration is affected by temperature.
A
B
C
D
Which of the above statements are correct?
A.
B.
C.
D.
energy
Cellular
Processes
s
2. The following statements relate to respiration and the
mitochondrion.
1
2
3
Compound X
+
phosphate
1 and 2
1 and 3
2 and 3
All of them
X
glucose
glucose
ADP
ATP
Y
ATP
ADP
ATP
glucose
6.The following chart shows stages in the
complete breakdown of glucose in aerobic
respiration.
3.In the absence of oxygen the breakdown of glucose
splits from the aerobic pathway of respiration…
Glucose
A after the formation of pyruvate
Stage X
B after the formation of acetyl CoA
Pyruvate
C after the formation of citric acid
Stage Y
D at the start of glycolysis.
Citric acid cycle
Stage Z
4.In respiration, the products of the electron transfer
system are
At which stage or stages is hydrogen released to be
picked up by hydrogen acceptors?
A hydrogen and carbon dioxide
B water and ATP
C oxygen and ADP
D pyruvate and water.
A.
B.
C.
D.
30
Stages X, Y and Z
Stages X and Y only
Stages Y and Z only
Stage Z only
7.In respiration, the sequence of reactions resulting in the
conversion of glucose to pyruvare is called
A. the cytochrome system
11. The graph below shows changes which
occur in the masses of protein, fat and
carbohydrate in a person’s body during seven
weeks without food.
B. the TCA cycle
C. the Krebs cycle
D. glycolysis.
8. The diagram shows part of a liver cell with four parts
labelled. In which part is most ATP produced?
Weeks without food
The person’s starting weight was 60kg.
Predict their weight after two weeks without
food.
9. Glycolysis takes place in the
F.
nucleus
A. 57kg
B. 54kg
C. 50kg
D. 43kg
G. Inner membrane of mitochondria
H. matrix of mitochondria
I.
12.The diagram below represents stages in tissue
respiration.
cytoplasm.
10. The following diagram represents stages in the
complete breakdown of glucose in aerobic respiration.
oxygen
ADP+P
D
+
Glucose
Stage X
A
Pyruvate
Stage Y
Krebs cycle
Stage Z
B
+
At which stage, or stages, is carbon dioxide released?
A. Stages X and Z
B. Stages X and Y
C. Stages Y and Z
D. Stage Z only.
31
C
carbon
dioxide
Which box represents ATP?
relaxed
muscle
13. Which of the following statements about the role of dehydrogenase enzyme in respiration is
TRUE?
A. Dehydrogenase enzymes remove oxygen ions from a substrate
B. Dehydrogenase enzymes add hydrogen ions to a substrate
C. Dehydrogenase enzymes remove hydrogen ions from a substrate
D. Dehydrogenase enzymes add oxygen ions to a substrate
14. The diagram below shows two stages of respiration
Glucose
Stage A
Pyruvate
Acetyl coenzyme A
(a) (i) Identify stages A and B.
Stage A ________________________________________________
Stage B ________________________________________________
(ii) Name Substance X.
________________________________________________________
(b) During Stage A, glucose is converted to pyruvate.
Name the molecule that provides phosphate for this conversion.
_________________________________________________________
(c) The conversion of citrate to substance X in Stage B involves several reactions.
32
1
Name two molecules, apart from NADH, which are produced during these reactions.
1. ____________________________________________________________
2. ____________________________________________________________
1
(d) Phosphofructokinase is an enzyme involved in Stage A.
The presence of excess citrate inhibits this enzyme.
Explain why this is important in the conservation of resources in the cell.
_________________________________________________________________
_________________________________________________________________
33
1
15. The diagram below shows some of the reactions which occur during aerobic respiration.
glucose
Stage A
Pyruvic acid
acetyl CoA
4-carbon
compound
Stage B
reduced
molecule R
Citric acid
Molecule R
water
Stage C
molecule S
(a) Complete the table by naming stages A, B and C and indicating their exact location within
cell.
Stage
A
Name
Location
B
C
3
(b) Complete the following sentences by naming molecules R and S and describing their
function with respect to stage C.
34
R is ________________________________and its function is __________________
S is _______________________________and its function is ___________________
16 .The diagram below represents two stages in the chemistry of respiration in a cell
which is respiring aerobically.
Glucose
3-carbon compound
Coenzyme A (CoA)
X
Acetyl (2C) coenzyme A
4 – carbon
compound
6 – carbon
compound
5 – carbon
compound
(a) Name the 3-carbon compound and the 6-carbon compound.
3C _______________________________________________________
6C _______________________________________________________
(b) Copy the diagram and draw a line across it to indicate where this series of reactions
would stop if oxygen were not available.
2
1
(c) State the precise location of the Krebs cycle within the cell
____________________________________________________________
(d) Complete the table below to name product X and to describe what happens
to each of the products.
Product
Fate of product
35
1
X _________________
Hydrogen
17. Which of the following equations describes correctly the role of creatine phosphate?
A ADP + phosphate + creatine
creatine phosphate + ATP
B creatine phosphate + ADP
ATP + creatine
C creatine phosphate + ATP
ADP + phosphate + creatine
D ATP + phosphate
creatine phosphate + ADP
18.The diagram below shows three stages that occur during aerobic respiration.
Stage X
Reactions in the
cytoplasm
1
Stage Y
Reactions in
matrix of
mitochondrion
2
Stage Z
Reaction in
Inner
menbrane of
mitochondrion
metabolic products
(a).Name each stage.
X _______________________________________________________
Y _______________________________________________________
Z _______________________________________________________
(b) Arrows 1 and 2 represent the transfer of molecules from one stage to another.
Copy and complete the table to identify these molecules.
Arrow
Name of molecule
1
2
2
(c) Name the two metabolic products of stage Z.
____________________________ and ________________________
(d)The diagram below shows a mitochondrion from a skin cell.
36
1
Describe how the structure of mitochondrion from an active muscle cell would differ
from the one shown. Give a reason for your answer.
Structural difference __________________________________________________
__________________________________________________________________
1
Reason ___________________________________________________________
__________________________________________________________________
1
19.The diagram below shows the metabolism of three energy sources in a cell.
proteins
carbohydrates
Intermediate compound
X
fats
glycerol
pyruvate
Gas Z
acetyl CoA
(a)
Y
Name X, Y and Z
X ________________________________
Y ________________________________
Z ________________________________
(b)
2
What term describes the breakdown of carbohydrate into pyruvate during
respiration?
______________________________________________________________
(c)
1
Describe what happens to acetyl CoA after it enters the citric acid cycle.
______________________________________________________________
______________________________________________________________
37
1
20.The diagram shows the role of ATP in cell metabolism.
+
glucose + oxygen
proteins
Pathway X
process Y
+
ATP
(a)Copy and complete the diagram by entering the names of the appropriate substances.
3
(b)Name one stage of pathway X and state where it occurs in the cell.
Stage _________________________ Location _______________________
1
(c) Name the organelle where process Y occurs.
___________________________________________________________
1
(d)Name a respiratory substrate other than glucose.
_____________________________________________________________
1
21(a) The table below contains three statements about two stages of cellular respiration.
Copy and complete the table to indicate whether the statements are True (T) or False (F) for
each stage.
Stages of Respiration
Statement
Glycolysis
Cytochrome System
Occurs in the
mitochondrion
T
Releases carbon dioxide
F
Uses oxygen
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(b)The diagram below summarises anaerobic respiration in a muscle cell.
Glucose
(6C)
X
(3C)
Lactic acid
(3C)
Pathway Y
(i)
Name substance X
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(ii)
Which substance would need to be present for pathway Y to occur?
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(iii)
1
Why is anaerobic respiration considered to be a less efficient process
than aerobic respiration?
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(iv)
1
1
Glucose is not stored in muscle cells.
Name the carbohydrate which is stored in muscle cells.
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