Download Biochem REVIEW Answer KEY

Biology 12
NAME__________________
Biochemistry Review
Outlines: Experimental Design, Dehydration Synthesis and Hydrolysis, Water, Lipids,
Carbohydrates, Proteins, Nucleic Acids, DNA Replication, Protein Synthesis, Recombinant
DNA technology, ATP. – that’s 11 total!!
1. Experimental Design: Enzymes are proteins that catalyze (speed up)
reactions in organisms. Since the average temperature of the human body
is 37℃, the enzymes in humans normally function at that temperature.
A scientist wonders if temperature affects the rate of an enzyme
catalyzed reaction. Design an experiment to answer the scientist’s
question.
Hypothesis: Temperature affects the ability of an enzyme catalyzed
reaction
Testable prediction: If temperature affects the ability of an enzyme
catalyzed reaction then varying the temperature will vary the reaction rate.
Experimental Variable: Temperature
Dependent Variable: Reaction Rate
Control Group: Test Tubes at 37℃ with enzyme (min 10 samples)
Experimental Groups: Group 1- Test tubes at 20 ℃ with enzyme
Group 2- Test tubes at 30 ℃ with enzyme
Group 3- Test tubes at 50 ℃ with enzyme
(min 10 samples per group)
Constant Factors: Enzyme type, source of enzyme, amount of enzyme,
environment- pH, time of reaction, size of test tube, amount of solute and
substrate.
2. Explain why the intermolecular bonds are present in water, where are they
present in water?
Due to the attraction between opposite
charges, the partially positive hydrogen
end will be attracted to the partially
negative oxygen end.
3. What is the biological significance of water’s intermolecular bonds to
organisms?
Effective polar solvent
High Heat Capacity
High Heat of Vaporization
High Surface tension
Ice is less dense than Liquid
***know the details of each***
4. The pH scale is a measure of [H+] :
pH
[H+]
[OH-]
2
1 x 10-2
1 x 10-12
[H+]vs[OH-]
[H+]>[OH-]
Acid/base
acid
7
1 x 10-7
1 x 10-7
[H+]=[OH-]
neutral
10
1 x 10-10
1 x 10-4
[H+]<[OH-]
base
5. Carbohydrates:
Glucose
Mono/di/
Description
Function
polysaccharide
mono
Hexose – 6 carbon sugar Short term
energy storage
Ribose
mono
Pentose- 5 carbon sugar Makes up part
of RNA
Deoxyribose
mono
Pentose- 5 carbon sugar
Makes up part
of DNA
Sucrose
di
Glucose + fructose
Maltose
di
2 glucose
Lactose
di
Glucose + galactose
Carbohydrate
transport in
plants
Energy storage
in plants and
animals
Energy storage
in mammals
Starch
poly
Glucose polymer with
some branches
α 1-4 linkages
Glucose storage
in plants
Glycogen
poly
Glucose polymer with
many branches
α 1-4 linkages
Glucose storage
in animals
Cellulose
poly
Glucose polymer with no Component of
branches, linear
Cell WALL in
plants
β 1-4 linkages
6. Lipids: What are the 3 major classes of lipids and what is the unifying
characteristic of most lipids?
Neutral fats (triglycerides), Phospholipids, Steroids
Nonpolar, hydrophobic and thus insoluble in water
7. Draw each class of lipid and state the function
8. Neutral fats (triglycerides),
long term energy storage
prevent heat loss in animals
Phospholipids,
form the phospholipid bilayer which serves as the
framework for the cell membrane
Steroids
Cholesterol- makes other steroids and stabilize the cell membrane
Estrogen and Progesterone- female sex hormones
Testerone- male sex hormones
Aldosterone- control blood sodium levels and blood pressure
Cortisol- reduces inflammation
9. Illustrate and describe in words the formation of a dipeptide.
Dehydration Synthesis-a peptide bond is formed by removing a water, the
hydroxyl group from the carboxyl end of one aa and a hydrogen atom from
the amino end of the other aa.
10.Draw and label all parts of an amino acid and describe what happens to
each group in slightly acidic conditions.
11. Explain seven functions of proteins
a)
Enzymes act as catalysts by speeding up chemical reactions.
b) Transport proteins carry molecules in organisms
c) Structural proteins are components of various structures
d) Some Hormones are proteins since they travel in the blood to target
tissues or organs where they stimulate certain responses
e) Receptor proteins on cell membranes allow chemical signals to binds to
the cell.
f) Contractile proteins allow movement
g) Some proteins provide protection against disease (antibodies)
12.
Levels of Protein Structure:
Level of structure
Definition
Linear sequence of
Primary 1◦
amino acids in the
polypeptide
Orientation or pattern
Secondary 2◦
which the polypeptide
assumes, αhelix or
βpleated sheet
Folding upon itself,
forming a globular
Tertiary 3◦
structure
Quarternary 4◦
Combination or two or
more polypeptides to
form the final protein
Stabilizing bonds
peptide
hydrogen
Hydrogen, ionic,
covalent, hydrophobic
interactions
Hydrogen, ionic and
covalent
12. Draw a labeled DNA nucleotide, single strand of DNA and double helix.
a. DNA nucleotide
b. Single strand of DNA
c. Double helix
13.
Draw a flow diagram included all the steps and enzymes involved
in DNA replication
 The enzyme DNA helicase unwinds and unzips the DNA by breaking
hydrogen bonds.
 Creates a replication fork which both parental strands serve as templates
 Enzyme DNA polymerase builds daughter strands using free floating DNA
nucleotides and the template.
 DNA ligase and polymerase join the daughter strand nucleotides by
creating phosphodiester bonds
 Each new strand and its complementary parent strand, linked by hydrogen
bonds, coil to form two new double helixes
14.
Explain what is meant by semi-conservative replication
Each new helix consists of one new strand and one old strand.
15.
What is the purpose of DNA replication and what is the purpose of
protein synthesis?
DNA replication occurs before mitosis, to provide daughter cells with the same
DNA that the parental cell had, allowing them to produce all the same proteins
that the parental cell could.
Protein synthesis occurs to produce proteins using the genetic information
contained in the DNA
16.
What are the 3 complementary base pairing rules?
a) Adenine always pairs with thymine. Forms 2 hydrogen bonds
b) Guanine always pairs with cytosine. Forms 3 hydrogen bonds
c) A two ring purine always pairs with a one ring pyrimidine
17.
Describe all the steps in the following diagram: starting with DNA
ending with the polypeptide chain.
Transcription – RNA polymerase binds to the promoter
-RNA polymerase unwinds and unzips the DNA
-Only ONE strand used as the template
-RNA polymerase links RNA nucelotides together based on
the template stand
-Elongation continues until a termination site is reached on
the DNA
-The mRNA is released, travels from nucleus to cytoplasm
-DNA resumes its double helix configuration
Translation
-mRNA combines with the ribosome, sandwiched between the large and small
subunits
-The first two mRNA codons will be in the ribosome
-Two tRNA’s with complementary anticodons to the mRNA codons enter the
ribosome
-Each tRNA carries a specific amino acid
-A peptide bond forms between the aa and the ribosome shifts along the
mRNA, releasing the first tRNA.
-The third mRNA codon is now in the ribosome, and a third tRNA enters,
bringing its aa.
-A peptide bond will form between the second and third aa.
-The polypeptide will continue to be elongated until a termination codon is
reached
18.Compare and contrast the structure of DNA and RNA
Similarities
Pentose sugars
Phosphate groups
Sugar-phosphate backbone
Phosphodiester bonds
Nitrogenous bases- A,G,C
Composed of nucleotides
Differences
DNA- double helix
RNA- linear or globular
DNA- double stranded
RNA- single strand
DNA- deoxyribose
RNA- ribose
DNA- thymine
RNA- uracil
19. What are 3 uses of rDNA?
Producing multiple copies of a gene:
a) Gene sequencing
b) Inserted into organisms to alter genotype and phenotype
i. Bacteria- degrade oil, degrade PCB, fix nitrogen
ii. Plants- resist diseases and insects, resist water shortage,
survive in salty soils
iii. Animals- grow faster, produce human proteins
c) Producing Proteins for a particular gene
i. Insulin
ii. Growth hormone
iii. Interferon
iv. Factor 8
20.
Explain in detail the steps involved in producing insulin through
Recombinant DNA technology.
a) Plasmid removed from bacteria and cleaved using specific restriction
endonucleases- creating sticky ends
b) Human gene is cleaved using the same type of restriction endonucleases
in order to create complementary sticky ends
c) Human gene and bacterial plasmid are spliced using DNA ligase creating
recombinant DNA plasmid
d) Recombinant DNA plasmid is added back to the bacterial cell
e) Cultured- producing millions of genetically identical daughter cells.
f) Since each daughter cell has a copy of the human gene it will be able to
produce the human protein
g) The protein can then be collected and used for various purposes such as
treating disease.
21.
How is ATP described as a nucleotide?
Consists of 3 phosphates, a nitrogenous base- adenine and a pentose sugarribose.
22.
Draw and explain the ATP cycle. Where does the energy go and how
is it replaced?
Energy can be used for
pathways such as protein
synthesis which require
energy
Energy can be supplied by
aerobic cellular respiration
(ACR)