exam

Question 1

Which one of the following statements correctly describes “telomerase”?

Select one:

a. It creates repetitive DNA at the end of the chromosomes.
b. Telomerase uses the DNA as a template for synthesizing a new strand.
c. Activity of this enzyme is inhibited in many cancerous cells.
d. This enzyme is active in all dividing cells.

Answer 1

a. It creates repetitive DNA at the end of the chromosomes.

Question 2

A young cat has never had much energy. He is brought to a veterinarian for help and is sent to the animal hospital for some tests. There they discover his cells produce much more lactate than normal cats. Of the following, which is the best explanation for his condition?

Select one:

a. His cells lack the transport protein that moves glucose across the mitochondrial membrane.
b. His cells cannot move NAD+ from glycolysis to the mitochondrial electron transport chain.
c. His cells have a low O2 concentration so he is using fermentation for energy.
d. ATP Synthase is overactive.

Answer 2

c. His cells have a low O2 concentration so he is using fermentation for energy.

Question 3

Determine the type of reaction and ∆G demonstrated in the diagram below. Would you expect the products to store more or less energy than the reactants in this situation?

a. Exergonic; ∆G is negative; more energy stored in products. I
b. Endergonic; ∆G is positive; more energy stored in products.
c. Endergonic; ∆G is negative; less energy stored in products.
d. Exergonic; ∆G is positive; more energy store in products.
e. Exergonic; ∆G is negative; less energy stored in products.

Answer 3

e. Exergonic; ∆G is negative; less energy stored in products.

Question 4

Which one of the following statements about nucleosomes is INCORRECT?

Select one:

a. The nucleosome core contains an octet of 8 histone proteins.
b. The nucleosome core is wrapped by the DNA double helix.
c. There are two copies of each histone protein in the nucleosome core.
d. Four copies of histone H1 are present in the nucleosome core.

Answer 4

d. Four copies of histone H1 are present in the nucleosome core.

Question 5

Where is the electron transport chain associated with photosystem II found?

Select one:

a. Plasma membrane.
b. Thylakoid lumen.
c. Stroma of the chloroplast.
d. Thylakoid membrane.

Answer 5

d. Thylakoid membrane.

Question 6

A thylakoid membrane is punctured/ripped (has a hole in it)! This damage will have the most direct effect on which of the following processes?

Select one:

a. The absorption of light energy by photosystem 1.
b. ATP synthesis by chemiosmosis.
c. The carbon fixation stage of the Calvin cycle.
d. The splitting of water for electrons.

Answer 6

b. ATP synthesis by chemiosmosis.

Question 7

When would a cell utilize the process of exocytosis?

Select one:

a. When secreting protein and wastes from the cell.
b. When pumping protons down a concentration gradient.
c. When ingesting nutrients.
d. When replicating.

Answer 7

a. When secreting protein and wastes from the cell.

Question 8

A membrane protein permits the movement of an ion into the cell along its concentration gradient. The energy from this movement is used to transport glucose out of the cell. This is an example of:

Select one:

a. primary active transport.
b. osmosis.
c. simple diffusion.
d. antiport.

Answer 8

d. antiport.

Question 9

Why are fermentation reactions important for cell?

Select one:

a. They utilize oxygen.
b. They generate oxygen.
c. They regenerate NAD+ so that glycolysis can continue.
d. They produce alcohol used in alcoholic beverages.

Answer 9

c. They regenerate NAD+ so that glycolysis can continue.

Question 10

White blood cells engulf bacteria through what process?

Select one:

a. Pinocytosis
b. Receptor-mediated exocytosis
c. Osmosis
d. Exocytosis
e. Phagocytosis

Answer 10

e. Phagocytosis

Question 11

A metabolic pathway has the following series of coupled reactions. A→B→C
Reaction #A has a ΔG = -30kcal/mol
Reaction #B has a ΔG = +50kcal/mol
Reaction #C has a ΔG = -6kcal/mol
Identify each reaction as either endergonic or exergonic AND determine whether enough free energy is present for the coupled reactions to occur spontaneously.
Select one:
a. Exergonic, endergonic, exergonic, not spontaneous.
b. Endergonic, exergonic, endergonic, spontaneous.

Answer 11

a. Exergonic, endergonic, exergonic, not spontaneous.

Question 12

A mutation to DNA polymerase that eliminated the 3¢-to-5¢ exonuclease activity would prevent:
Select one:
a. removal of base mismatches. 
b. ligation of the okazaki fragments.
c. removal of the RNA primer.
d. repair of deaminated bases.

Answer 12

a. removal of base mismatches.

Question 13

Rotenone is a poison commonly added to insecticides. This molecule binds to the first electron carrier in the electron transport chain. Which of the following best describes the effect of rotenone on an insect?

Select one:

a. The insect will die because high levels of ethanol will be produced.
b. The insect will die because anaerobic respiration in unable to occur.
c. The insect will die because insufficient ATP was produced.
d. The insect will die because glucose can no longer be split to create pyruvic acid.

Answer 13

c. The insect will die because insufficient ATP was produced.

Question 14

A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the external solution relative to the cytoplasm of the cell?

Select one:

a. Hypertonic
b. Isotonic
c. Hypotonic

Answer 14

b. Isotonic

Question 15

A chemical reaction with a negative ∆G fails to move forward (start). Why may this occur?

Select one:

a. The system is endergonic and requires the addition of ATP.
b. The activation energy has not been met.
c. A high concentration of the required enzyme is present.
d. The system is stable and thus not spontaneous.

Answer 15

b. The activation energy has not been met.

Question 16

The conversion of NADH → NAD+ is known as \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_. The conversion of FADH2 FAD is known as \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_.
Select one:
a. Reduction, reduction
b. Oxidation, reduction
c. Reduction, oxidation
d. Oxidation, oxidation

Answer 16

d. Oxidation, oxidation

Question 17

The genome of a typical bacterium contains about 5 x 106 base pairs and can be replicated in about 30 minutes. The human genome is 600X larger (3 x 109 base pairs) and at the rate of a bacterium would require 300 hours (~12 days) to be replicated; yet the entire human genome can be replicated with several hours. How is this possible?

Select one:

a. Human DNA contains more origins of replication than prokaryotic DNA.
b. Human DNA polymerases work much faster than those of prokaryotes.
c. Eukaryotic DNA is simpler to replicate than prokaryotic DNA.
d. The nucleosomes of eukaryotic DNA allow for faster DNA replication.

Answer 17

a. Human DNA contains more origins of replication than prokaryotic DNA.

Question 18

How does CO2 created during cellular respiration exit an animal cell?

Select one:

a. Antiport transporter.
b. Facilitated diffusion.
c. Carrier protein.
d. Simple (passive) diffusion.

Answer 18

a. Antiport transporter.

Question 19

which of the following statements about energy and thermodynamics is correct?

a. earth is an isolated system
b. living organisms are closed systems
c. energy conversions can never be 100% efficient
d. the total amount of energy in the universe is always decreasing

Answer 19

b. living organisms are closed systems

Question 20

for a reaction to be exergonic, which of the following must occur?

a. it must also be exothermic
b. there must be an input of energy to proceed
c. products must have less enthalpy than reactants
d. products must have less free energy that than reactants
e. the entropy of the products

Answer 20

d. products must have less free energy that than reactants

Question 21

the inside of the cell has a high solute concentration relative to the surrounding solution. what’s the tonicity of the surrounding solution?

Answer 21

hypertonic

Question 22

suppose 10 glucose molecules undergo glycolysis simultaneously. what’s the net total of ATP produced per glycolysis pathway?

a. 20
b. 40
c. 4

Answer 22

b. 40

Question 23

which of the following is true regarding the KC

1. CO2 is released
2. ATP is produced by substrate level phosphorylation
3. NADH and FADH2 will shuttle
4. all of the above are correct

Answer 23

4. all of the above are correct

Question 24

a scientist studying respiration in algae observes that glycolysis has occurred but the KC is not active. what would be the most likely cause?

1. lack of NADH
2. lack of FADH2
3. lack of acetyl coA
4. lack of ATP
5. lack of pyruvate

Answer 24

3. lack of acetyl coA

Question 25

you obtain white bacterial colonies on a plate containing X gal. this suggests that

1. your gene of interest was successfully inserted into bacterial plasmid
2. your gene of interest was unsuccessfully inserted into bacterial plasmid
3. your plasmid self-ligated
4. you added the wrong antibiotic

Answer 25

1. your gene of interest was successfully inserted into bacterial plasmid

Question 26

correct the order of steps in the cloning a gene of interest process

1. transform the bacteria
2. mix the digested gene of interest with the digest cloning plasmid
3. incubate the combined DNA fragments with the ligase enzyme
4. use restriction endonuclease to cut the gene of interest and the target DNA
5. spread bacteria on medium containing X gal and ampicillin

Answer 26

4, 2, 3, 1, 5

Question 27

why does a cell shrink

Answer 27

its hypertonic relative to solution, water is leaving the cell so you have high solute outside and low solute inside

Question 28

why does a cell swell

Answer 28

its hypotonic relative to solution, water is entering the cell so you have high solute inside and low solute outside

Question 29

To what does the term stroma refer?

Select one:

a. The cytochrome system in the membranes of the thylakoids.
b. The double membrane of the chloroplast.
c. A stack of thylakoid membrane structures.
d. A flattened disk or sac in the chloroplast.
e. The central fluid-filled space of the chloroplast.

Answer 29

e. The central fluid-filled space of the chloroplast.

Question 30

Which sentence best describes the process of competitive inhibition?

Select one:

a. The inhibitor binds to a site other than the active site of the enzyme and blocks enzyme activity indirectly.
b. The products of the reaction block the active site of the enzyme.
c. The substrate and cofactors compete for the active site.
d. The inhibitor binds to and directly blocks the active site of the enzyme.

Answer 30

d. The inhibitor binds to and directly blocks the active site of the enzyme.

Question 31

How many acetyl CoA molecules could result from 100 glucose molecules? Assume all aspects of cellular respiration are working properly.

Select one:

a. 1000
b. 100
c. 200
d. 50

Answer 31

c. 200

Question 32

In biological systems, the equation C6H12O6 + 6 O2 → 6 CO2 + 6 H2O represents:

Select one:

a. The oxidation of glucose.
b. The Calvin Cycle.
c. Photosynthesis.
d. A one reaction metabolic process

Answer 32

a. The oxidation of glucose.

Question 33

A “passive” membrane transport protein:

Select one:

a. can move a molecule ‘up’ a gradient if a membrane potential exists.
b. is most likely to involve a ‘carrier’ type transport mechanism.
c. can only transport a molecule ‘down’ a gradient.
d. will require a direct source of energy for the transport to occur.

Answer 33

c. can only transport a molecule ‘down’ a gradient.

Question 34

NADP+ + 2e- + 2H+ → NADPH. How does this reaction (the production of NADPH) contribute to ATP synthesis by chemiosmosis?

Select one:

a. The creation of NADPH removes a proton from the stroma, strengthening the proton gradient.
b. NADPH moves electrons to higher energy levels thus increasing their potential energy.
c. NADPH transfers an electron to ATP synthase thus providing energy to power the pump.
d. NADPH is oxidized in the Calvin Cycle and the energy used to create ATP.

Answer 34

a. The creation of NADPH removes a proton from the stroma, strengthening the proton gradient.

Question 35

what are the components of a photoreceptor

Answer 35

a pigement molecule bound to a protein

Question 36

light represents only a very narrow region of the electromagnetic spectrum. however, it is used as the dominant for of electromagnetic radiation used in biology. this is because light can excite electrons within molecules without…

Answer 36

.. destroying them

Question 37

bioluminescence requires

Answer 37

ATP

Question 38

give one distinguishing factor between an eye and the eyespot of Chlamydomonas reinhardtii

Answer 38

an eye can generate an image while the eyespot can sense light

Question 39

for a photon of light to be used by an organism, the photon must be

Answer 39

absorbed