BIO 1081 Mock Exam 2 Edited

University of Cincinnati, Dr. Mosley, Spring 2024

Which of the following statements is

true about hypertonic solutions?

a. They have a higher solute

concentration than the cell.

b. They cause cells to swell.

c. They have no effect on cells.

d. They have a lower water

concentration than the cell.

a. They have a higher solute

concentration than the cell.

How does the fluid mosaic model

explain the structure of the plasma

membrane?

a. It describes the membrane as

a rigid structure with

proteins embedded in a fluid

lipid matrix

b. It portrays the membrane as

a dynamic structure with

proteins and lipids free to

move laterally

c. It suggests that the

membrane is composed of a

static arrangement of

proteins and carbohydrates

d. None of the above

b. It portrays the membrane as

a dynamic structure with

proteins and lipids free to

move laterally

In which type of reaction is free

energy released, and products have

less free energy than the reactants?

a. Endergonic

b. Exergonic

c. Anabolic

d. Catabolic

b. Exergonic

What type of inhibitor binds to an

enzyme at a site other than the

active site, altering the enzyme's

conformation and activity?

a. Competitive inhibitor

b. Noncompetitive inhibitor

c. Allosteric inhibitor

d. Covalent inhibitor

b. Noncompetitive inhibitor

Which enzyme catalyzes the

conversion of glucose to glucose-6-

phosphate in the first step of

glycolysis, trapping glucose in the

cell?

a. Phosphofructokinase

b. Hexokinase

c. Aldolase

d. Isomerase

b. Hexokinase

The sodium-potassium pump

exchanges sodium ions for

potassium ions at a ratio of:

a. 1:1

b. 2:2

c. 3:2

d. 2:3

c. 3:2

During each cycle of the sodium-potassium pump, how many phosphate groups are hydrolyzed

from ATP?

a. 0

b. 1

c. 2

d. 3

b. 1

What is the main driving force for

the movement of water through a

selectively permeable membrane in

osmosis?

a. Concentration of water

b. Concentration of solutes

c. Voltage difference

d. Temperature

b. Concentration of solutes

Which type of transport is

responsible for moving large

particles or macromolecules into the

cell by forming vesicles?

a. Active transport

b. Endocytosis

c. Exocytosis

d. Facilitated diffusion

b. Endocytosis

Which type of regulation occurs

when a product of a metabolic

pathway inhibits an enzyme earlier

in the pathway?

a. Positive Feedback

b. Negative Feedback

c. Allosteric Regulation

d. Competitive Inhibition

b. Negative Feedback

What is the main function of the

phosphofructokinase enzyme in

glycolysis?

a. To phosphorylate fructose1,6-bisphosphate

b. To reduce NAD+ to NADH

c. To catalyze the conversion of

pyruvate to acetyl-CoA

d. To pump protons into the

mitochondria

a. To phosphorylate fructose1,6-bisphosphate

Which enzyme catalyzes the

dephosphorylation of

phosphoenolpyruvate (PEP) to

pyruvate in glycolysis?

a. Hexokinase

b. Phosphofructokinase

c. Pyruvate kinase

d. ATP synthase

c. Pyruvate kinase

Which of the following statements

about enzymes is true?

a. Enzymes are consumed

during chemical reactions.

b. Enzymes alter the

equilibrium of a chemical

reaction.

c. Enzymes lower the activation

energy of a reaction.

d. Enzymes only work at or near

neutral pH levels.

c. Enzymes lower the activation energy of a reaction.

The Gibbs free energy change for a

chemical reaction is -30 kJ/mol.

What can be said about the

spontaneity of the reaction?

a. The reaction is nonspontaneous.

b. The reaction is spontaneous.

c. The reaction is at

equilibrium.

d. The reaction has no change

in energy.

b. The reaction is spontaneous.

Which gas is produced as a byproduct of the Krebs cycle?

a. Oxygen

b. Carbon dioxide

c. Nitrogen

d. Hydrogen

b. Carbon dioxide

According to the second law of

thermodynamics, what does the

term "entropy" refer to?

a. The energy available to do

work

b. The measure of disorder or

randomness in a system

c. The total energy of a closed

system

d. The amount of heat energy

produced during a reaction

b. The measure of disorder or

randomness in a system

Which statement about membrane

fluidity is accurate?

a. Saturated lipids increase

membrane fluidity

b. Lower temperature

decreases membrane fluidity

c. Higher temperature

decreases membrane fluidity

d. Unsaturated lipids make the

membrane less fluid

b. Lower temperature

decreases membrane fluidity

What is the role of NADH in

glycolysis?

a. It is a substrate for the

reaction.

b. It carries electrons to the

electron transport chain.

c. It is used to produce glucose.

d. It is a waste product.

b. It carries electrons to the

electron transport chain.

What is the primary role of the Krebs

cycle in cellular respiration?

a. To produce ATP directly

b. To convert glucose to

pyruvate

c. To transport electrons to the

electron transport chain

d. To break down fats for

energy

c. To transport electrons to the

electron transport chain

In pyruvate oxidation, which of the

following is a product of the

metabolic pathway per glucose

molecule?

a. 2 ATP

b. 3 CO2

c. 2 NADPH

d. none of the above

d. none of the above

Coupled transport in cell

membranes involves the

simultaneous movement of two

different substances. Which of the

following best describes symport, a

type of coupled transport?

a. Both substances move in the

same direction, both into or

out of the cell.

b. One substance moves into

the cell while the other

moves out of the cell.

c. Both substances move in

opposite directions, either

into or out of the cell.

d. Only one substance is

transported, while the other

is unaffected

a. Both substances move in the

same direction, both into or

out of the cell.

Which protein complex/es in the ETC

is/are responsible for oxidizing

NADH to NAD+ and FADH2 to FAD,

respectively?

a. Complex II only

b. Complex II and III

c. Complex I and II

d. Complex II and IV

c. Complex I and II

During the electron transport chain,

where is the highest proton

concentration found, which

contributes to the proton motive

force?

a. In the mitochondrial matrix

b. In the cytoplasm

c. In the intermembrane space

d. In the nucleus

c. In the intermembrane space

Which of the following is NOT a

product of glycolysis?

a. Pyruvate

b. ATP

c. NADH

d. Carbon dioxide

d. Carbon dioxide

Pyruvate oxidation results in the

conversion of pyruvate into:

a. Glucose

b. Lactic acid

c. Acetyl-CoA

d. Ethanol

c. Acetyl-CoA

Eukaryotic flagella are composed of

what protein?

a. Dynein

b. Kinesin

c. Tubulin

d. Flagellin

c. Tubulin

What is the first enzyme involved in

pyruvate oxidation that catalyzes the

decarboxylation of pyruvate?

a. Pyruvate dehydrogenase

b. Pyruvate carboxylase

c. Pyruvate kinase

d. Pyruvate decarboxylase

a. Pyruvate dehydrogenase

Which protein is associated with

microfilaments and muscle

contraction?

a. Keratin

b. Actin

c. Tubulin

d. Myosin

b. Actin

Pyruvate oxidation is a critical linker

step between which two major

metabolic pathways in cellular

respiration?

a. Glycolysis and the citric acid

cycle

b. Glycolysis and the electron

transport chain

c. Glycolysis and fermentation

d. Glycolysis and

gluconeogenesis

a. Glycolysis and the citric acid

cycle

How many carbon atoms are present

in each molecule of acetyl CoA?

a. 1

b. 2

c. 3

d. 4

b. 2

What is true about fermentation?

a. It’s a type of anaerobic

respiration

b. It’s a process that produces

large amounts of ATP

c. It’s a metabolic pathway that

does not require oxygen

d. It’s a process that occurs in

the mitochondria

c. It’s a metabolic pathway that

does not require oxygen

What is the main function of

Complex IV in the electron transport

chain?

a. To transfer electrons to

oxygen

b. To generate ATP

c. To convert glucose to

pyruvate

d. To produce NADH

a. To transfer electrons to

oxygen

Which of the following is true about

fermentation?

a. It is anaerobic respiration.

b. It does not utilize the ET

c. Pyruvate serves as the

electron acceptor.

d. It is not part of glycolysis.

c. Pyruvate serves as the

electron acceptor.

In the electron transport chain, the

flow of electrons generates a flow of

protons across a membrane. What is

this flow of protons called?

a. Electron current

b. Proton current

c. Chemiosmotic gradient

d. ATP synthesis

c. Chemiosmotic gradient

What is the function of

desmosomes?

a. Tight junctions that prevent

water leakage between cells

b. Gap junctions that allow

small molecules to pass from

cell to cell

c. Anchoring junctions that

hold cells together during

movement

d. Channels for communication

between adjacent cells

c. Anchoring junctions that

hold cells together during

movement

How many carbons are lost as

carbon dioxide in one turn of the

citric acid cycle (Krebs cycle)?

a. 0 carbons

b. 1 carbon

c. 2 carbons

d. 3 carbons

c. 2 carbons

The coenzyme FAD is first present in

which of the following?

a. Calvin cycle

b. ETC

c. Citric acid cycle

d. Photosynthesis

c. Citric acid cycle

What is the function of ATP synthase

in the electron transport chain

(ETC)?

a. To transport electrons

between complexes

b. To pump protons across the

inner mitochondrial

membrane

c. To convert ADP to ATP using

the proton motive force

d. To reduce oxygen to form

water

c. To convert ADP to ATP using

the proton motive force

What is one role of microtubules in

the cell?

a. Muscle contraction

b. Cell migration

c. Chromosome separation

during cell division

d. Cell structure and stability

c. Chromosome separation

during cell division

Which of the following compounds

can serve as an allosteric regulator

of pyruvate dehydrogenase in cell

respiration?

a. Coenzyme A

b. Citrate

c. NADH

d. Glucose-6-phosphate

c. NADH

How many total molecules of ATP

are produced by substrate-level

phosphorylation for each glucose

that enters glycolysis?

a. 2 ATP

b. 3 ATP

c. 4 ATP

d. 6 ATP

d. 6 ATP

In glycolysis, which enzyme

generates ATP through substrate-level phosphorylation?

a. Hexokinase

b. Phosphofructokinase

c. Pyruvate kinase

d. Aldolase

c. Pyruvate kinase

Short answer:

What is the name of the only component of the ETC that is NOT a protein?

Ubiquinone