Biology answers | Biology homework help

1.

What does ΔG of a metabolic reaction measure?

the net change in free energy during a reaction

the amount of heat energy gained or lost in a reaction

the amount of matter transferred in a reaction

the change in activation energy required in a reaction due to enzyme activity

the activation energy of a reaction

2.

Which of the following does a catalyst change during a chemical reaction?

the free energy of the products

heat

entropy

activation energy

the free energy of the reactants

3.

ATP is not the only molecule that can drive reactions. When ATP is depleted during exercise, muscle cells use phosphocreatine to drive the regeneration of ATP.

Consider the following half reactions:

1. ATP + H2O → ADP + Pi

ΔG = –7.3 kcal/mol

2. Phosphocreatine + H2O → creatine + Pi

ΔG = –10.3 kcal/mol

From these two reactions, calculate the Gibbs free energy of the following coupled reaction, catalyzed by creatine kinase:

Phosphocreatine + ADP → ATP + creatine

ΔG = ?

Which is the correct net Gibbs free energy of the reaction?

ΔG = –3 kcal/mol

ΔG = –17.6 kcal/mol

ΔG = 0 kcal/mol

ΔG = +3 kcal/mol

ΔG = +17.6 kcal/mol

4.

Which source of energy does active transport use?

the regeneration of ATP bound to an active transport pump

the hydrolysis of ATP bound to an active transport pump

the hydrolysis of GTP bound to the active transport pump

the transport of ATP bound to an active transport pump

the transport of GTP bound to an active transport pump

5.

Which is an anabolic process?

protein synthesis

glycolysis

ATP hydrolysis

protein degradation

active transport

6.

The sodium-potassium pump is an active transport pump that uses energy to pump potassium into cells and sodium out of cells. Why is ATP energy required?

to change the shape of the ions

to transfer glucose in the same direction as Na+ ions

to pump the Na+ and K+ ions along their diffusion gradient

to pump the Na+ and K+ ions against their diffusion gradient

for the membrane to change shape

7.

Which definition best describes a cell’s metabolism?

the chemical reactions that break down glucose for energy

the use of ATP as an energy carrier

the energy level that must be overcome for a chemical reaction to move forward

the burning of fat molecules for energy

the sum of all the chemical reactions occurring in an organism

8.

Which reaction can provide the energy needed to run an endergonic reaction?

protein synthesis

photosynthesis

ATP hydrolysis

enzyme catalysis

All answers are correct.

9.

Which process(es) can directly amplify signals in a transduction pathway?

activating adenylyl cyclase

activating kinases

activating phosphatases

activating phospholipase C

All answers are correct.

10.

What happens when protein kinase A (PKA) phosphorylates phosphorylase kinase in the epinephrine signal transduction pathway?

Phosphorylase kinase becomes deactivated, and glucose production is suppressed.

Phosphorylase kinase becomes activated, and glucose production is suppressed.

Phosphorylase kinase becomes deactivated, and glucose production is enhanced.

Phosphorylase kinase becomes activated, and glucose production is enhanced.

None of the answers are correct.

11.

Which is a catabolic process?

glycolysis

ATP synthesis

ion transport

photosynthesis

translation of mRNA into protein

12.

Which reaction does a kinase catalyze in a signal transduction pathway?

binding of a signal molecule to a receptor

production of cAMP

phosphorylation of a target protein

All answers are correct.

None of the answers are correct.