Problem Set #5- Energy/Thermodynamics

Question 1

Which of the following is an example of potential rather than kinetic energy?

Answer 1

a compressed spring

The compressed spring has stored energy in it. When released, that energy will be converted to kinetic.

Question 2

Which of the following is true of enzymes?

Answer 2

Enzymes increase the rate of chemical reaction by lowering the activation energy.

Question 3

Use the following information to answer the question below.
a enzyme 1 —-> b enzyme 2 —> c enzyme 3
What would happen to the rate of production of D if the concentration of enzyme 1 was increase but the concentration of enzymes 2 and 3 remained constant?

Answer 3

It would stay the same.

The production of A –> B may increase, but unless you increase all 3 enzymes, the concentration would remain the same.

Question 4

What is going on here cooking an egg (biologically speaking of course)?

Answer 4

The increased temperature denatures the proteins in the egg.

Question 5

Free energy decreases and the stability of a system increases during which types of reactions?

Answer 5

Spontaneous

Question 6

A chemical reaction that has a positive ΔG is best described as _____ while one with a negative ΔG is _____?

Answer 6

anabolic, catabolic

Question 7

An enzymatic reaction.
what is D?

Answer 7

Product(s)

Question 8

Mitochondria are found

Answer 8

Only in eukaryotes

Question 9

The most common usable form of energy in a cell is

Answer 9

ATP

ATP (Adenosine Triphosphate) is a more immediate source of energy than glucose because ATP is produced in the cells and its conversion to energy is a single-step process. Whereas glucose first needs to be broken down in order to be used as an energy source.

Question 10

Nearly all enzymes are what kind of biomolecule?

Answer 10

Proteins

Question 11

How will a healthy individual’s ATP production change during a 12-hour fast?

Answer 11

The individual’s ATP production will not change significantly.

During a 12 hour fast glycolysis and respiration should continue to function normally. Therefore, production of ATP would not be altered significantly. Your body should have stores of energy-rich molecules that can be used from glycogen stored in muscles and your liver or fats stored in fatty tissue.

This is for a 12 hour fast for a healthy person

Question 12

Which of the following has the highest entropy?

Answer 12

Water at 100*C

Entropy increases as temperature increases. Therefore it decreases at temperatures decrease. Ice is MUCH more ordered (less entropy) than water. Boiling water (100C) is much LESS ordered, (more entropy).

Question 13

Which of the following statements about anabolic pathways is true?

Answer 13

They consume energy to build up polymers from monomers.

Question 14

Which of the following shows the BEST example for the indicated energy transformation?

Answer 14

Popping (or untying a balloon): potential energy→ kinetic energy

Question 15

Which of the following statements is consistent with the second law of thermodynamics?

Answer 15

A constant input of energy is required to maintain the high level of cellular organization seen in living organisms.

Question 16

Which of the following statements is(are) TRUE regarding energy of systems?

Answer 16

-Living organisms are open systems and, when functioning properly, will never reach equilibrium with their environments (∆G not equal 0).
-Reactions in a closed system will eventually reach equilibrium; ∆G = 0.

Question 17

Which of the following is the best example of an exergonic reaction and what happens?

Answer 17

Respiration, breakdown of glucose

Question 18

According to the first law of thermodynamics:

Answer 18

Energy cannot be created or destroyed.

Question 19

When an enzyme speeds up metabolic reactions,

Answer 19

it decreases the activation energy necessary to begin the reaction.

Question 20

ATP drives endergonic reactions by the process of _________, which is the _________________.

Answer 20

phosphorylation, transferring a phosphate to other molecules

Question 21

Consider the reaction profile for three enzymes, A, B and C. A solution with enzyme C and its substrate is kept at pH 9. If a weak acid is gradually added to it, the activity of enzyme C will most likely:

Answer 21

increase, then eventually decrease as the acid continues to be added.

Question 22

Energy is incorporated into ATP when:

Answer 22

a phosphate group is added.

Question 23

sucrose + H2O = glucose + fructose

Answer 23

sucrose: substrate
sucrase: enzyme
glucose: product
fructose: product

Question 24

Non-competitive inhibition differs from competitive inhibition by

Answer 24

he location that the inhibitor binds to the enzyme.

Question 25

What kind of enzyme regulation is occurring in the figure below? Enzyme 1 has become blocked from being synthesized

Answer 25

Feedback inhibition.