1. A cell must expend energy to produce a concentration gradient. ______________

Question

1. A cell must expend energy to produce a concentration gradient.
__________________

True

False

1 points   

QUESTION 2

A(n) closed system does not exchange energy with its surroundings.
__________________

True

False

QUESTION 3

A(n) exergonic reaction results in a net gain of free energy.
__________________

True

False

QUESTION 4

According to the second law of thermodynamics, the amount of usable energy available
to do work in the universe ____ over time.

decreases

exponentially increases

increases

crashes

stays constant

1 points   

QUESTION 5

An enzyme raises the activation energy of the reaction it catalyzes.
__________________

True

False

1 points   

QUESTION 6

At a constant temperature and pH, the rate of an enzymatically catalyzed reaction is inversely proportional to the enzyme concentration.
__________________

True

False

1 points   

QUESTION 7

Energy that is useable and organized is classified as having ____.

low energy

low entropy

high entropy

low enthalpy

high energy

1 points   

QUESTION 8

The transfer of electrons from one compound to another is equivalent to ____ transfer.

energy

enzymatic

heat

oxygen

phosphorus

1 points   

QUESTION 9

The direction of an exergonic reaction can best be describe as moving:

from higher to lower free energy.

from higher to lower absolute temperature.

from lower to higher absolute temperature.

from lower to higher free energy.

from higher to lower entropy.

1 points   

QUESTION 10

The cell maintains a ratio of ATP to ADP that is at the equilibrium point.
__________________

True

False

1 points   

QUESTION 11

Most vitamins are coenzymes.
__________________

True

False

1 points   

QUESTION 12

Identify which compound has been reduced: XH2 + NAD+ X + NADH + H+.

X

XH2

NADH

NAD+

H+

1 points   

QUESTION 13

In order for a cell to maintain a high degree of order, it must constantly:

produce energy.

use energy.

release energy.

increase energy.

destroy energy.

1 points   

QUESTION 14

In what method do competitive inhibitors inhibit biochemical reactions?

Competitive inhibitors denature the enzyme.

Competitive inhibitors increase the concentration of enzyme.

Competitive inhibitors increase the concentration of substrate.

Competitive inhibitors reduce the concentration of enzyme.

Competitive inhibitors reduce the concentration of substrate.

1 points   

QUESTION 15

Many bacterial infections are treated with drugs, such as penicillin and sulpha drugs, that ____ the bacterium’s enzyme activity.

inhibit

promote

decrease

stabilize

accentuate

1 points   

QUESTION 16

Select the phosphorylation reaction.

glucose + fructose sucrose + H2O

glucose + ATP glucose-P + ADP

glucose-P + fructose sucrose + Pi

glucose + glucose maltose

sucrose + H2O glucose + fructose

1 points   

QUESTION 17

Suppose the free energy of the reactants is greater than the free energy of the products. Such a reaction is referred to as a(n) ____.

exergonic reaction.

endergonic reaction.

activation reaction.

entropic reaction.

catabolic reaction.

1 points   

QUESTION 18

The maintenance of a high ATP to ADP ratio within cells ensures that the:

hydrolysis of ADP to ATP will be an energy releasing reaction.

hydrolysis of ATP to ADP will be strongly endergonic.

hydrolysis of ATP to ADP will be strongly exergonic.

hydrolysis of ADP to ATP will be strongly exergonic.

conversion of ADP to ATP will proceed spontaneously.

1 points   

QUESTION 19

Which best describes a catabolic reaction?

It involves the breakdown of life sustaining processes within cells.

It involves the breakdown of large organic molecules to simple building blocks.

It involves the building up of complex organic molecules from simple building blocks.

It involves the anabolic production of complex molecules.

It involves the expenditure of energy.

1 points   

QUESTION 20

Which best describes the energy of activation?

The enzymes required to lower a reaction's rate

A type of endergonic reaction

The catalysts needed to raise a reaction's rate

The energy required to break existing bonds

A type of exergonic reaction

a.

decreases

b.

exponentially increases

c.

increases

d.

crashes

e.

stays constant

Explanation / Answer

Answer:

1). True

A cell must expend energy to produce a concentration gradient. Becuase work is done to produce this ored, a concentration gradient is a form of potential energy

2). False

closed system  energy  not  its surroundings.

3). True

Exergonic reactions: A reaction that results in a net release of free energy (decrease in G, negative G), occur spontaneously - The magnitude G represents the amount of work the reaction can do. (though some is lost as heat) - potential energy is released, products are of lower free energy than reactants

4). A. Decreases

According to second law of thermodynamics, the amount of usable energy available to do work in the universe decreases overtime.

5). Flase

Catalysts lower the activation energy for reactions. The lower the activation energy for a reaction leads to the faster the reaction rate. Thus enzymes speed up reactions by lowering activation energy. Many enzymes change shape when substrates bind.

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