Chapter 3 Study Questions (Part 1)

Question 1

what is free energy?

Answer 1

energy that can be extracted from a molecule to do work

Question 2

what can free energy tell you about a chemical reaction?

Answer 2

exergonic or endergonic

Question 3

what does exergonic reaction mean? (3)

Answer 3

exergonic. free energy is negative. reactants greater than products. catabolic.

Question 4

what does endergonic reaction mean? (3)

Answer 4

free energy is positive. endergonic. products greater than reactants. anabolic.

Question 5

what does free energy is positive mean? (3)

Answer 5

free energy is positive. endergonic. products greater than reactants. anabolic.

Question 6

what does free energy is negative mean? (3)

Answer 6

exergonic. free energy is negative. reactants greater than products. catabolic.

Question 7

what does reactants greater than products mean? (3)

Answer 7

exergonic. free energy is negative. reactants greater than products. catabolic.

Question 8

what does products greater than reactants mean? (3)

Answer 8

free energy is positive. endergonic. products greater than reactants. anabolic.

Question 9

what does anabolic mean? (3)

Answer 9

free energy is positive. endergonic. products greater than reactants. anabolic.

Question 10

what does catabolic mean? (3)

Answer 10

exergonic. free energy is negative. reactants greater than products. catabolic.

Question 11

when do exergonic reactions proceed spontaneously?

Answer 11

when the activation energy barrier is overcome.

Question 12

why is it a good thing that we only extract ~1/3 of the energy from glucose?

Answer 12

you have to burn glucose to get all the energy out of it and that would be lethal to us.

Question 13

define mass action

Answer 13

increasing reactants moves the reaction to the right. increasing products moves the reaction to the left.

Question 14

if ATP is the energy currency of the cell, why doesn’t a cell store chemical energy as ATP?

Answer 14

we can’t! ATP spontaneously hydrolyzes over time

Question 15

define hydrolyze

Answer 15

break down

Question 16

what does ATP hydrolyze into?

Answer 16

ADP and AMP

Question 17

what is the induced fit model of enzyme catalysis, and how does it explain that an enzyme can break a chemical bond without requiring an input of energy? (3)

Answer 17

1. enzyme catalytic site has a shape complementary to its substrate
2. interaction between substrate and catalytic site causes a conformational (shape) change in the catalytic site that breaks bonds
3. substrate is converted into the product and is released from the catalytic site

Question 18

what is the difference between a substrate and a ligand?

Answer 18

S: the reactant, binds to an enzyme

L: interact with receptors, bind to stuff, reversible reaction

Question 19

what is gluconeogenesis?

Answer 19

the creation of new glucose

Question 20

what type of reaction is gluconeogenesis?

Answer 20

reactants lower than products, free energy is positive, endergonic, anabolic.

Question 21

why is the activation barrier a good thing?

Answer 21

otherwise it would be all product, no reactants, and that would be bad

Question 22

are covalent bonds involved with ligands?

Answer 22

no!

Question 23

what is the role of enzymes?

Answer 23

lower the activation energy barrier so that a chemical reaction can occur

Question 24

what is a redox reaction?

Answer 24

involves a transfer of electrons