Chapter 6 - Energy & Enzyme

Question 1

Energy

Answer 1

The capacity to do work

Question 2

1st Law of Thermodynamics

Answer 2

Energy cannot be created or destroyed

Question 3

2nd Law of Thermodynamics

Answer 3

Energy tends to disperse spontaneously

Question 4

Free energy

Answer 4

The amount of energy that is available or “free” to do work

Question 5

Endergonic reaction

Answer 5

Converts molecules with lower energy to molecules with higher energy

Question 6

Example of endergonic reaction

Answer 6

Photosynthesis

Question 7

Exergonic reaction

Answer 7

Converts molecules with higher energy to molecules with lower energy

Question 8

Example of exergonic reaction

Answer 8

Aerobic respiration

Question 9

Activation energy

Answer 9

Minimum amount of energy required to start a reaction

Question 10

Functions of activation energy

Answer 10

• breaks down chemical bonds of reactants
• keeps exergonic reactions from starting spontaneously
• brings reactants to a transition state

Question 11

Is activation energy required for both reactions?

Answer 11

Yes

Question 12

Catalyst

Answer 12

Speed reaction rates by lowering activation energy

Question 13

Catalysis

Answer 13

An enzyme allows a reaction to run much faster than it would on its own

Question 14

Substrate

Answer 14

A molecule that is specifically acted upon by an enzyme

Question 15

Enzyme specificity

Answer 15

Occurs because an enzyme’s polypeptide chain folds into one or more active sites

Question 16

Active site

Answer 16

Pocket in an enzyme where substrates react and are converted into products

Question 17

How do the substrates bind to the enzyme?

Answer 17

Binds to their complementary active site in shape, size, polarity, and charge

Question 18

How do enzymes lower their activation energy?

Answer 18

• concentrating substrate molecules
• orienting substrates to favour reaction
• inducing fit between substrate and active site
• excluding water from active site