Ch. 6 - Energy and Metabolism

Question 1

What is energy?

Answer 1

The capacity to do work?

Question 2

What is work?

Answer 2

Force x Distance

Question 3

What are two kinds of energy?

Answer 3

1) Kinetic energy

2) Potential energy

Question 4

What is Kinetic energy?

Give an example.

Answer 4

The energy of motion

A boulder rolling down a cliff.

Question 5

What is potential energy?

Give an example.

Answer 5

Stored energy.

A boulder on the edge of a cliff.

Question 6

What forms can energy take?

Answer 6

• Mechanical
• Heat
• Sound
• Light
• Chemical
• Radioactivity

Question 7

Why is heat a good way to measure energy?

Answer 7

Because all form of energy can be converted to heat.

Question 8

What is thermodynamics?

Answer 8

The study of energy.

Question 9

What is heat?

Answer 9

The energy derived from the random motion of molecules.

Question 10

What is the unit of heat used in biology?

Answer 10

The kilocalorie.

Question 11

How many calories are in 1 kilocalorie?

Answer 11

1000 calories.

Question 12

What is a calorie?

Answer 12

The amount of heat required to raise one gram of water 1 degree Celsius.

Question 13

What is a unit of energy that is used in physics?

Answer 13

Joule.

Question 14

What happens to a molecule during oxidation?

Answer 14

A molecule loses an electron.

Question 15

What happens when a molecule is reduced?

Answer 15

A molecule gains an electron.

Question 16

What are redox reactions?

Answer 16

The pairing of oxidation/reduction reactions; they always occur together.

Question 17

What do the laws of thermodynamics explain?

Answer 17

How energy changes occur in the universe.

Question 18

How many laws of thermodynamics are there?

What are they?

Answer 18

2

1st law of thermodynamics
-Energy cannot be created or destroyed, it can only be changed from one form to another.
2nd law of thermodynamics
-The entropy in the universe is always increasing.

Question 19

What is entropy?

Answer 19

A measure of disorder; as energy is used, more and more of it changes to heat.

Question 20

What increases and decreases entropy?

Answer 20

Chemical bonds reduces.

Heat energy increases.

Question 21

What is free energy?

Answer 21

The amount of energy that is available to do work.

Question 22

What changes the amount free energy in a cell?

Answer 22

Chemical reactions.

Question 23

What determines the free energy in a cell?

Answer 23

Depends on heat and chemical energy.

Question 24

What are endergonic reactions?

Answer 24

Reactions that require energy to start.

Question 25

What are exergonic reactions?

Answer 25

Reactions that increase in entropy of the system and can happen spontaneously.

Question 26

What is activation energy?

Answer 26

The energy reactions require to destabilize chemical bonds and start exergonic reactions.

Question 27

What is a catalyst, and what does it do?

Answer 27

An enzyme that lowers the activation energy for the reaction occur.

Speed up chemical reactions.

Question 28

What are enzymes considered?

Answer 28

Biological catalysts.

Question 29

What do enzyme names usually end with?

Answer 29

-ase

Question 30

What certain areas do enzymes have?

Answer 30

active sites.

Question 31

What is a substrate?

Answer 31

The reactants that bind to the enzyme at the active site.

Question 32

What is the enzyme-substrate complex?

Answer 32

The act of a substrate binding to the active site.

Question 33

What is the 4 step process of the enzyme-substrate complex?

Answer 33

1) Substrate (reactants) approach enzyme
2) Substrate binds to the enzyme, and the enzyme changes shape leading to induced fit between the enzyme and substrate.
3) Reactions are catalyzed
4) The products are released and the enzyme returns to starting form.

Question 34

What are multi-enzyme complexes?

Answer 34

Enzymes that are associated together and catalyze similar reactions.

Question 35

What are factors that affect enzyme activity?

Answer 35

1) Temperature
2) pH
3) Inhibition

Question 36

What are ribozymes?

Answer 36

RNA catalysts.

Question 37

How does temperature affect enzyme activity?

Answer 37

Enzyme activity usually increase with temperature until a maximum is reached, and activity stops.

Question 38

How does pH affect enzyme activity?

Answer 38

Enzymes have a tolerance range usually of pH 6-8.

Enzymes in the stomach function at a pH of 2.

Question 39

How does inhibition affect enzyme activity?

Answer 39

Any substance that binds to an enzyme and lower its activity.

Question 40

What are two kinds of inhibition?

Answer 40

1) Competitive

2) Non-Competitive

Question 41

When does competitive inhibition occur?

Answer 41

When the inhibitor wants to bind to the same active site as the substrate, preventing the substrate from binding to the active site causing it to be clogged.

Question 42

When does non-competitive inhibition occur?

Answer 42

When the inhibitor binds to an allosteric site, changing the site of the active site, and preventing the target substrate from binding to the active site.