Chapter 8: Metabolism

Question 1

Name the two types of reactions

Answer 1

Catabolic - breakdown pathways, releases energy

Anabolic - biosynthetic pathways, requires energy

Question 2

CHE & ADE

Answer 2

Catabolic
Hydrolysis
Exergonic

Anabolic
Dehydration
Endergonic

Question 3

What is Potential Energy?

Answer 3

Stored energy waiting to be used

Question 4

What is Kinetic Energy?

Answer 4

Energy that an object has because of its movement

Question 5

First law of thermodynamics

Answer 5

Energy cannot be created nor destroyed

Question 6

Second law of thermodynamics

Answer 6

Energy transformations are not 100% efficient

Question 7

Which do you think contains the most potential energy?
A. Glucose 
B. Sucrose 
C. A phospholipid
D. A triacylglycerol

Answer 7

D. It has more bonds, therefore it’s more efficient to store a lot of energy.

Question 8

Exergonic reactions ________ energy.

Answer 8

release

Question 9

In terms of spontaneity, exergonic reactions are ________.

Answer 9

Spontaneous

Question 10

Endergonic reactions ______ energy.

Answer 10

require

Question 11

In terms of spontaneity, endergonic reactions are __________.

Answer 11

Non spontaneous

Question 12

Which of the following is an endergonic reaction?

A. Synthesis of a polypeptide from amino acids
B. Diffusion of oxygen molecules across a plasma membrane
C. Digestion of starch into its component glucose molecules
D. Formation of hydrogen bonds between water molecules

Answer 12

A. Synthesis of a polypeptide is dehydration, which is endergonic.

Question 13

What is energy coupling?

Answer 13

1. Energy transferred from catabolic -> anabolic

2. Energy transferred from exergonic -> endergonic

Question 14

How do you make sure energy is not lost during a transfer?

Answer 14

Through the energy carrier, ATP.

Question 15

Where is energy stored in ATP?

Answer 15

In the covalent bonds between the phosphates

Question 16

When ATP is hydrolysized, the energy release powers an __________ reaction.

Answer 16

Endergonic

Question 17

What are enzymes?

Answer 17

• catalysts that speed a reaction
• not consumed by the reaction
• are reusable
• many of them are proteins

Ending in -ase

Question 18

In terms of Activation Energy, exergonic reactions have _____ energy overall than when they started.

Answer 18

less

Question 19

In terms of Activation Energy, endergonic reactions have _____ energy overall than when they started.

Answer 19

more

Question 20

Enzymes _______ the activation energy.

Answer 20

lower

Question 21

True or False

Enzymes decrease the energy of the products to make endergonic reactions exergonic reactions.

Answer 21

False. Enzymes do not change the energy of products or reactants.

Question 22

Explain the 5 steps of how enzymes do their work.

Answer 22

1. Substrates enter the active site.
2. Substrates are held in the active site due to their shape.
3. Substrates undergo intermolecular forces in the substrate complex and are converted into products.
4. The products (substrates) now have a different shape and are released.
5. The active site is now available for new substrates.

Question 23

Inhibitors

What is normal binding?

Answer 23

When the substrate goes directly to the active site of an enzyme without any interference.

Question 24

Inhibitors

What is competitive inhibition?

Answer 24

When a competing substrate goes into the active site and the original substrate doesn’t bind.

Question 25

Inhibitors

What is noncompetitive inhibition?

Answer 25

When a noncompetitive inhibitor binds to a different active site on the same enzyme. This changes the shape of the active site for the original substrate and it cannot bind.