Ch. 6

Question 1

State the first law of thermodynamics.

Answer 1

1. Energy can not be created or destroyed

2. But energy can be changed from one form to another

Question 2

State the second law of thermodynamics.

Answer 2

1. The law of entropy
2. Energy can not be changed from one form to another without the loss of usable energy
3. Entropy is the name for calculating how much unusable energy is present in a system
4. The more usable energy there is left in a system after chemical reactions, the more efficient the system.

Question 3

Define potential energy.

Answer 3

1. Stored energy

Question 4

Give examples of potential energy stored in biological important molecules.

Answer 4

Glucose and ATP

Question 5

Define kinetic energy.

Answer 5

1. The energy of motion

Question 6

What is entropy?

Answer 6

1. The measure of the disorganization of a system.

2. Entropy is the name for calculating how much unusable energy is present in a system

Question 7

Does the universe move towards less entropy or more entropy?

Answer 7

The universe is moving towards more entropy.

Question 8

When molecules move from being less complex and less organized to being more complex and more molecules, what happens to entropy? Is this associated with exergonic or endergonic reactions? Is this a positive of negative (triangle)G?

Answer 8

1. More organized= less entropy = not going to happen without the use of energy to fight the law of increasing disorder(increasing entropy)
2. Endergonic reaction: cells capture some of the energy released
3. Positive (triangle)G

Question 9

What are the three parts of ATP?

Answer 9

1. The nucleotide base adenine
2. The 5 carbon sugar ribose
3. 3 phosphate groups

Question 10

What happens at the active site of an enzyme?

Answer 10

1. The part of the enzyme where the substrate binds

2. The active site will be a pocket in the enzymes surface,and it’s often just a small part of the overall molecule.

Question 11

What is a reactant? (Substrate)

Answer 11

Substances that participated in a reaction

A+B -> C+D it is (A+B)

Question 12

What are products?

Answer 12

1. The substances that form as a result of a reaction.

A+B -> C+D its the (C+D)

Question 13

Define the energy of activation.

Answer 13

The energy that must be added to a system in order for the reaction to occur.

Question 14

What does an enzyme do to the energy of activation of a reaction?

Answer 14

1. Enzymes lower the energy of activation

2. Enzymes, therefore reduce the energy need for a reaction to begin.

Question 15

What happens when an enzyme is denatured?

Answer 15

It’s when extreme temp. And the wrong levels of pH happen, enzymes are no longer active and cannot function.

Question 16

What happens to a reaction rate when an enzyme is denatured?

Answer 16

Since amino acid “R” group interaction determines 3D structure, anything changes this enough will keep the enzyme from functioning correctly.

Question 17

Can low pH (acidic) or high pH (basic) solution cause denaturation?

Answer 17

Yes, to acidic or to basic will cause enzyme denaturation.

Question 18

Can a high temperature denature an enzyme?

Answer 18

Yes because high heat ruptures bonds in protein structure.

Question 19

What is the basic difference between a cofactor and a coenzyme?

Answer 19

Cofactor- an inorganic or a non-protein organic molecule necessary at the activation site for correct function of the enzyme.
Coenzyme- a non-protein compound that is necessary for the functioning of an enzyme.

Question 20

Which cofactor and coenzyme include metal ions and which include vitamins?

Answer 20

Vitamins
1. The vitamin niacin is part of the structure of NAD+ (nicotinamide adenine dinucleotide)
2. The vitamin riboflavin (B2) is part of the structure of FAD (Flavin adenine dinucleotide)
Metal Ions
Copper
Zinc
Iron

Question 21

Describe non-competitive enzyme inhibition.

Answer 21

The enzyme has two sites that bind other molecules
1. One site is the active site
2. A different site binds the inhibitor
Without the inhibitor, the active site is the correct shape to accept and bind the substrate
When the inhibitor is bound to its site, the active site changes shape and the substrate won’t fit= no reaction/ no product

Question 22

Describe competitive enzyme inhibition.

Answer 22

1. The enzyme has one site, the active site
2. The inhibitor is not the substrate, but can fit in the active site
3. When the inhibitor is present, it fills the active site and the substrate won’t fit.
4. No substrate in active site= no product

Question 23

What is oxidation?

Answer 23

When a metal loses electrons

The loss of the whole hydrogen atom

Question 24

What is reduction?

Answer 24

When oxygen gains electrons

The gain of the whole hydrogen atom