Unit 5 - Cell Energy Flow

Question 0

What are the two components (“steps”) of metabolism?

Answer 0

Catabolism = breakdown reactions
Anabolism = synthesis reactions

Question 1

What is metabolism?

Answer 1

The total of all chemical reactions that take place within a cell

Question 2

What is the difference between Kinetic Energy and Potential Energy?

Answer 2

KE = energy in motion
PE = stored energy

Question 3

What are the two laws of thermodynamics?

Answer 3

1. Energy cannot be created or destroyed, only converted from one form to another
2. In any chemical reaction there will always be some energy which is lost in the form of heat.

Question 4

What process is an example of biological entropy?

Answer 4

Cellular respiration

Question 5

What process is an example of biological enthalpy?

Answer 5

Photosynthesis

Question 6

What is a metabolic pathway?

Answer 6

A stepwise sequence of reactions in cells, with specific enzymes catalytic each step

Question 7

What are 2 benefits of metabolic pathways?

Answer 7

1. Conservation of energy

2. Many products can be produced from a single original substance

Question 8

What is a catabolic pathway?

Answer 8

The breakdown of large biological molecules, usually with the release of energy (I.e. Cellular respiration)

Question 9

What is an anabolic pathway?

Answer 9

Construction of biological molecules using energy (I.e. Photosynthesis)

Question 10

Give at least 4 characteristics of an enzyme

Answer 10

1. Catalysts for biological reactions
2. Most are proteins
3. Lower activation energy
4. Increase rate of reaction
5. Activity lost if denatured
6. Are not used up in reaction

Question 11

What 2 parts does an enzyme consist of?

Answer 11

1. Apoenzyme

2. Coenzyme

Question 12

What is an apoenzyme and what does it do?

Answer 12

It’s a protein that acts as the active site of the enzyme. It is also the functional unit of the enzyme and is created in the cell

Question 13

What is a coenzyme and what does it do?

Answer 13

It’s a non-protein that activates the apoenzyme, and is obtained through the diet (not made in cells). It’s usually a vitamin and it participates in the reaction by contributing/accepting atoms or electrons

Question 14

Describe the Lock + Key Model of enzyme action

Answer 14

1. Enzyme binds to a substrate in the active site (only certain substrates can fit in the active site)
2. Amino Acid R-Groups in the active site help the substrate bind
3. Enzyme-substrate complex is formed
4. Substrate reacts to form product
5. Product is released (enzyme is not used up)

Question 15

What is the Induced-Fit Model of Enzyme Action and how is it different from the Lock and Key Model?

Answer 15

The Induced Fit Model uses enzymes that are flexible, not rigid. The enzyme and the active site adjust their shape to bind to the substrate. The Induced Fit Model also increases the range of substrate specificity

Question 16

What are the 4 factors that affect Enzyme Action?

Answer 16

1. Temperature
2. Substrate Concentration
3. pH level
4. Radiation

Question 17

How does temperature affect enzyme action?

Answer 17

1. Little activity at low temperature
2. Rate increases at higher temperature
3. Most activate at optimum temperature (37deg for humans)
4. If temperature is too high, activity is lost with denaturation.

Question 18

How does substrate concentration affect enzyme action?

Answer 18

1. ^concentration increases rate of reaction
2. Max activity teaches when all of enzyme is in use
3. After saturation point, reactions remains flat because increasing amounts of substrate must wait before they can fit with their enzyme (enzyme concentration is constant)

Question 19

How does pH affect enzyme action?

Answer 19

1. Max activity at optimum pH
2. R-groups of amino acids have proper charge
3. Most lose activity in low/high pH

Question 20

How does radiation affect enzyme action?

Answer 20

It denatures the enzyme and prevents enzyme action t

Question 21

What do enzyme inhibitors do?

Answer 21

1. Cause a loss of catalytic activity
2. Change the protein structure of an enzyme
3. May be competitive or non-competitive
4. Some effects are irreversible

Question 22

What do competitive inhibitors do?

Answer 22

1. Has a structure similar to substrate
2. Occupies the active site
3. Competes with substrate for active site
4. Has effect reversed by increasing substrate concentration

Question 23

What’s a non-competitive inhibitor and what does it do?

Answer 23

1. Does not have structure like substrate
2. Bonds to the enzyme but not the active site
3. Changes shape of enzyme and active site
4. Substrate cannot fit altered active site
5. No reaction occurs
6. Effect is not reversed by adding more substrate

Question 24

What is an example of a non-competitive substrate?

Answer 24

Heavy metals, drugs

Question 25

What is thyroxin?

Answer 25

A modified amino acid contains iodine that is produced in the thyroid gland

Question 26

What does thyroxin do?

Answer 26

Increase the metabolic rate by:

1. Increasing synthesis of enzymes
2. Increasing heart rate
3. Increasing breathing rate

It also creates more body heat