Unit Three - Enzymes

Question 1

What is the function of an enzyme? (2)

Answer 1

1. Speed up the rate of a chemical reaction
2. By lowering the activation energy

Question 2

Why can enzymes be reused over and over again? (2)

Answer 2

AFTER A CHEMICAL REACTION

1. Enzymes are not changed or used up
2. Only a small amount is needed to catalyze numerous rxns

Question 3

Are enzymes organic and why?

Answer 3

Yes, contain C - H bonds

Question 4

Are enzymes specific? (3)

Answer 4

Yes
1. Each enzyme can only catalyze 1 substance
2. Isomers aren’t interchangeable
3. b/c SHAPE of active site is unique

Question 5

What do enzymes normally end in?

Answer 5

• ase

Question 6

What is another word for reactant in enzyme reactions?

Answer 6

Substrate

Question 7

How can an enzymatic rxn be anabolic? (3)

Answer 7

1. Endergonic & Synthesis Rxn
2. Substrate is the Raw Material
3. Bonds & larger molecules are formed

Ex: Dehydration Synthesis, Photosynthesis

Question 8

What is the enzymatic reaction called when it is endothermic?

Answer 8

Anabolic

Question 9

What makes an enzymatic reaction catabolic? (2)

Answer 9

1. Exergonic & Breakdown Rxn
2. Bonds & large molecules are broken down (into smaller building blocks)

Ex: Cellular Respiration & Hydrolysis

Question 10

What is the enzymatic reaction called when it is exothermic?

Answer 10

Catabolic

Question 11

Definition of Optimum Temperature

Answer 11

Temp. at which enzymes function at max. rate
(37°C)

Question 12

Definition of Active Site (3)

Answer 12

1. Site where substrate & enzyme touch
2. Activates to create unstable bonds that need to be stabilized
3. Enabling the catabolic & anabolic reactions

Question 13

What are the three factors that determines whether the enzyme and substrate is compatible?

Answer 13

1. Opposite Charges
2. Shape
3. Active Site Configuration

Question 14

Definition of Induced Fit (2)

Answer 14

1. When substrate binds to the activation site
2. Enzyme slightly changes shape to fit substrate
   (Like a handshake!)

Question 15

Definition of Competitive Inhibition (4)

How, Competes For, Result

Answer 15

1. Substance mimics substrate’s shape
2. Competes for binding site
3. Blocks substrate from binding to AS
4. Decreases enzyme activity & reaction

Question 16

Definition of Noncompetitive Inhibition (3)

Definition, effect

Answer 16

1. Inhibitor binds to allosteric site
2. Enzyme’s shape is changed due to induced fit
3. Substrate cannot bind w/ altered activation site

Question 17

Noncompetitive Inhibition Analogy

Read Through

Answer 17

Someone (noncompetitive inhibitor) comes along and bends the keyhole out of shape. A key (substrate) might still fit in, but it can’t turn to unlock the door (catalyze the reaction).

Question 18

Definition of the ES Complex

Answer 18

Substrate is binded to Enzyme

Question 19

What is Acidic?

PH Level & Contains

Answer 19

pH Level: 1 - 6.9
Contains more H+
Contains less OH -

Question 20

What’s Basic?

PH Level & Contains

Answer 20

pH Level: 7.1- 14
Contains less H+
Contains more OH -

Question 21

What’s Neutral?

PH Level & Contains

Answer 21

pH Level: 7
H+ = OH -

Question 22

What happens to the enzyme when the temperature increases past optimum temperature and decreases past optimum temperature? (5)

Decrease, Increase, Paragraph

Answer 22

Decreases: Metabolic Reactions Slow Down
Increases: Enzyme Denatures, Ceasing Function

1. Changed Shape = Changed Function
2. In secondary structure, breaks H - Bonds
3. In tertiary structure, breaks H - Bonds, Disulfide Bonds, Ionic Bonds & Hydrophobic Interactions
4. In quaternary structure, breaks all bonds as shown above
5. Enzyme can’t combine w/ substrate

Question 23

What happens to the enzyme when the pH level increases past the optimum pH level and decreases past the the optimum pH level?

Answer 23

It denatures, so it will not perform its enzymatic reactions

1. Changed Shape = Changed Function
2. In secondary structure, breaks H - Bonds
3. In tertiary structure, breaks H - Bonds, Disulfide Bonds, Ionic Bonds & Hydrophobic Interactions
4. In quaternary structure, breaks all bonds as shown above
5. Enzyme can’t combine w/ substrate

Question 24

Why can’t the enzyme function well when it the pH level and temperature changes?

(HINT: EXPLAIN HOW SHAPE CHANGES AND HOW IT CHANGES THE FUNCTION) (5)

Answer 24

1. Changed Shape = Changed Function
2. In secondary structure, breaks H - Bonds
3. In tertiary structure, breaks H - Bonds, Disulfide Bonds, Ionic Bonds & Hydrophobic Interactions
4. In quaternary structure, breaks all bonds as shown above
5. Enzyme can’t combine w/ substrate

Question 25

How do you know where to locate the optimum temperature in a "function" graph and a "substrate concentration" graph?

Answer 25

Function: Peak SC: Right before the line flattens

Question 26

Definition of Substrate Concentration (5) | Definition, Result, Explain

Answer 26

1. Fixed amount of enzyme but increasing amount of substrate 2. Rxn rate increases as SC increases 3. Enzyme will be saturated with substrates (more production of products) 4. Fully saturated enzymes don't need more substrates 5. Rate will no longer inrease & and level off

Question 27

Definition of Enzyme Concentration and Explain What Happens (3) | Definition, Result, Explain

Answer 27

1. Fixed amount of substrate but increasing amount of enzymes 2. Increases rxn rate as EC increase 3. If all substrates are already binded to an enzyme, increasing enzyme won't increase rate

Question 28

What's an analogy about why increasing substrate and enzyme concentration will not speed up the reaction if it's already fully saturated? | Read Through

Answer 28

When you first add more raw goods (substrates), the machines (enzymes) can process them faster and produce more products because there’s more work to be done. However, if you keep adding raw goods but don't increase the number of machines, the machines will eventually reach their maximum capacity. At this point, each machine is working as fast as it can, so adding more raw goods doesn’t increase production—there aren’t enough machines to process the extra material. Similarly, if you add more machines (enzymes) but don’t have enough raw goods (substrates), some machines will sit idle, and the reaction won’t speed up. The production rate levels off when all machines are fully occupied, and no additional raw goods or machines can increase the output without increasing the other.

Question 29

Definition of Coenzymes (3) | Structure, Function

Answer 29

1. Organic molecule attatches to an enzyme 2. Required for enzyme function 3. Allows Substrate to bind & necessary for rxn to occur

Question 30

Definition of Cofactors (3)

Answer 30

1. Metal Ions attatch to enzyme (non - protein helpers) 2. Attach to Enzyme 3. Allows Substrate to Bind & Rxn to occur Ex: Hemoglobin allows oxygen to attach to the blood

Question 31

Function of Inhibitors

Answer 31

Slow the rate of enzyme catalyzed reactions

Question 32

Definition of Irreversible Inhibitors (3) | Definition & Result

Answer 32

1. Forms a covalent bond at active site 2. Permanently blocks the substrate 3. ENDS reaction

Question 33

Definition of Reversible Inhibitor (3) | Definition, Result, How to Overcome

Answer 33

1. Forms a temporary bond at active site 2. Slows reaction rate 3. Effects can be overcome by increasing substrate concentration

Question 34

Definition of Metabolic Pathways | Read Through

Answer 34

1. A series of enzyme-catalyzed reactions in a cell 2. Convert substrates to products

Question 35

Definition of the Allosteric Enzyme (3)

Answer 35

1. Enzyme that regulates its own activity 2. By the binding of non - competitive inhibitors at the allosteric site 3. Changes shape of the enzyme (effectively allowing the enzyme to "self-regulate" in response to the cellular environment) Enzymes that have shapes that can be altered by the binding of "signal" molecules to their surfaces

Question 36

Definition of Feedback Inhibition (4) | Definition, How & Why

Answer 36

1. End product of metabolic pathway acts as an inhibitor 2. Turns the reaction on/off 3. Inhibits enzyme involved in initial stages 4. Maintain sbalance by preventing overproduction & waste of resources

Question 37

Why does enzyme activity increase when pH increases? (4) | Read Through

Answer 37

1. PH can change charge of the active site 2. b/c AA can lose or gain H+ based on the pH 3. When pH is at optimal value 4. Active Site will be correctly ionized

Question 38

Why does enzyme activity increase when temperature increases? (3)

Answer 38

1. Increase in molecule speed 2. Increase in molecule collisions, overcoming activation energy 3. More ES complex will form

Question 39

Is exergonic or endergonic reaction spontaneous? Why? (2)

Answer 39

1. Exergonic 2. No need for an input of energy, occurs naturally

Question 40

Definition of Activator and Inhibitor in terms of an allosterically regulated enzyme

Answer 40

Activator: Turns on the reaction (still binds to the non - active site) Inhibitor: Turns off the reaction

Question 41

HOW do coenzymes and cofactors assist enzyme function? (3)

Answer 41

1. Stabilizes 3D shape 2. Maintains Active Sites 3. Assists in the binding of ES

Question 42

Definition of Hydrolase

Answer 42

Enzyme that splits molecules through usage of water

Question 43

In data, how do competitive inhibitors affect chemical reactions?

Answer 43

Data shows it reduces the concentration of the enzyme

Question 44

What's the lock and key theory for enzymes? | Read Through

Answer 44

Enzyme = Lock: The enzyme has a specific active site (like a lock). Substrate = Key: The substrate has a shape that fits perfectly into the enzyme's active site (like a key).