Chapter 8: Energy and Enzymes for Exam 2

Question 1

The reactant acted on by the enzyme

Answer 1

Substrate

Question 2

Are prosthetic groups organic or inorganic?

Answer 2

Both

Question 3

Regulation that can either activate or inhibit activity

Answer 3

Allosteric regulation

Question 4

Does being spontaneous mean the rxn occurs quickly?

Answer 4

No

Question 5

How is enzyme function regulated?

Answer 5

Tightly regulated through competitive inhibition and allosteric regulation

Question 6

What often act as enzyme inhibitors and can have irreversible binding?

Answer 6

Toxins and poisons

Question 7

What 3 things would enzymes not function without?

Answer 7

Cofactors, coenzymes, and prosthetic groups

Question 8

How do enzymes catalyze rxns?

Answer 8

By lowering activation energy

Question 9

What types of drugs inhibit enzymes?

Answer 9

HIV medications, ACE inhibitors (HBP), Prilosec (H+/K+ ATPase), penicillin

Question 10

What are enzymes?

Answer 10

Proteins or sometimes RNA which act as catalysts and speed up rxns

Question 11

Factors that affect enzyme activity

Answer 11

Temp and pH

Question 12

What is induced fit?

Answer 12

When the binding of the substrate causes the enzyme to slightly change shape

Question 13

How specific do substrates need to be to fit an active site?

Answer 13

Very specific. Only very specific ones can fit the active site

Question 14

What is the optimal pH for enzymes in humans?

Answer 14

Depends on where they are found

Question 15

What do enzymes often do?

Answer 15

Catalyze a series of related rxns

Question 16

Regulatory molecule binds away from the active site and causes change in shape

Answer 16

Allosteric regulation

Question 17

What does sarin gas do?

Answer 17

Binds to the active site of acetylcholinesterase and acts as a competitive inhibitor that causes ACh to stay in synapse and continue to signal eventually causing death

Question 18

Six steps of an enzyme catalyzing a rxn

Answer 18

1. ) Substrates enter active sites
2. ) Substrates are held in active site by weak interactions
3. ) Active site can lower activation energy and speed up a rxn
4. ) Substrates are converted to products
5. ) Products are released
6. ) Active site is available for new substrate molecules

Question 19

Region of the enzyme that actually binds the substrate

Answer 19

Active site

Question 20

What are coenzymes?

Answer 20

Organic molecules like NAD, B vitamins, CoQ, folic acid that work with enzymes to make them function properly

Question 21

How does penicillin work?

Answer 21

Blocks the active site of enzyme necessary for cell wall formation in bacteria. Humans don’t need or have that enzyme so it doesn’t effect us

Question 22

How specific is the rxn catalyzed by a particular enzyme?

Answer 22

Enzymes are very specific

Question 23

What are prosthetic groups?

Answer 23

Molecules tightly bound to enzymes like retinal (vitamin A), metal ions, and vitamins that work with enzymes to make them function properly

Question 24

What does feedback inhibition prevent the cell from doing?

Answer 24

Prevents the cell from wasting energy to make excess product

Question 25

Three things that work with enzymes

Answer 25

Cofactors, coenzymes, and prosthetic groups

Question 26

Optimal pH for enzymes in stomach?

Answer 26

1-3

Question 27

Are enzymes consumed in rxns?

Answer 27

No

Question 28

How are metabolic pathways regulated?

Answer 28

Feedback inhibition

Question 29

What happens as you inc temp?

Answer 29

Inc rxn rate until a certain temp and then the enzymes will begin to denature

Question 30

These are usually proteins but can also be RNA

Answer 30

Enzymes

Question 31

What happens to enzymes at the end of a rxn?

Answer 31

They are not consumed and can catalyze again

Question 32

How do enzymes work?

Answer 32

They lower the activation energy (Ea)

Question 33

How does the enzyme shape change during induced fit?

Answer 33

The enzyme shape changes to wrap the substrate

Question 34

Regulatory molecules resembles the substrate and binds to the active site to block the actual substrate

Answer 34

Competitive inhibition

Question 35

Examples of prosthetic groups

Answer 35

Retinal (vitamin A), metal ions, and vitamins

Question 36

Which group is basically part of the enzyme?

Answer 36

Prosthetic groups

Question 37

What is feedback inhibition?

Answer 37

End product of a pathway can bind to an enzyme that acts earlier in the pathway to inhibit it so it doesn't waste energy making excess product

Question 38

Is regulatory binding usually reversible?

Answer 38

yes

Question 39

Optimal pH for enzymes in blood?

Answer 39

Around 7

Question 40

What are cofactors?

Answer 40

Inorganic ions like Fe, Zn, Mg that work with enzymes in order to make them function properly

Question 41

Where is activation energy required in the progress of a rxn

Answer 41

Transition state

Question 42

What does changing the shape of the enzyme during induced fit do?

Answer 42

Brings chemical groups of active site into optimal position to catalyze rxns

Question 43

Examples of coenzymes

Answer 43

NAD, B vitamins, CoQ, folic acid

Question 44

What is activation energy?

Answer 44

Reactants absorb energy from their surroundings to reach state where bonds can change

Question 45

What is optimal temp for enzymes?

Answer 45

Depends on where the enzyme will function. 98.6F in humans, etc.

Question 46

When do proteins function best?

Answer 46

Under specific conditions

Question 47

What does it mean for a rxn to be spontaneous?

Answer 47

It occurs without the need of energy input

Question 48

Regulatory molecules can leave the enzyme to turn it off and on

Answer 48

Allosteric regulation

Question 49

How do starting molecules need to change for a rxn to occur?

Answer 49

They usually need to be contorted into an unstable form

Question 50

Steps in the progress of a rxn?

Answer 50

Reactants to transition state to products

Question 51

Examples of cofactors

Answer 51

Fe, Zn, Mg

Question 52

How do enzymes lower activation energy?

Answer 52

Act as a docking site to bring reactants together in proper orientation (bring substrates to correct positioning), stretch reactants toward transition-state form stressing and bending chemical bonds, provide a microenvironment more favorable to a particular rxn, and participate directly in the chemical rxn