Lecture 9 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What are reactants?

A

The starting molecules of a chemical reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are products?

A

The final molecules of a chemical recation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the free energy charge tell us?

A

Whether or not a reaction occurred spontaneously or not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a living systems free energy?

A

energy that can do work when temperature and pressure are uniform, as in a living cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is delta G

A

Free-Energy Change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an exergonic reaction?

A

energy released spontaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do enzymes do to metabolic recations?

A

They speed them up by lowering energy barriers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Thermodynamics does not tell us about the ____ of a reaction.

A

speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a catalyst?

A

a chemical agent that speeds up a reaction without being consumed by the reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an enzyme? Example?

A

a catalytic protein (occasionally RNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What occurs during chemical reactions?

A

bond breaking and bond forming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is activation energy (Ea)?

A

The initial energy needed to start a chemical reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the activation energy often consist of?

A

thermal energy that the reactant molecules absorb from their surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens at the transition state?

A

The reactants become unstable and start to go downhill

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How is the change in free energy affected by enzymes?

A

enzymes have no effect on it; they only hasten reactions that would occur eventually

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List the 3 characteristics of all enzymes.

A

-increase speed of reacton by lowering Ea
-Are not altered by reactions
-Can catalyze multiple rounds of reactions

17
Q

List the 3 characteristics specific to enzymes.

A

-Highly specific for reactants and reactions they catalyze
-Perform highly specific catalysis (few side products)
-Can be regulated

18
Q

What is a substrate?

A

The reactant that an enzyme acts on

19
Q

What is an enzyme-substrate (ES) complex?

A

when an enzyme binds to its substrate

20
Q

The reaction catalyzed by each enzyme is _______.

A

very specific.

21
Q

What is the active site?

A

The region on the enzyme where the substrate binds.

22
Q

How much enzyme do you need in a reaction and why?

A

very small amounts because they are used repeatedly (catalytic)

23
Q

Enzyme shape is not ___ .

A

static

24
Q

What are the 4 ways an active site can lower an Ea barrier?

A

-orienting substrates correctly
-straining substrate bonds
-providing a favorable microenvironment
-covalently bonding to the substrate

25
Q

What are the three ways an enzymes activity can be affected?

A

-general environmental factors, such as temperature and pH
-chemicals that specifically influence the enzyme
-substrate concentration

26
Q

What are cofactors?

A

Nonprotein enzyme helpers; may be organic or inorganic

27
Q

What is a coenzyme?

A

an organic cofactor including vitamins

28
Q

What is enzyme kinetics?

A

Measuring the rate if reactions under varying conditions

29
Q

What can enzyme kinetics tell you?

A

the catalyst mechanism, its role in metabolism, how its activity is controlled, how a drug might alter it

30
Q

What is V_max in enzyme kinetics?

A

-saturation point for a particular amount of enzyme
-maximal reaction rate when substrate is not limiting

31
Q

What is K_m in enzyme kinetics?

A

-substrate concentration at which reaction velocity is half maximal
-inversely related to enzyme affinity

32
Q

What do competitive inhibitors do?

A

bind the active site of an enzyme, competing with the substrate

33
Q

What so non-competitive inhibitors do?

A

bind to another part of the enzyme, making the active site less effective

34
Q

List some examples of inhibitors?

A

Toxins, poisons, pesticides, and antibiotics

35
Q
A