Enzyme Action and Inhibition Flashcards

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

How does and an enzyme lower the activation energy?

A

An enzyme binds to a substrate and stresses some of its chemical bonds, or binds to two substrates and forces them close together

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

What effect does a lower activation energy have on reaction speed?

A

Reactions are more likely to happen so the reaction rate speeds up.

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

What type of reaction are enzymes involved in which join molecules together?

A

Synthesis anabolic (usually condensation)

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

What type of reaction are enzymes involved in which break molecules apart?

A

Degradation, catabolic (usually hydrolysis)

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

What does the amino acid sequence of an enzyme affect?

A

The shape of the active site

Which amino acids are in the active site.

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

Why are enzymes specific to one substrate or a group of very similar substrate

A

Because of their highly defined structure

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

What is the enzyme which is specific to glucose?

A

Glucokinase

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

What does the enzyme hexokinase work on?

A

Glucose and some other six-carbon sugars

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

What is the effect of the active site having amino acids?

A

The amino acids have an affinity for areas on the substrate molecule.

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

How do the substrate and the enzyme bind?

A

By forming hydrogen and ionic bonds

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

What is the effect of the arrival of the substrate bonding to the active site?

A

Brings about a conformational change in the enzyme.

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

How can an enzyme showing an induced fit lower the activation energy?

A

The reaction becomes more likely as the substrate is under tension.

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

What are the 4 types of enzyme you are expected to know?

A

Proteases (pepsin + trypsin + bromelain)
Nucleases (EcoRI)
ATPases (sodium potassium pump)
Kinases (Adds a phosphate to inactivate glycogen synthesis)

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

What is the action of proteases?

A

Hydrolysis of peptide bonds to break down proteins

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

What is the action of nucleases?

A

Hydrolysis of phosphodiester bonds to break down nucleic acids

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

What is the function of ATPases?

A

Hydrolysis of phosphoester bonds in ATP to form ADP and phosphate

17
Q

What is the function of kinases?

A

Condensation reaction to add a phosphate group to another molecule.

18
Q

How can you find the activity of an enzyme?

A

Using a constant concentration of enzyme and then measuring the initial rate of reaction at different substrate concentrations.

19
Q

What are the two ways an inhibitor can reduce reaction rate

A
  • They can resemble the substrate

- They alter the enzymes shape so that it becomes inactive.

20
Q

What is a competitive inhibitor

A

Similar to the substrate in size, shape and charge pattern

21
Q

How is vMax reached in the presence of a competitive inhibitor?

A

Increasing the substrate concentration will eventually dilute the competitive inhibitor so much that all the enzyme molecules bind to the genuine substrate.

22
Q

Where do non-competitive inhibitors bind to?

A

Another part of the enzyme away from the active site.

23
Q

What do mercury and lead bind to?

A

The -SH groups of cysteines in the protein

24
Q

What is the result of a non-competitive inhibitor?

A

The active site no longer fits the substrate.

25
Q

Why is Vmax reduced with a non-competitive inhibitor?

A

A proportion of the enzymes are inactive.