Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

FLC > Enzymes > Flashcards

Enzymes Flashcards

1
Q

Which functions are carried out by enzymes?

A
  • Digestion
  • Blood Clotting
  • Defence / Immune system activation of complement
  • Movement
  • Nerve Conduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where are enzymes located/found in the body?

A
  • Intracellularly

- Secreted extracellularly

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

What are the consequences of enzyme defects?

A

Defects in enzymes cause disease

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

Is the formation of an enzyme-substrate complex an active or passive process?

A

Active process - requires energy

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

Give an example of an antibiotic

A

Penicillin

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

Which enzyme catalyses movement in the body?

A

ATPase catalyses the muscle actomyosin contraction mechanism

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

Name a few examples of types of enzymes found in the body

A
  • Proteases
  • Nucleases
  • Kinases
  • Polymerases
  • Synthases
    etc.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain how the antibiotic Penicillin works

A

Inhibits cell wall synthesis in bacteria causing it to burst

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

How are enzymes useful in drug use?

A

Enzymes can be used as drug targets

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

What compounds do enzymes aid digestion of?

A

Carbohydrates, Proteins and fats

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

In what ways can we alter factors to make catalysis easier?

A
  • Constrain substrate movement
  • Stabilise +ve and -ve (transition state)
  • Provide a lower Ea route
  • Strain certain bonds => breakage easier
  • Use co factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the consequence of Phenylketonuria to patients?

A

Results in decreased metabolism of the amino acid phenylalanine to Tyrosine due to inheriting defected
phenylhydroxylase enzyme
- lots of phenylalanine -> converted into toxic by products
- affect brain maturation

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

Explain what is meant by the Induced Fit Model

A

Active site alters it shape to become complementary to its substrate

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

What is the basic reaction path of substrate binding?

A

E + S <=> ES => EP => E + P

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

How does compartmentation regulate enzymes in the cell?

A

Each enzyme has a short amino acid sequence that is a targeting signal telling organelles whether it can enter the cell or not

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

Give 3 examples of diseases caused by enzyme defects

A
  1. Phenylketonuria -
  2. GSD (Glycogen storage disease) -
  3. Tay-sachs Disease -
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Give an example of an anti-inflammatory agent

A

Aspirin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Explain what Tay Sachs disease is

A

Absence of hexosaminidase-A (Hex-A) enzyme causes GM2 ganglioside (lipid) to accumulate
abnormally in cells, especially causing progressive damage to nerve cells in brain
- patients unable to form membrane lipid cerebreside (significant to brain)”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why does enzyme activity eventually plateau?

A

There is a limit to the number of substrates a single enzyme can bind to in a given time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How can enzyme active sites be observed?

A

Xray Crystallography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Explain how the drug aspirin works as an anti inflammatory agent

A

Inflammation caused by cyclooxygenases and messenger prostaglandin molecule
Aspirin blocks prostaglandin production and cyclooxygenases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is compartmentation?

A

The concentrating and separating of enzymes and metabolites within organelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the consequence of covalent modifications of enzymes?

A

Change the enzyme shape and therefore its functional activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is Vmax?

A

Maximum velocity (rate) at which the enzyme catalyses a reaction. Occurs when all enzyme active sites are saturated with substrates

25
How is enzyme activity regulated in the body?
- Compartmentation - Covalent Modification - Allosteric regulation
26
What is allosteric regulation?
Regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site
27
How can Vmax and Km be used to determine reaction rate?
Rate of reaction = 1/Vmax + km/Vmax
28
How can we increase reaction rate?
Increase substrate concentration
29
What is a GSD (glycogen storage disease)?
Metabolic disorder caused by enzyme deficiencies affecting glycogen synthesis / breakdown or glycolysis
30
Give an example of an enzyme that causes blood clotting
Thrombin catalyses the formation of fibrin clots
31
Give an example of a common enzyme covalent modification?
De/Phosphorylation of enzymes
32
What is an active site?
3D celft/cavity that binds substrates using electrostatic, hydrophobic, hydrogen bonding and Van der Waals interactions
33
How is phenylketonuria treated?
Patients consume a low phenylalanine diet
34
List some properties of allosteric enzymes
- Multi sub unit complexes - Regulatory and catalytic sites on different sub units - involved in feedback inhibition of metabolic pathways
35
What is Vmax dependent on?
The rate at which an enzyme can process a substrate molecule
36
What is an enzyme?
Proteins that are biological catalysts which speed up the rate of reaction by providing an alternative reaction route with a lower activation energy
37
Give an example of an anticancer drug
Methotrexate
38
Which enzymes are involved in nerve conduction?
Membrane ion pumps for sodium and calcium ions
39
What is Km?
Michaelis Constant | The concentration of substrate when enzyme reaches 1/2Vmax
40
How are enzymes categorised?
Enzymes are categorised by the type of reaction they catalyse
41
Explain how anticancer drug Methotrexate works
Methotrexate is a Folate analogue (inhibits Folate action) Folic acid significant in DNA/RNA synthesis Methotrexate blocks enzymes using Folate as co factor - inhibiting DNA synthesis
42
List some functional properties of enzymes
- Increase reaction rate (>10bn fold) - Specific to substrates - Remain unchanged during reactions - Doesn't alter reaction equilibrium (catalyses reaction in forwards and backwards direction) - Decreases activation energy
43
What is a medicinal use of proteases?
Therapeutic drug targets
44
Why is an acylenzyme able to form from chymotrypsin?
Chymotrypsin has a very reactive serine which attacks the peptide to form the acyl protein product
45
What is the function of proteases?
Hydrolyse peptides by selectively cleaving particular peptide bonds
46
What makes the chymotrypsin serine so reactive?
The serine has a catalytic triad that makes the OH group increase in electronegativity - therefore is very reactive
47
How stable are the proteins present in our bodies?
They are chemically stable but not thermodynamically stable
48
What is a catalytic triad?
Group of 3 amino acids found in active sites fo certain proteases involved in catalysis
49
How do serine proteases identify which bond to cleave?
Serine proteases have a high specificity for the peptide bond they hydrolyse
50
Name some common proteases
- serine - cysteine - aspartyl - metalloproteinases
51
Outline how the acyl Enzyme intermediate is formed during peptide bond cleavage
1. Catalytic triad and electronegativity converts OH into very -ve charge 2. O interferes with C-N (peptide) bond 3. Ester intermediate formed (acyl enzyme) 4. Water hydrolyses the intermediate 5. Peptide bond is cleaved
52
Explain what is meant by the hydrophobic pocket?
A binding site containing mainly hydrophobic amino acids | e.g. binding site for aromatic side chains in chymotrypsin substrates
53
Which peptide bonds does Trypsin specifically hydrolyse?
"Has specificity for peptide bonds on Arginine and Lysine (+ve charged) - forms electrostatic attractions to -ve pocket
54
Which substrates does the elastase cleave?
Only cleaves small substrates as the pocket is small - only small residues are able to fit
55
How is the 3D structure of proteins conserved by Serine proteases?
With a charge relay system
56
Where is the protein Elastase found in the body?
In the lungs
57
Where is Trypsin proteins found?
In the liver
58
Which is chymotrypsin's area of specificity?
Chymotrypsin cleaves aromatic residues due to hydrophobic pocket: - Phenylalanine - Tryptophan - Tyrosine
59
What is the role of ATP synthase enzyme?
Forms ATP by converting energy from H+ by moving them down their diffusion gradient in chemiosmosis Proton current rotates synthase to form ATP

FLC (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions