Enzymes as Biological Catalysts Flashcards

1
Q

What is the function of an enzyme?

A

An enzyme speeds up the rate at which a reaction reaches equilibrium

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2
Q

How do enzymes affect the equilibrium position?

A

They DO NOT affect the equilibrium position of a reaction

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3
Q

What are enzymes composed of?

A

Protein

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4
Q

What is the energy of activation?

A

The energy put into a reaction for that reaction to occur.

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5
Q

How do enzymes affect the energy of activation?

A

Enzymes reduce the activation energy by providing alternative reaction pathways

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6
Q

What is the transition state of a reaction?

A

The transition state is the reaction intermediate species which has the greatest free energy

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7
Q

What may the catalytic activity of enzymes require?

A

Cofactors

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8
Q

What are the two types of cofactors?

A
Metal ions
Organic molecules(coenzymes)
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9
Q

What are tightly bound coenzymes are called?

A

Prosthetic group

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10
Q

What is an enzyme without cofactor is called?

A

Apoenzyme

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11
Q

What is an Enzyme with cofactor is called

A

Haloenzyme

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12
Q

What does symptoms of vitamin deficiencies reflect?

A

Loss of specific enzyme control

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13
Q

What are the two types of vitamin deficiency?

A

Dietary Deficiency

Functional Deficiency

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14
Q

What are the properties of the active site?

A

A cleft or crevice

Contains amino acids essential for catalytic activity

Contains amino acids for highly specific interactions

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15
Q

What are Isozymes?

A

Isozymes are isoforms of enzymes, they catalyse the same reaction but have different properties and structure (and sequence)

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16
Q

What is Haemoglobin composition during embryonic development ?

A

Consists of 2 Theta and 2 Epsilon

protein chains

17
Q

What is Haemoglobin composition during the last trimester of pregnancy?

A

Consists of two 2 alpha chains and 2 gamma chains

18
Q

What is Haemoglobin composition after birth?

A

2 alpha chains and 2 beta chains

19
Q

What causes denaturation of enzymes?

A

Temperature

pH

20
Q

What is the clinical use of Isozymes?

A

Relative amounts of isozymes in blood are useful for diagnostic purposes

21
Q

How can enzymes activity be regulated?

A

Enzymes can be activated or deactivated by phosphorylation

Regulation of enzyme activity by irreversible covalent modification

22
Q

What are Zymogens?

A

Inactive precursors of an enzyme

23
Q

How are Zymogens activated?

A

Irreversibly transformed into active enzymes by cleavage of a covalent bond