Unit 1: Proteomics & Protein Structure 3 Flashcards Preview

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Flashcards in Unit 1: Proteomics & Protein Structure 3 Deck (21)
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1
Q

A ligand is a

A

substance that binds to proteins

2
Q

Binding sites on a protein will be complementary to the

A

ligand

3
Q

What is a nucleosome?

A

DNA wrapped around eight histones

4
Q

What is a histone?

A

Eight proteins surround by a nucleosome

5
Q

To maximise space how are nucelosomes arranged?

A

Stacked on top of each other

6
Q

Some proteins binding sites are specific to cetrain sequences of DNA as a result

A

when bound can stimulate or inhibit transcription

7
Q

When a ligand binds to a protein the

A

conformation changes

8
Q

A conformational change in a protein can either

A

activate or deactivate it

9
Q

Describe induced fit in enzymes

A

When the correct substrate binds to the enzyme a temporary change in the conformation occurs increasing the binding and interaction with the substrate

10
Q

An allosteric enzyme is an enzyme that can

A

have its activity altered by a ligand called a modulator

11
Q

In allosteric enzymes, where to modulators bind?

A

At secondary binding sites

12
Q

Negative modulators reduce the enzyme’s

A

affinity for the substrate

13
Q

Positive modulators increase the enzyme’s affinity for the

A

substrate by altering the conformation of the active site so it fits the substrate better

14
Q

End product inhibition is an example of

A

negative feedback control

15
Q

Describe end product inhibiton

A

The final product of a series of enzyme reactions interacts with an allosteric enzyme inhibiting it and thus ending the reaction.

16
Q

Competitive Inhibiton example, methanol poisioning. Explain

A

Methanol is oxidised to formaldehyde and formic acid. Ethanol compeitively inhibits the oxidation of methanol, meaning the oxidation of methanol is slow and therefore does not accumulate causing no harm.

17
Q

Deoxyhaemoglobin has a

A

low affinity for oxygen

18
Q

When one molecule of oxygen binds to one of the four haem groups in a haemoglobin molecule it

A

increases the affinity of the remaining three groups to bind oxygen.

19
Q

Oxyhaemoglobin loses its ability to bind to oxygen as each

A

haem group releases oxygen

20
Q

What is the curve of the oxygen dissociation curve like?

A

A sigmoid

21
Q

Under what conditions would haemoglobin struggle to bind to oxygen?

A

Sickle cell anaemia, thalassaemia and high altitude