Core component 1 - Proteins Flashcards Preview

Eduqas A level Biology - Year 1 > Core component 1 - Proteins > Flashcards

Flashcards in Core component 1 - Proteins Deck (20)
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1
Q

What elements are proteins made up of?

A

Carbon, hydrogen, oxygen, nitrogen (and sometimes sulfur and phosphorus)

2
Q

What happens during the formation of a dipeptide?

A

The amino group reacts with a carboxyl group (H and OH) eliminating water and forming a peptide bond between the C of the carboxyl group and the N of the amino group

3
Q

What is the primary structure of a protein?

A

The order of the amino acids in the polypeptide chain.

4
Q

What bonds are found in the primary structure of proteins?

A

They are linked by peptide bonds only.

5
Q

What is the secondary structure of a protein?

A

The shape of that the polypeptide chain makes as a result of hydrogen bonding. This causes the chain to be twisted into a 3-D shape.

6
Q

What are the 2 common shapes of a protein with a secondary structure?

A

A spiral shape call an alpha-helix or less commonly a beta-pleated sheet.

7
Q

What is the tertiary structure of proteins?

A

The alpha helix and the beta pleated sheet can be further folded to give a more complex 3D structure. This folding can also make it more compact.

8
Q

What bonds can occur in the tertiary structure of a protein?

A

Hydrogen and ionic bonding, disulfide bridges and hydrophobic interactions.

R-groups may interact to form bonds which help to maintain the structure’s 3D shape.

9
Q

What is the quarternary structure of a protein?

A

More than one polypeptide chain bonded together

10
Q

Why do some polypeptide chains combine with others?

A

Because some are not functional unless they are in combination.

11
Q

What is the structure of haemoglobin?

A

It contains two alpha helix polypeptides and two beta-pleated sheets (4 polypeptide chains) each with a haem group in the centre (this is a non-protein iron containing group)

12
Q

Are fibrous proteins soluble or insoluble in water?

A

Insoluble

13
Q

What is the structure of a fibrous protein?

A

Polypeptide in parallel sheets with cross-linkages forming long fibres.

14
Q

What are the uses of fibrous proteins?

A

Strength, structure and support

Collagen in tendons

15
Q

What are the uses of globular proteins ?

A

Enzymes, antibodies, plasma proteins, hormones

16
Q

Are globular proteins insoluble or soluble in water?

A

Soluble

17
Q

What is the structure of a globular protein?

A

They are compact and folded into spherical molecules.

18
Q

What is the test for proteins?

A

It is called the Biuret test. You add biuret reagent. The sodium hydroxide and the copper (ii) sulphate in this reacts to make copper hydroxide which interacts with the peptide bonds to make biuret which is purple.

19
Q

What is the structure of a collagen molecule?

A

Three polypeptide chains bounded together in a swirl joined by hydrogen bonds.

20
Q

How many amino acids are there and how are they different?

A

20 and they differ by their R groups

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