Proteins

Question 1

Amino Acid

Answer 1

A monomer that will join with other amino acids to form a protein

Question 2

Dipeptide

Answer 2

Two amino acids bonded together via a peptide bond

Question 3

Polypeptide

Answer 3

Many amino acids bonded together via peptide bonds

Question 4

Protein

Answer 4

A combination of polypeptides

Question 5

Amine Group

Answer 5

-NH2, a basic group where the amino part of amino acid comes from

Question 6

Carboxyl Group

Answer 6

-COOH, an acidic group where the acid part of amino acid comes from

Question 7

R Group

Answer 7

A side group that can be comprised of different chemical groups

Question 8

Secondary Structure

Answer 8

The arrangement of the primary structure when considering hydrogen bonds.

This forms either an alpha helix or a beta pleated sheet

Question 9

Alpha Helix

Answer 9

A helix shape that can be formed when considering a polypeptide’s secondary structure

Question 10

Beta Pleated Sheet

Answer 10

A bent v-shaped structure that can be formed when considering a polypeptide’s secondary structure

Question 11

Tertiary Structure

Answer 11

The overall 3D shape of the polypeptide chain, considering all types of bonds; hydrogen bonds, ionic bonds and disulphide bridges. This results in a compact structure

Has hydrophobic interactions between non polar sections.

Question 12

Quarternary Structure

Answer 12

The 3D shape of multiple polypeptide chains combined into one complex molecule. This also considers external associated non-proteins

Question 13

Prosthetic Groups

Answer 13

Associated non-proteins which affect the quarternary structure of a protein

Question 14

Process of the Biuret Test

Answer 14

Add 2cm^3 of the sample with an equal volume of sodium hydroxide.

Add a few drops of very dilute copper(II) sulphate (0.05%) and mix.

A positive test turns purple, a negative test remains blue.

Question 15

Fibrous Proteins

Answer 15

Serve a structural function

Support and protect tissues such as collagen

Question 16

Globular Proteins

Answer 16

Carry out a metabolic function

(enzymes, antibodies, transport proteins)

Spherical & Tightly folded

Question 17

Primary Structure of Collagen

Answer 17

An unbranched polypeptide chain

Question 18

Secondary Structure of Collagen

Answer 18

Very tightly wound, an alpha helix

Question 19

Tertiary Structure of Collagen

Answer 19

Winds into another large helix

Question 20

Quarternary Structure of Collagen

Answer 20

Made up of three polypeptide chains with the same tertiary structure, wound together in a rope shape

Question 21

Uses of Collagen

Answer 21

Fibrous protein

In hair, as part of tendons

Question 22

What can break ionic bonds?

Answer 22

Change in pH

Question 23

What are disulfide bonds between?

Answer 23

Cysteine amino acids

Question 24

Competitive Inhibitors

Answer 24

Compete with substrate for active site

Have a SIMILAR shape as substrate

Blocks the active site so no reaction can take place

Inhibitor is not permanently bound to active site

The greater the concentration of inhibitor the slower the rate of reaction

Question 25

Non Competitive Inhibitors

Answer 25

Bind to the enzyme AWAY from its active site

This causes the active site to change shape

Substrate molecule cannot bind

Enzyme cannot function

Question 26

What is the primary structure of a polypeptide?

Answer 26

Sequence of amino acids

Question 27

Examples of proteins with quarternary structure.

Answer 27

Haemoglobin

Antibodies