Biology: Proteins

Question 1

Primary structure

Answer 1

Sequence of amino acids in the proteins polypeptide chain.

Question 2

Secondary structure

Answer 2

Twists and folds that cause alpha helices and beta-pleated sheets in the proteins shape. Hydrogen bonds hold these in shape.

Question 3

Tertiary structure

Answer 3

The 3D shape of the protein, folds caused by hydrophobic interactions between R groups of different amino acids.

Question 4

Quaternary structure

Answer 4

Bonds between multiple polypeptide chains in some proteins.

Question 5

Amino acid structure

Answer 5

Carbon atom attached to a hydrogen atom, an amine group, a carboxylic acid group and an R group. The R group varies between different amino acids.

Question 6

Bonds formed between two amino acids

Answer 6

Dipeptide bonds

Question 7

When to amino acids join together

Answer 7

Condensation reaction

Question 8

Bi-product of a condensation reaction

Answer 8

Water

Question 9

Globular protein structure

Answer 9

Has a tertiary (3D) structure. Hydrophilic R groups on the outside make the protein soluble in water.

Question 10

Fibrous protein structure

Answer 10

Remains as a long chain, therefore there is o tertiary structure, only primary and secondary. They are able to form cross-links with other polypeptide chains. Thus increasing strength.

Question 11

Globular protein function

Answer 11

Used in metabolic reactions (enzymes) as they can dissolve in the watery cytoplasm. Their 3D shape allows them to bind to other substances/molecules, e.g., haemoglobin binding to oxygen.

Question 12

Fibrous protein function

Answer 12

Used in structures, as the cross links provide extra strength.

Question 13

Globular proteins examples

Answer 13

Enzymes
Antibodies
Haemoglobin and myoglobin

Question 14

Fibrous proteins examples

Answer 14

Keratin in skin and hair.

Collagen in skin, tendons, cartilage and blood vessels.