proteins

Question 1

what is the monomer of a polypeptide chain?

Answer 1

amino acids

Question 2

what are some examples of proteins in the body

Answer 2

hormones, haemoglobin, antibodies, enzymes, structural components

Question 3

what do all amino acids contain?

Answer 3

a central carbon atom, an amine group (NH2), a carboxylic acid group (COOH) and an R group which varies between types

Question 4

via what reaction do amino acids join?

Answer 4

condensation reaction

Question 5

draw a dipeptide and label the peptide bond

Answer 5

…

Question 6

what is the most simple amino acid and draw it

Answer 6

glycine, R group is just H

Question 7

what is the primary structure of protein?

Answer 7

the order and number of amino acids in the polypeptide chain

Question 8

what is the secondary structure of protein?

Answer 8

the shape that the polypeptide chain folds or coils into, either an alpha coil or a beta pleated sheet. these are stabilised by hydrogen bonds between oxygen and hydrogen

Question 9

what is the tertiary structure of protein?

Answer 9

the folding of the polypeptide chain into a 3d shape. this is when the secondary structure allows the R groups to be close enough to interact

Question 10

what are the four types of tertiary interactions in protein?

Answer 10

1- disulphide bonds in cystine
2- hydrogen bonds in R group
3- hydrophillic/hydrophobic
4- ionic bonds (electrostatically)

Question 11

what is the structure of a globular protein?

Answer 11

compact, spherical, and water soluble. Formed when proteins fold into their tertiary structure (when R groups are close enough to interact). This is specifically due to the hydrophobic/hydrophilic interactions. The hydrophobic R groups on the amino acids avoid aqueous environments whilst the hydrophilic R groups stay outside of the protein. Therefore the proteins are soluble in water.

Question 12

name three types of globular proteins

Answer 12

haemoglobin, insulin, catalase

Question 13

what is a conjugated protein?

Answer 13

any globular protein that contains a non-protein component. e.g. lipoproteins have a lipid component

Question 14

name three examples of fibrous proteins?

Answer 14

keratin, collagen, elastin

Question 15

what is the structure of fibrous proteins?

Answer 15

formed from insoluble long molecules. Contain a high proportion of amino acids with hydrophobic R groups (don’t like water). The variety of amino acids is limited, and the polypeptide chain is often quite repetitive leading to very organised structures. Normally produce long, unfolded and strong proteins.