proteins 1

Question 1

what is an amino acid made up of?

Answer 1

central carbon attached to a H, R, Carboxylic acid group and an amino group

Question 2

what is a codon

Answer 2

a triple base sequence which codes for an amino acid. the aminoacid is determined by the first base

Question 3

what types of amino acid are there and what do they mean?

Answer 3

1- aliphatic-only C and H
2-aromation-contains a cyclic aromatic ring
3-basic- tend to have a positive charge due to an extra NH2
4- acidic-tend to have a negative charge due to an extra COO-

Question 4

what its a peptide bond?

Answer 4

a covalent bond which forms between two adjacent amino acids to form a polypeptide and one molecule of H2O

Question 5

where does the peptide bond form?

Answer 5

in ribosome during translation

Question 6

define primary structure

Answer 6

the sequence of amino acids in a polypeptide chain

Question 7

define secondary structure

Answer 7

the spatial arrangement of amino acid residues which are near each other in a linear sequence.

Question 8

describe the two types of secondary structure

Answer 8

Alpha-helix: telephone wire shape. H-bonds between the H-N and the C=O every 4 amino acid residues.
Beta-pleated sheets: H-bonds between amide groups of linear polypeptide chains

Question 9

define tertiary structure

Answer 9

the spatial arrangement of aminoacid residues which are far away from each other in the polypeptide chain

Question 10

hydrogen bonds

Answer 10

1/20th the strength of a peptide bond
stronger than VDWs
forms with F,O,N

Question 11

VDWs

Answer 11

weak interactions within the tertiary structure.

there are many of them. every 0.3 nm

Question 12

disulphide bridges

Answer 12

between cysteine containing groups

Found in lots of extracellular proteins

Question 13

ionic bonds

Answer 13

between amino acid residues with oppositely charged R groups.

Question 14

quartenary structure

Answer 14

the spatial arrangement of individual polypeptide chains in a multi-subunit protein.

Question 15

denaturation

Answer 15

when the secondary and tertiary structure bonds are broken. it alters the shape and , hence the function of the protein

Question 16

causes of denaturation?( 6)

Answer 16

1-heat
2-solvents
3-acids
4-cross-linking reagents e.g. formaldehyde
5-disulphide-bond reducers
6-chaotrpic agents e.g. urea

Question 17

how to break the primary structure?

Answer 17

to break the primary structure the peptide bonds must be broken.
peptidases are used.
EXO peptidases- break off a single amino acid at one time.
ENDO peptidases- break off the aminoacid from the middle
CARBOXY peptidases- break off the peptide bond from the coo
AMINO peptidases- break off the peptide bond from the NH2

Question 18

what does denaturation cause?

Answer 18

1- decreases solubility
2-alters water-binding abilities
3-loss of biological activity
4-improves digestibility