Proteins

Question 1

Parts of central carbon (C) atom

Answer 1

Carboxyl group
– Amino group
– H atom
– Side chain (R), functional group

Question 2

the 8 essential amino acids

Answer 2

Leucine
Isoleucine
Valine
Threonine
Methionine
Phenylalanine
Tryptophan
Lysine

Question 3

What is transamination

Answer 3

transfer of amino groups = non-essential amino acid

Question 4

Primary protein structure

Answer 4

sequence of AA (no other bonds)

Question 5

Secondary protein structure

Answer 5

local folding to helices
- stabilised by (non-covalent) hydrogen bonds
- carboxyl (C=O) and amide (N-H) groups

Question 6

Tertiary protein structure

Answer 6

overall shape (3D folding)

Question 7

Quaternary protein strutcure

Answer 7

arrangement of multiple polypeptides (sub-unit association)

Question 8

Protein denaturation

Answer 8

An irreversible process in which the structure of protein is disrupted
= partial/complete loss of function
* Caused by:
o Heat
o pH
o Mechanical actions (e.g. beating or whipping)
o Alcohol/salts
* Can result in coagulation (clotting or
curdling => insoluble protein mass)

Question 9

What are albumins

Answer 9

Protein
dissolves in water
fibrous - elongated, rope like

Question 10

What are globulins

Answer 10

protein
dissolve in dilute salt
spherical

Question 11

1g N = ? protein

Answer 11

1g N = 6.25g protein

protein 16% nitrogen

Question 12

Texture function of proteins

Answer 12

Gelling, foaming, coagualtion, emulsifying

Question 13

Colour function of proteins

Answer 13

Myoglobin, maillard reaction, enzymatic browning

Question 14

Flavour function of protein in foods

Answer 14

Sweetness, bitterness