Protein

Question 1

Element

Answer 1

Carbon
Oxygen
Hydrogen
Nitrogen

Question 2

Basic structure amino acid

Answer 2

Labelled

Question 3

Formation of peptide link

Answer 3

Oxygen and hydrogen from first amino acid in the carboxyl group joins with the first hydrogen in the amino group in their second amino acid which forms water
The end of carbon and oxygen in the first amino acid in the carboxyl group joins with nitrogen and a seven hydrogen in the amino group and the second amino acid which forms the peptide link and the process is called condensation process

Question 4

Essential amino acid

Answer 4

Cannot be made in the body and must be obtained from food

Example histidine, argarinine

Question 5

Non-essential amino acid

Answer 5

Made in the body and not essential to go from food

Example proline

Question 6

Three structures of protein

Answer 6

1. primary structure
2. secondary structure
3. territory structure

Question 7

Primary structure

Answer 7

Order a number of amino acid in the protein chain

Question 8

Secondary structure

Answer 8

Coiling of primary structure giving spiral shape
Held in place by either=
1. disulphide bond 
Or 
2. hydrogen bond

Question 9

Tertiary structure

Answer 9

Folding of the secondary structure
A) fibrous eg gluten base difficult to tear
Or
B) globular eg albumin in egg white

Question 10

Classification of proteins

Answer 10

1. simple proteins

2. conjugated proteins

Question 11

Simple proteins

Answer 11

Animal - fibrous e.g. collagen in meat
- globular e.g. albumin in egg white
Plant - glutenins e.g. gluteninin in wheat is soluble in acid and alkaline
- prolamins e.g. zein in maze is soluble in alcohol

Question 12

Conjugated proteins

Answer 12

• Protein combines with non-protein molecule
• e.g. lipoprotein e.g. lechtin in egg yolk
• e.g. phosphoprotein e.g. caesinogen in milk

Question 13

High biological value protein

Answer 13

Contains all the essential amino acid in the correct proportion needed by the body
e.g. eggs milk cheese meat

Question 14

low biological value protein

Answer 14

Does not contain all essential amino acids in the correct proportion a divided body
e.g. wheat maize rice

Question 15

Complimentary/ supplementary value protein

Answer 15

Two low biological value protein foods combined together so all essential amino acids are in the correct proportion a divided body
e.g. beans (lysin) on toast (methionine)

Question 16

Properties/characteristics

Answer 16

Denaturation
 Mailard reaction 
solubility 
elasticity 
Gel formation
Foam formation

Question 17

Denaturation

Answer 17

Invertible change in protein structure 
Caused by 
heat eg fried eggs
chemicals eg lemon juice curdle milk
agitation eg whipping eggs white foam
enzymes eg renin causes casein in milk form curd cheese

Question 18

Mailard reaction

Answer 18

Amino acid+sugar+dry heat= browning

Eg toast

Question 19

Solubility

Answer 19

Insoluble in water accept albumin in egg white

Question 20

Elasticity

Answer 20

Fibrous protein elastic

e.g. gluten and bread

Question 21

Gel formation

Answer 21

Collagen heated from gelatine setting agent used in cheesecakes jelly and sweet
can absorb large amount of water when heated

Question 22

Foam formation

Answer 22

Egg white whisked
form temporary foam trapping air
Oven sets as permanent foam

Question 23

Digestion

Answer 23

Stomach- gastric juice - rennin/ Pepsin
pancreas- pancreatic juice - trypsin
small intestine- intestinal juice - peptidase

Question 24

Dry and moist heat effect on protein

Answer 24

• coagulation eg egg white coagulate at 60’C and yolk at 68’C
• colour change (myoglobin (red pigment) to haematin(brown pigment)
• overcooking (indigestible)

Question 25

Dry heat affect on protein

Answer 25

Mailard reaction eg roast beef

Question 26

Moist heat effect on protein

Answer 26

Tenderising meat= collagen in meat coverts to gelatine causing fibres to tenderise eg pulled pork

Question 27

Stomach

Answer 27

Gastric juice
= rennin - caesogin - casein
= pepsin - protein - peptones

Question 28

Pancreas

Answer 28

Pancreatic juice

= trypsin- peptones - peptides

Question 29

Small intestine

Answer 29

Intestinal juice

= peptidase - peptides - amino acids

Question 30

Deamination

Answer 30

Excess amino acids broken down by the body in the liver
=NH2 - ammonia + urea = excreted as urine through kidneys
=COOH - oxidised for heat and energy