protein

Question 1

explain foam formation

Answer 1

when an egg white is whisked, protein. chains unfold and air bubbles form, the protein chains entraps air, creating a foam

Question 2

give on culinary example of foam formation

Answer 2

meringues

Question 3

state two cause if protein denaturation and give one example in each class

Answer 3

heat - hard boiled eggs
mechanical action - sponge cake

Question 4

give a detailed account of protein and refer to - how a peptide bond is formed (1)

Answer 4

the COOH (acidic) group of one amino acid reacts with the NH2(basic) group of another

           H.      O
				     I         II
NH2 - 	C   -    C  - OH
			      	I
		         R

H.   H
	I.    I
	N - C - COOH
	I.     I
	H.    R

Question 5

give a detailed account of protein and refer to - how a peptide bond is formed (2)

Answer 5

the COOH group loses an OH group. the NH2 group loses a hydrogen atom . the hydrogen atom and the OH group join together to form a water molecule that is lost

Question 6

give a detailed account of protein and refer to - essential amino acids

Answer 6

cannot be mauncafacured by the bit, therefore, must be obtained form food. there are 10 essential amino acids, adults rewire 8 of these and children require 10

Question 7

give a detailed account of protein and refer to - non essential amino acids

Answer 7

can be manufactured by the body, therefore, do not need to be stained from food. there are 10 non essential amino acids

Question 8

give a detailed account of protein and refer to - supplementary value

Answer 8

low biological value (LBV) proteins are deificnet in one or more essential amino acids. consuming two LBV protein together(each lacking different essential amino acids ) can ensure all essential amino acids are obtained . an example of this is beans and toast

Question 9

explain gel formation

Answer 9

the collagen is heated it is converted to gelatine. gelatine can absorb large amounts of water when heated, as protein chains until and water becomes trapped. this forms a sol.on cooling, a sol forma a gel, a semi solid viscous solution that has 3D protein matrix in which water molecules become trapped e.g. cheesecake, jelly

Question 10

example of essential amino acid

Answer 10

valine
lysine

Question 11

example of non essential amino acid

Answer 11

proline
glycine

Question 12

name one food source of each of the proteins - casein, actin, albumin

Answer 12

casein - milk
actin - meat
albumin - eggs

Question 13

explain protein deamination

Answer 13

the process through which excess amino acids are broken down by the body in the liver

Question 14

give a detailed account of protein and refer to - classification (simple, animal)

Answer 14

fibrous - elastin,collagen - meat connective tissue, meat connective tissue
globular - ovalbumin, lactalbumin - egg white, milk

Question 15

give a detailed account of protein and refer to - classification (simple, plant)

Answer 15

gluetenins - gluetenin, orzenin - wheat, rice
protamines - gliadin,zein - wheat, maize

Question 16

give a detailed account of protein and refer to - classification (conjugated)

Answer 16

lipoproteins - lecithin - eggs
phosphoproteins - caseinogen - milk

Question 17

give a detailed account of protein and refer to - structure(primary)

Answer 17

-this is the order sequence of amino acids in protein chains
-amino acids are linked together by peptide links

Question 18

give a detailed account of protein and refer to - structure - secondary

Answer 18

-this involves the folding of the primary structure of proteins into definite shape
-disulfie bonds - occur when two sulfrs from two amino acids join together
-hydrogen bonds - occur when a hydrogen from one chain and an oxygen from another chain join together

Question 19

give a detailed account of protein and refer to - structure - tertiary

Answer 19

-this involves th folding od the secondary structure of proteins into 3D shapes
-further cross linking between amino acids forms definite shapes, which may be fibrous or globular

Question 20

function of structural proteins

Answer 20

growth and repair of body cells

Question 21

function of physiologically active proteins

Answer 21

production of hormones, enzymes, antibodies

Question 22

function of nutrient protein

Answer 22

provides essential amino acids for the body