PROTEIN

Question 1

What elements are protein made up of

Answer 1

carbon hydrogen oxygen nitrogen

Question 2

what is the chemical structure of proteins

Answer 2

proteins are large molecules composed of amino acids

Question 3

basic structure of amino acids

Answer 3

NH2 to the left carbon in the middle H to the top R down below and cooh to the right

Question 4

what is essential amino acids

Answer 4

cannot be manufactored by the therefore need to be obtained by food
example is lysine and leucine

Question 5

what is non essential amino acid

Answer 5

can be manufactored by the body therefore dont need to be obtained by food
examples glycine proline

Question 6

how is a peptide bond formed

Answer 6

a peptide bond is formed when two amino acids join together. the cooh loses a oh and the nh2 loses a h the oh and h join togther and make up a H20 molecule which is water that is then loss. this is called a codensation reaction

Question 7

what is the strcuture of proteins

Answer 7

primary structure, secondary structure, tertiary structure

Question 8

what is primary structure

Answer 8

involves the order or sequence of amino acids in protein chains

Question 9

what is secondary structure

Answer 9

secondary structure involves the folding of primary structure of proteins into defiinite shapes.

Question 10

what are the two types of crosslinks

Answer 10

disulfide bonds and hydrogen bonds

Question 11

what is a disulfide bond

Answer 11

occurs when 2 sulfur of two amino acids join together to form either a single polypeptide chain or two different polypeptide chains

Question 12

what is a disulfide bond

Answer 12

occurs when 2 sulfur of two amino acids join together to form either a single polypeptide chain or two different polypeptide chains

Question 13

what is a disulfide bond

Answer 13

occurs when a hydrogen from the nh group of one amino acid and an oxygen from the c=o group of another amin acid join together to form either a single polypeptide chain or two different polypeptide chains

Question 14

what is a tertiary structure

Answer 14

involes the folding of the secondary structure of proteins into three dimensional shapes.

Question 15

what is denaturation

Answer 15

change in nature of a protein shape. unfolding of a
protein chain. resuting in an irreversible change in shape.
can be caused by heat enzymes, mechanical action. whipping and beating

Question 16

what are the causes of denaturation

Answer 16

heat, enzymes,mechanical action

Question 17

heat

Answer 17

causes protein chain to unfold and bond together. causing food to coagulate and set.

Question 18

enzymes

Answer 18

cause a change to the nature of proteins structure

Question 19

elasticity

Answer 19

some fibrous proteins, eg gluten in wheat, are quite elastic

Question 20

culinary application of elasticity

Answer 20

gluten makaes yeast dough elastic enough to trap the CO2 gas produced bby yeast, helping it rise

Question 21

heat culinary application

Answer 21

eggs white coagulate and change from translucent to opaque at 60 degress celcius and egg yolks coagulate at 68 degrees celcius

Question 22

maillard reaction

Answer 22

the non enzymic browning of foods due to certain amino acids and sugars under dry heat. it produces an attractive brown colour and a crust with an appetising flavour

Question 23

maillard reaction culinary appliacation

Answer 23

roast potatoes and roast meat

Question 24

solubility

Answer 24

most proteins are insoluble in water. apart from collagn in meat.
and egg albumin

Question 25

culinary application of solubility

Answer 25

mosit heat tenderisises meat by converting collagen to gelantine

Question 26

Gel formation

Answer 26

gelatine can absorb large amounts of water when heated as protein chains uncoil and water becomes trapped.
this froms a solution
on cooling a solution forms a gel, a semi solid viscous solution that has a 3 dimensional protein matrix

Question 27

gel formation culinary application

Answer 27

cheesecakaes, jelly sweets

Question 28

foam formation

Answer 28

when an egg white is whisked, protein chains unfold and air bubbles form.
protein chain entrap air creating a foam
whisking also creates heat that begins to set the egg albumin (known as temporary foam)
foam will collapse after a while unless subjected with heat