unit 2 KA5 - proteins

Question 1

what are proteins uses in the body

Answer 1

• they are the major structural materials of animal tissue
• involved in the maintenance and regulation of life processes
• enzymes are proteins which act as biological catalysts
• hormones such as insulin which is used for blood sugar regulation are made from protein

Question 2

what are amino acids

Answer 2

amino acids are the building blocks from which proteins are formed, and are relatively small molecules which all contain an amino group -NH2, and a carboxyl group -COOH

Question 3

how are proteins made

Answer 3

they are made of many amino acid molecules linked together by condensation reactions. in these reactions, the amino group of one amino acid and the carboxyl group of another amino acid join, with the elimination (production) of water

Question 4

what is the link that forms between two amino acids known as

Answer 4

the peptide or amino link. looks like -CONH-

Question 5

is it true that proteins which fulfil different roles in the body are formed by linking together differing sequences of amino acids

Answer 5

ye

Question 6

what is meant by essential amino acids

Answer 6

the body cannot make all of the amino acids which are required for protein synthesis, so certain amino acids known as essential amino acids must be acquired from the diet

Question 7

what is meant by essential amino acids

Answer 7

the body cannot make all of the amino acids which are required for protein synthesis, so certain amino acids known as essential amino acids must be acquired from the diet

Question 8

what produces amino acids during digestion

Answer 8

enzyme hydrolysis of protein

Question 9

is it true that the structural formula of amino acids obtained from the hydrolysis of a protein can be drawn given the structure of a section of the protein?

Answer 9

yes

Question 10

how can the structural formula of a section of protein be drawn

Answer 10

from the structural formulae of the amino acids from which it is formed

Question 11

what can the long chain molecules within proteins form

Answer 11

spirals, sheets or other complex shapes

Question 12

how are the long chain molecules within proteins held together

Answer 12

by intermolecular bonding between the side chains of the constituent amino acids.

Question 13

how are proteins denatured

Answer 13

when they are heated, the intermolecular bonds are broken, allowing the proteins to change shape ie denature

Question 14

what does it mean to denature

Answer 14

to change shape

Question 15

why does the texture of food change when it is cooked

Answer 15

because of the denaturing of the proteins in the food that occurs due to the heat