pack 1 - Proteins

Question 1

what 4 groups does a protein always contain

Answer 1

carboxyl group
amine group
R group (residual)
hydrogen

Question 2

what reaction forms a dipeptide

Answer 2

condensation reactions

Question 3

what bonds form

Answer 3

peptide bonds

Question 4

where do the bonds from

Answer 4

between the amine group of one amino acid and the carboxyl group of another amino acid.

Question 5

what reactions breaks peptide bonds

Answer 5

hydrolysis

Question 6

describe the primary structure

Answer 6

specific sequence of amino acids in a polypeptide chain is formed by peptide bonds in a condensation reaction

Question 7

describe the secondary structure

Answer 7

bonds from between amine and carboxyl group
form an alpha helix or beta pleated sheet

Question 8

describe the tertiary structure

Answer 8

fold into a specific 3D shape which allows it to carry out its specific functions. held together by R groups

Question 9

describe the quaternary structure

Answer 9

3D containing more than one polypeptide chain

Question 10

what bonds from in tertiary and quaternary structure

Answer 10

hydrogen
ionic
disulphide

Question 11

what bonds from in the secondary structure

Answer 11

hydrogen

Question 12

structure of a fibrous protein

Answer 12

long and linear
little/no tertiary structure
hydrophobic R groups on outside- insoluble

Question 13

structure of a globular protein

Answer 13

fold into a spherical shape
have tertiary structure (some quat)
hydrophilic R groups on outside- soluble

Question 14

examples of fibrous proteins

Answer 14

fibrin
collagen
keratin

Question 15

examaples of globular proteins

Answer 15

enzymes
thrombin
fibrinogen
haemoglobin

Question 16

Fibrous protein riole

Answer 16

structural role in organisms

Question 17

globular proteins role

Answer 17

role in metabolic reactions

Question 18

how many polypeptide chains in haemoglobin

Answer 18

4

Question 19

function of haemoglobin

Answer 19

bind to oxygen to be carried around the blood

Question 20

how structure helps function of haemoglobin

Answer 20

• globular spherical structure = allows more haemoglobin to fit in each red blood cell
• form a conjugated protein = allow haem group to be held in correct position to bind to oxygen
• hydrophilic R group on outside = soluble to dissolve in cytoplasm of red blood cells

Question 21

structure of haemoglobin

Answer 21

compact sphere- globular protein
tertiary structure- ionic hydrogen and disulphide bonds
hydrophilic chains on outside
conjugated protein- each polypeptide is associated with a iron haem group

Question 22

collagen structure

Answer 22

fibrous protein
3 polypeptide chains wrap around each other- hydrogen and disulphide bonds-triple helix
staggered- collagen fibril- prevent weak points
cross links between molecules

Question 23

how collagen structure aids function

Answer 23

hydrophobic R groups on outside- insoluble so in BV blood cannot diffuse out
triple helix- give strength
staggered in a fibril- high strength and flexibility without stretching. required in skin, bones. artery walls

Question 24

what is a conjugated protein

Answer 24

proteins with another non protein group
(prosthetic) associated with their polypeptide chains