1.2

Question 1

what bonds form the 3D structure of a protein

Answer 1

hydrogen bonds
disulfide bonds
ionic bonds

Question 2

how do hydrogen bonds form in proteins

Answer 2

negative oxygen in the carboxylic acid and positive hydrogen in amino acid group important in folding and coiling

Question 3

how do disulfide bonds form in proteins

Answer 3

two cysteine molecules close together
oxidation reaction creates covalent bond between two sulfur
stronger than hydrogen bond
needed to hold folding of amino acid chains

Question 4

how do ionic bonds form in proteins

Answer 4

strongly positive and negative amino acid side chains form ionic bonds also known as salt bridges

Question 5

explain the primary structure of protein

Answer 5

sequence of amino acids held by peptide bonds

Question 6

explain the secondary structure of a protein

Answer 6

the arrangement of the polypeptide chain into a regular repeating structure held by hydrogen bonds

Question 7

what is alpha helix structure

Answer 7

spiral coil
peptide bonds form backbone
R group stick out in all directions

Question 8

what is the beta pleated sheet structure

Answer 8

regular pleats held by hydrogen bonds most fibrous proteins have this structure

Question 9

explain the tertiary structure of proteins

Answer 9

level of 3D organization further folding into complex shapes held by hydrogen bonds, disulfide bonds, ionic bonds
e.g. globular proteins

Question 10

which structure are fibrous & globular proteins

Answer 10

fibrous - secondary
globular - tertiary

Question 11

explain the quaternary structure of a protein

Answer 11

3D arrangement of multiple tertiary poly-peptides and the addition of a prosthetic group
e.g. hemoglobin

Question 12

what is the structure of a fibrous protein and give an example

Answer 12

little/no tertiary structure long parallel peptide chains occasional cross-linkages form fibers insoluble
e.g. collagen

Question 13

state 5 uses of fibrous proteins

Answer 13

connective tissue in tendons
matrix of bones
structure of muscles
silk of spiderwebs
silk worn cocoons
keratin

Question 14

explain the structure of collagen and what it’s used for

Answer 14

strengths tendons, bones, ligaments & skin
3 poly peptide chains each about 1000 amino acids
triple helix held by hydrogen bonds, found together in fibrils

Question 15

what structure do globular proteins have

Answer 15

tertiary & sometimes quaternary

Question 16

why do globular proteins not dissolve in water

Answer 16

they are too big so instead form a colloid

Question 17

why are globular proteins important

Answer 17

hold molecules in position in the cytoplasm
forms enzymes & hormones

Question 18

what type of proteins are red blood cells

Answer 18

globular & conjugated

Question 19

what is a conjugated protein

Answer 19

a protein which is joined with a prosthetic group

Question 20

what prosthetic group does a red blood cell have

Answer 20

iron

Question 21

what are glycoproteins

Answer 21

proteins with a carbohydrate prosthetic group

Question 22

what are the properties of glycoproteins

Answer 22

they hold onto a lot of water so it is harder for them to be broken down
very slippery & viscous

Question 23

give an example of a glycoprotein

Answer 23

mucus
synovial fluid

Question 24

what are lipoproteins

Answer 24

proteins conjugated with lipids

Question 25

why are lipoproteins important

Answer 25

transport of cholesterol - lipid prosthetic group enables it to combined with the lipid cholesterol

Question 26

how big are LDLs (low density lipoproteins)

Answer 26

22nm

Question 27

how big are HDLs (high density proteins) and why do they have a higher density

Answer 27

8-11nm
contain more protein