Protein structure

Question 1

proteins

Answer 1

polymers made of monomers called amino acids

Question 2

monomers of polypeptides

Answer 2

monomers

Question 3

how many amino acids are there

Answer 3

20

Question 4

structure of amino acid

Answer 4

Central carbon atom bonded to:
- Amine
- carboxylic group
- hydrogen atom
- R group

Question 5

bonds formed between amino acids

Answer 5

peptide bonds

Question 6

peptide bonds

Answer 6

• covalent bonds

Question 7

how do peptide bonds form

Answer 7

An -OH is lost from the carboxylic group of one amino acid and an H atom is lost from the amine group of another via condensation reaction

Question 8

dipeptides

Answer 8

formed by the condensation of two amino acids

Question 9

polypeptides

Answer 9

formed by the condensation of many amino acids

Question 10

what happens during a hydrolysis reaction

Answer 10

peptide bond breaks with the addition of water, breaking it down to amino acids

Question 11

primary structure

Answer 11

• sequence of amino acids in a polypeptide chain
• bonding: peptide bond
• determins proteins overall shape and function

Question 12

secondary structure

Answer 12

• folding or coiling of the polypeptide chain into a- helixs or beta pleated sheets
• hydrogen bonds between -C=O group of one amino acid and the amine group of another

Question 13

what does secondary structure forms

Answer 13

a-helix: coiled structure stabalized by hydrogen bonds
B- pleated: Zig zag pattern forming sheat-like structures

Question 14

tertiary structure- definition

Answer 14

three-dimensional folding of a polypeptide, giving the protein its functional shape

Question 15

tertiary structure bonding

Answer 15

1. H bonds: weak between polar groups
2. ionic bonds: oppositely charged R- groups
3. Disulfide bonds: covalent between sulfur attoms
4. Hydrophobic interactions: Nonpolar R groups clustering away from water

Question 16

quaternary structure definition

Answer 16

arrangement of 2 or more polypeptide chains into functional protein

Question 17

examples of quaternary structures

Answer 17

haemoglobin
collagen

Question 18

haemoglobin

Answer 18

water-soluble globular protein

Question 19

collagen

Answer 19

fibrous protein consisting of 3 polypeptide chains wound around each other

Question 20

globular proteins

Answer 20

compact
roughly spherical

Question 21

why do globular proteins form spherical shape when folding into their tertiary structure

Answer 21

• non polar R groups are oriented towards the centre of the protein, away from aqueous surroundings
• polar hydrophillic R groups oriente themselves towards the outside

Question 22

globular proteins functions

Answer 22

physiological roles as they are easily transported around and are involved in metabolic reactions

Question 23

haemoglobin structure

Answer 23

1. polypeptide chains
   - two alpha chains
   - two beta chains
2. haem group
   - 4 haem groups, that contain Fe2+ that binds to oxygen

Question 24

collagen structure

Answer 24

• 3 polypeptide chains closely held together by hydrogen bonds to form a triple helix
• each of the 3 chains are coils
• hydrogen bonds form between the coils
• covalent bonds form cross-links between R groups of amino acids, in interacting triple helices

Question 25

collagen function

Answer 25

- form structure of bones - makes up cartilage and connective tissue - prevents blood from bursting walls of arteries - the main component of tendons