proteins

Question 1

proteins

Answer 1

made of amino acid monomers
-conatain an amino group (NH2), carboxylic acid group (-COOH), variable R group (C containing chain)

Question 2

how many amino acids are there

Answer 2

20
each determined by their dif. R groups

Question 3

how are amino acids joined

Answer 3

peptide bonds formed in condensation reactions

Question 4

dipeptide

Answer 4

2 amino acids

Question 5

polypeptide

Answer 5

3 or more amino acids

Question 6

primary structure

Answer 6

• order and no. of amino acids in a protein
• contains the initial sequence of amino acids
• will therefore determine the proteins function in the end

Question 7

secondary structure

Answer 7

-shape that the chain of amino acids chains (alpha helix or beta pleated)
-H in the -NH has a slight +ve charge
-O in the =CO has a slight -ve charge
-so weak H2 bonds can form leading to alpha helices or beta pleated sheets

Question 8

tertiary structure

Answer 8

-3D shape of proteins formed from further twisting and folding
-a no. of dif. bonds maintain the structure:
1)disulphide bridges= interactions between the sulfur in the R group of the amino acid cystesine (strong and not easily broken)
2)ionic bonds= between carboxyl + amino groups that aren’t involved in the peptide bond (easily broken by pH and weaker than disulphide bridges)
3)H2 bonds= numerous + easily broken

Question 9

proteins can be either

Answer 9

globular or fibrous

Question 10

globular proteins

Answer 10

e.g. enzymes
compact

Question 11

fibrous proteins

Answer 11

e.g. keratin
long + can be used to form fibres