Proteins 1&2

Question 1

Aliphatic amino acids

Answer 1

Alkane/organic

Question 2

Basic amino acid

Answer 2

Alkaline

Question 3

Aromatic amino acids

Answer 3

Benzene

Question 4

Other amino acid

Answer 4

Proline

Question 5

Peptide bond

Answer 5

Formation of covalent bond with loss of water

Question 6

Primary structure

Answer 6

Sequence of amino acids in polypeptide

Versatility in protein structure and function

Question 7

Secondary structure

Answer 7

Spatial arrangement of amino acid residues near each other in linear sequence

Question 8

Alpha helix

Answer 8

Held in place by hydrogen bonds

Question 9

Beta pleated sheets

Answer 9

Hydrogen bonds between amide groups of linear polypeptide chain - porin

Question 10

Tertiary structure

Answer 10

Spatial arrangement of amino acid residues that are far apart in a linear sequence

Question 11

Examples of tertiary structure

Answer 11

hydrophobic interactions
Disulphide bridges
Van der waals
Hydrogen bonds

Question 12

Ionic interactions

Answer 12

2 close oppositely charged R groups strong but rare

Question 13

Van der waals

Answer 13

Non specific weak

Stabilise structure as strong together

Question 14

Hydrogen bonds

Answer 14

Strong and permanent

1/20 strength of hydrogen bonds

Question 15

Hydrophobic interactions

Answer 15

Intra polypeptide

Question 16

Disulphide bridges

Answer 16

2 cysteine residues

Question 17

Quaternary structure

Answer 17

Spatial arrangement of individual polypeptide chains in a multi sub-unit protein
CRP - high when infected and haemoglobin

Question 18

Denaturation - causes

Answer 18

Acids, heats, solvents, cross link reagents, chaotropic agents - molecule in water which disrupts bonds, disulphide bond reducers

Question 19

What structures are effected by denaturation?

Answer 19

Secondary and tertiary

Question 20

What are the effects of denaturation

Answer 20

• decreased solubility
• loss of water binding capacity
• Loss of biological activity
• Improved digestibility

Question 21

Peptidases

Answer 21

Cleave peptide bonds

Question 22

Endopeptidase

Answer 22

Cleave internal bonds

Question 23

Exopeptidase

Answer 23

Cleave one amino acid at a time

Question 24

Carboxypeptidase

Answer 24

Cleave at COOH

Question 25

Aminopeptidase

Answer 25

Cleave at NH2

Question 26

What is protein structure dependent on?

Answer 26

DNA sequence

Question 27

Name 3 other types of proteins

Answer 27

- glycoprotein - Lipoproteins - metalloprotein

Question 28

Glycoprotein

Answer 28

Protein and carbohydrate post translational modification Sugar binds to amino acid

Question 29

Example of glycoprotein

Answer 29

Antibody

Question 30

Roles of glycoproteins

Answer 30

cell recognition and signalling Protein stabilisation solubility

Question 31

Lipoprotein example

Answer 31

LDL, HDL

Question 32

Roles of lipoprotein

Answer 32

Transport water insoluble fats around the body

Question 33

Metalloprotein

Answer 33

1/3 of proteins - metal ion needed for activity

Question 34

Functions of metalloprotein

Answer 34

Transport Enzyme Storage Signalling

Question 35

Globular proteins

Answer 35

Varied function including enzymes, hormones

Question 36

Fibrous proteins

Answer 36

Structural function eg tendon, connective tissue

Question 37

Membrane proteins

Answer 37

Cell/organelle proteins | Transporters and cell adhesion

Question 38

Co-operative binding

Answer 38

Binding at one subunit causes a change in shape of other subunits altering affinity for substrate

Question 39

Scurvy

Answer 39

Amino acid==>hydroxyamino acids Weaker collagen Acquired condition

Question 40

Osteogenesis imperfecta

Answer 40

Small glycine substituted for larger amino acid Not as tight coil, reduced fibril interaction Loss of secondary and tertiary structure Weak and brittle collagen

Question 41

What is the main part of LDL

Answer 41

ApoB

Question 42

What internalises LDL?

Answer 42

Glycoprotein

Question 43

Where is LDL broken down?

Answer 43

Lysosomes

Question 44

Classes of effects and mutations in receptor

Answer 44

- No receptor produced - Receptors never reach cell surface - Receptors cant bind LDL - Receptors don't internalise on binding LDL - Receptors do not release LDL

Question 45

FH

Answer 45

Autosomal dominant | Mutation in LDL receptor

Question 46

Cryoglobulin

Answer 46

Proteins that precipitate in blood and solidify below 37 degrees which is a problem in extremities on a cold day