Proteins

Question 1

Biological roles of proteins include

Answer 1

Structure- collagen, keratin
Transport- membrane transport

Question 2

What determines amino acid properties

Answer 2

Side chain R

Question 3

What is the smallest amino acid to larger

Answer 3

Glycine, alanine, valine, leucine

Question 4

Why are amino acid hydrophobic

Answer 4

CH3 doesn’t interact with water

Question 5

Phenylanine is

Answer 5

Hydrophobic

Question 6

Hydrophilic and charged amino acids

Answer 6

Aspartame
Glutamate
Asparagine
Glutamine
Serine

Question 7

Cysteine can be used for

Answer 7

Disulfide bonds

Question 8

Transmembrane proteins function

Answer 8

Move materials through bilayer

Question 9

Special features of amino acids

Answer 9

Methionine- 1st amino acid in protein sequence determined by DNA start codin- ATG
Cytosine- disulphide bond formation

Question 10

Amino acid modification is

Answer 10

Serine and threonine- due to hydroxyl group
O linked glycosylation
Reversible phosphorylation
Asparagine- N linked glycosylation
Proline- ring- forces bend in protein structure

Question 11

Name of reaction of peptide bond formation

Answer 11

Condensation reaction

Question 12

Can free rotation occur in peptide bond formation

Answer 12

Yeah

Question 13

Amino acid sequence determines

Answer 13

Protein structure

Question 14

IY structure is the only interaction between amino acids and

Answer 14

Peptide bond

Question 15

What is secondary structure

Answer 15

Local structure of polypeptide chain
Bonding is due to hydrogen bonding- way protein starts to fold

Question 16

Can secondary structure be easily broken

Answer 16

Alpha helix
Beta sheet

Question 17

Alpha helix structure features

Answer 17

Rod like structure
Coiled peptide chain
R groups extend outwards from axis
H bonding between CO and NH4 residues away

Question 18

Alpha helix is intertwined with

Answer 18

Myosin
Tropomyosin
Muscle fibrin in blood clots
Keratin in hair

Question 19

Beta sheet features

Answer 19

Polypeptide chain is extended
H bonding between CO and NH on different polypeptide strands
Strands run parallel or anti parallel
Anti parallel strands connected by B turns
Silk strong structure

Question 20

What is tertiary structure

Answer 20

Side chain R group interactions
Most are weak, non covalent interactions but stabilise and fold proteins- globular proteins

Question 21

Many globular proteins are

Answer 21

Carriers- enzymes and receptors

Question 22

Types of tertiary structure bonding

Answer 22

H bonding
Electrostatic interactions between charged groups
Hydrophobic interactions
Van der waals forces
Disulphide bonds- between cysteine residues

Question 23

Quaternary structure is

Answer 23

Complex of 2 or more separate polypeptide chains.
Interaction between subunits
Non covalent and covalent interactions
Allosteric properties- can change shape
Haemoglobin
4 subunits interacting

Question 24

What does protein denaturation do

Answer 24

Disrupts bonding

Question 25

Heat breaks what type of bonding

Answer 25

Weak

Question 26

PH affects

Answer 26

Bonding Electrostatic interactions

Question 27

Chaotropic agents

Answer 27

Form H binds with amino acids and disrupt existing H bonds and hydrophobic interactions

Question 28

Is denaturation of tertiary structure reversible

Answer 28

Yes

Question 29

Protein folding involves what type of protein

Answer 29

Chaperone

Question 30

Gene mutation causes

Answer 30

Change in AA sequence

Question 31

Substitutions can cause a

Answer 31

Conservative- same type of AA Radical- different type of AA

Question 32

Substitutions alter

Answer 32

Ligand binding or enzyme activity Affect shape of proteins

Question 33

Insertions and deletions can

Answer 33

Cause loss of protein function Deletions can determine binding site residues

Question 34

X-ray crystallography

Answer 34

Complete 3D structure

Question 35

Collagen triple helix

Answer 35

3 amino acids per turn

Question 36

Scurvy is

Answer 36

Vitamin C deficiency

Question 37

Prior diseases is

Answer 37

Fibrous forms of protein aggregate

Question 38

Scrapie susceptibility is

Answer 38

Already formed fibrils act as template

Question 39

ARR type 1 is resistant to

Answer 39

Scrapie

Question 40

VRQ type is susceptible to

Answer 40

Sheep

Question 41

Why does the scrapie form not propagate well

Answer 41

It’s resistant

Question 42

Proteomics is

Answer 42

Study protein profile of cell or tissue

Question 43

Qualitative is

Answer 43

Difference in amino acid sequence

Question 44

Quantitative is

Answer 44

Increase or decrease in proteins

Question 45

Non biased approach

Answer 45

Looks at all proteins

Question 46

Proteins are separated based on their

Answer 46

Size Charge

Question 47

How are proteins separated

Answer 47

Isoelectric focusing 1st step- proteins move in pH gradient and when they reach isoelectric point they may stop 2nd step- SDS page

Question 48

Advantages of 2D structure

Answer 48

Very good resolution Separate complex protein mixtures