Proteins

Question 1

Which of the following groups on an amino acid determines its chemical properties:
hydrogen
a-amino
a-carboxyl
R group

Answer 1

R group

Question 2

Other than:
shape
size
polarity
sulphur-containing
imino
Name another way to categorise R groups?

Answer 2

Charge

Question 3

What are the 9 non-polar amino acids?

Answer 3

Glycine
Alanine
Valine
Leucine
Isoleucine
Methionine
Phenylalanine
Tryptophan
Proline

Question 4

What are the polar amino acids?

Answer 4

Serine
Threonine
Cysteine
Tyrosine
Asparganine
Glutamine

Question 5

Name the acidic amino acids.

These are negatively charged.

Answer 5

AspartATE

GlutamATE

Question 6

Name the basic amino acids.

These are positively charged.

Answer 6

Histidine
Arginine
Lysine
(HAL)

Question 7

Which amino acid is not optically active?

Answer 7

Glycine

Question 8

Which type of amino acids are found in proteins:
B isomers
L isomers
D isomers
P isomers

Answer 8

L isomers

Question 9

What stage of protein sturcture is B pleated sheets?

Answer 9

Secondary

Question 10

What bonds join amino acids?

Where does this occur?

Answer 10

Peptide

Ribosomes

Question 11

Do amino acids get added from C-terminus to N-terminus or N-terminus to C-terminus?

Answer 11

N –> C

Question 12

Peptide bonds have partial double bond characteristics.

True or false?

Answer 12

True

Question 13

What are the 2 types of secondary protein structures?

Answer 13

a-helices

B-pleated sheets

Question 14

In a-helices where are the intrachain H bonds?

What is the function of these bonds?

Answer 14

Between N-H and C=O

Stabilise helix

Question 15

Which residue does residue 1 join to in an alpha helix?

Answer 15

5

Question 16

Which residue does residue 7 get joined by in an alpha helix?

Answer 16

3

Question 17

Which residue does residue 2 join to in an alpha helix?

Answer 17

6

Question 18

In terms of H bonding between adjacent strands in B-pleated sheets, what are:

1) Interchain H bonds
2) Intrachain H bonds

Answer 18

1) Between different amino acid chains

2) Between 2 parts of same amino acid chain

Question 19

Where does the R group lie in relation to the B-pleated sheet?

Answer 19

Outside plane of sheet

Question 20

What type of amino acids lie in the interior of proteins?

Give examples.

Answer 20

Hydrophobic
Leucine
Vlaine
Methionine
Phenylalanine

Question 21

What type of amino acids lie in the exterior of proteins?

Give examples.

Answer 21

Hydrophillic
Arginine
Histidine
Lysine
Asparatate
Glutamate

Question 22

Between which type of amino acids do salt bridges exist?

Answer 22

Oppositely charged

Question 23

Between which amino acids do disulphide bonds exist?

Answer 23

Cysteine

Question 24

VdW forces exist between..?

Answer 24

Neutral molecules

Question 25

Which precursor protein is responsible for Alzheimer's disease?

Answer 25

Amyloid precurson protein

Question 26

Which protein is found in the brain that is responsible for Alzheimer's disease?

Answer 26

Amyloid B protein

Question 27

What are the roles of plaques formed from the amyloid B protein fibrils in Alzheimer's disease?

Answer 27

Destroy neurons

Question 28

Which protein is responsible for Creutzfeldt Jacob Disease (CJD)?

Answer 28

Prion protein (PrPSc)

Question 29

Which type of proteins are elongated and insoluble?

Answer 29

Fibrous

Question 30

Which type of proteins are soluble and compact?

Answer 30

Globular

Question 31

What type of proteins are ion channels?

Answer 31

Membrane

Question 32

Being a carrier of which two diseases provides resisatnce to malaria? How?

Answer 32

Thalassaemia - smaller RBCs with less haemoglobin so parasite cannot penetrate Sickle cell anaemia - RBCs sickle in response to parasite so it gets trapped

Question 33

What is myoglobin?

Answer 33

An oxygen store

Question 34

Does myoglobin have a primary, secondary, tertiary or quaternary structure?

Answer 34

Tertiary

Question 35

How many alpha helices does myoglobin have?

Answer 35

8

Question 36

What are the differences between haemoglobin and myoglobin in: 1) Oxygen binding 2) Oxygen affinity

Answer 36

1) Haem = cooperative Myo = non-cooperative 2) Haem = pH/CO2 dependent and regulated by BPG Myo = not pH/CO2 dependent nor regulated by BPG

Question 37

What does allosteric mean?

Answer 37

Binding of oxygen to one subunit affects interactions with other subunits

Question 38

What substitution takes place when oxygen binds to haemoglobin? How does this affect affinity?

Answer 38

His F8 --> His E7 | Increases affinity of haem subunits for oxygen

Question 39

Does the T state or R state have a higher affinity?

Answer 39

R state

Question 40

Where does BPG bind in T state?

Answer 40

Between beta subunits

Question 41

At high altitudes what happens to BPG? | What is the result of this on Hb affinity for O2?

Answer 41

BPG increases | Reduced affinity

Question 42

How effectively can BPG bind to foetal Hb and why?

Answer 42

Less effectively | Prevents reduction in affinity

Question 43

What are the 4 invariant amino acids?

Answer 43

His F8 His E7 Gly B6 Pro C2

Question 44

What is the difference between conservative and non-conservative substitution?

Answer 44

``` Conservative = maintains hydrophobic interior Non-conservative = has major affect on protein structure/function ```

Question 45

Which collagen types are fibril-forming?

Answer 45

Types 1, 2, 3

Question 46

Which collagen types are network-forming?

Answer 46

Types 4, 7

Question 47

Which collagen types are fibril-associated?

Answer 47

Types 5, 9, 12

Question 48

Which collagen type forms all basal lamina?

Answer 48

Type 4

Question 49

Which collagen type forms cartilage?

Answer 49

Type 2

Question 50

Which hydroamino acid is an attachment site for sugars and involved in crosslinking collagen chains?

Answer 50

Hydrolysine

Question 51

Which hydroxyamino acid is responsible for stabilising the triple helix and involved in H bond formation?

Answer 51

Hydroxyproline

Question 52

What is the cofactor needed for prolyl hydroxylase and lysyl hydroxylase to work?

Answer 52

Ascorbic acid (Vit D)

Question 53

What disease results from excess collagen production?

Answer 53

Dupuytren's contracture

Question 54

Osteogenesis imperfecta is caused by what?

Answer 54

Mutation in collagen chains

Question 55

What disease results from a deficiency of lysyl oxidase?

Answer 55

Ehers-Danlos syndrome type VI

Question 56

What causes scurvy?

Answer 56

Vit D deficiency

Question 57

Which amino acids contain sulphur?

Answer 57

Cysteine | Methionine

Question 58

Name an imino acid

Answer 58

Proline

Question 59

Which amino acid is an a-helix terminator?

Answer 59

Proline

Question 60

Which amino acids are aromatic?

Answer 60

Phenylalanine Tyrosine Tryptophan

Question 61

What is the 21st amino acid?

Answer 61

Selenocysteine

Question 62

Name a large amino acid.

Answer 62

Tryptophan