Biochem

Question 1

Heat shock proteins as chaperones

Answer 1

• Prevent aggregation of unfolded chain
• Assist achieving proper protein conformation
• Help transport partially folded proteins across membranes

Question 2

Mislocalisation

Answer 2

process by which misfolded protein isn’t transported to its original location

Question 3

formation of disulphide bonds between amino acids

Answer 3

Oxidation between cysteine residues

Question 4

Which amino acid contains only 1 amino group?

Answer 4

Proline

Question 5

TRUE/FALSE

Disulphide bonds are more common in intracellular proteins

Answer 5

FALSE

more common in extracellular, as they are less protected so need better support

Question 6

Can peptide bonds rotate?

Answer 6

No - as they have double bond character due to resonance of e- between C and N

Question 7

direction of residues in an alpha helix

Answer 7

hydrophobic residues point inward.

hydrophillic residues point outward.

Question 8

β strands

Answer 8

polypeptide chains that are almost fully extended

Question 9

β sheets

Answer 9

multiple β strands arranged side-side, stabilised by H bonds between C=O and N-H on adjacent strands

Question 10

parallel β sheets

Answer 10

strands run in the same N- to C- terminal direction

Question 11

antiparallel β sheets

Answer 11

strands run in opposite N- to C- terminal directions

Question 12

screw sense

Answer 12

The direction in which a helical structure rotates with respect to its axis

Question 13

native conformation

Answer 13

Polypeptide chain folds into a single stable shape, determined by sequence of amino acids & other important factors. Determines biological function

Question 14

Helix-loop-helix

Answer 14

two helices connected by a turn

Question 15

Coiled-coil

Answer 15

Two amphipathic α helices that interact in parallel through their hydrophobic edges

Question 16

Helix bundle

Answer 16

Several α helices that associate in an antiparallel manner to form a bundle

Question 17

β α β Unit

Answer 17

Two parallel β strands linked to an intervening α helix by two loops

Question 18

Hairpin

Answer 18

Two adjacent antiparallel β strands connected by a β turn

Question 19

β Meander

Answer 19

Antiparallel sheet composed of sequential β strands connected by loops or turns

Question 20

Greek key

Answer 20

4 antiparallel strands (strands 1,2 in the middle, 3 and 4 on the outer edges)

Question 21

β Sandwich

Answer 21

Stacked β strands or sheets

Question 22

domain

Answer 22

Independently 3D folded, compact units in proteins

Question 23

Proteins with very specific binding identities or catalytic functions are likely to possess

Answer 23

protein domains

Question 24

All β

Answer 24

Only β sheets & connecting loop structures

Question 25

α + β

Answer 25

Local clusters of α helices & β sheet in separate, clearly distinct regions

Question 26

Mixed α /β

Answer 26

Motifs such as the α β α unit, where regions of α helix and β strand alternate or are interdispersed

Question 27

All α

Answer 27

Consist almost entirely of α helices & connecting loops

Question 28

Categories of protein structure

Answer 28

All β All α Mixed α /β α + β

Question 29

Aliphatic amino acids include

Answer 29

``` glycine alanine valine leucine isoleucine ```

Question 30

Aromatic amino acids

Answer 30

phenylalanine tyrosine tryptophan histidine

Question 31

sulfure containing amino acids

Answer 31

cysteine | methionine

Question 32

basic amino acids

Answer 32

lysine histidine arginine

Question 33

acidic amino acids

Answer 33

aspartate | glutamate

Question 34

amide versions of acidic amino acids

Answer 34

asparagine | glutamine

Question 35

alcohol amino acids

Answer 35

tyrosine serine threonine

Question 36

What is the most common structural motif in membrane proteins

Answer 36

spanning α-helices

Question 37

Valence shell

Answer 37

Outer electron shell

Question 38

Ligase

Answer 38

Enzyme which catalyses the joining of two substrates using ATP.

Question 39

Competitive inhibitor on kinetic constants

Answer 39

Bind to enzyme active site and raises Km value for enzyme

Question 40

Enzyme which cayalyses conversion of 2ADP to ATP and AMP

Answer 40

Adenylate Kinase

Question 41

How much free energy is released in ATP hydrolysis under normal physiological conditions?

Answer 41

Much more negative than ΔG°

Question 42

Which coenzyme is an oxidising agent used in catabolic reactions?

Answer 42

NAD+

Question 43

Which coenzyme is a reducing agent used in anabolic reactions?

Answer 43

NADPH

Question 44

First substance in glycolysis chain

Answer 44

GLucose

Question 45

Enzyme which converts glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate

Answer 45

GAPDH

Question 46

Enzyme which converts 1,3-bisphosphoglycerate to 3-phosphoglycerate

Answer 46

Phosphoglycerate kinase

Question 47

Enzyme involved in conversion of 3-phosphoglycerate to 2-phosphoglycerate during glycolysis

Answer 47

Phosphoglycerate mutase

Question 48

enzyme involved in conversion of 2-phosphoglycerate to Phosphoenolpyruvate during glycolysis

Answer 48

Enolase

Question 49

Enzyme which converts Phosphoenolpyruvate to pyruvate during glycolysis

Answer 49

Pyruvate kinase

Question 50

Other than glucose, what goes into glycolysis?

Answer 50

2 ADP + 2 NAD+ + 2 Pi

Question 51

Other than 2 pyruvate, what is produced during glycolysis

Answer 51

2 ATP | 2 NADH

Question 52

Equation for anaerobic metabolism of pyruvate to form ethanol

Answer 52

Glucose (6C) + 2 ADP + 2 Pi + 2 H+ --> 2 Ethanol (2C) + 2 ATP + 2 CO2 + 2 H2O

Question 53

What enzyme converts pyruvate to lactate?

Answer 53

Lactate dehydrogenase

Question 54

what enzymes are involved in conversion of pyruvate to ethanol?

Answer 54

Pyruvate decarboxylase | Alcohol dehydrogenase

Question 55

Intermediate in alcoholic fermentation?

Answer 55

Acetaldehyde

Question 56

What regenerate NAD+ after use in lactic acid fermentation?

Answer 56

Glyceraldehyde 3-phosphate dehydrogenase in glycolysis

Question 57

Activators of PFK-1

Answer 57

AMP and Fructose-1,6-bisPhosphate

Question 58

Inhibitors of PFK-1

Answer 58

ATP and citrate

Question 59

The main regulatory step in glycolysis is that catalysed by:

Answer 59

Phosphofructokinase (step 3)

Question 60

Folding of polypeptide chain into secondary structure is accompanied by....

Answer 60

Negative free energy change

Question 61

What is the main driving force for protein folding?

Answer 61

Increase in entropy due to reorganization of associated water molecules

Question 62

During aerobic respiration, pyruvate from the glycolysis pathway enters the mitochondrial matrix via...

Answer 62

Co-transport with protons through a translocase