Principles

Question 1

How does glucose enter cells?

Answer 1

Via the sodium glucose symporters

Question 2

What does hexokinase do to glucose?

Answer 2

Turns it to glucose 6-phosphate

Question 3

What does phosphofructokinase do to fructo 6-phosphate?

Answer 3

Turns it to fructo 1,6-biphosphate

Question 4

Pyruvate kinase is needed to make what?

Answer 4

Pyruvate

Question 5

The three enzymes controlling irreversible pathways in glycolysis

Answer 5

Hexokinase, phosphofructokinase, pyruvate kinase

Question 6

What is derived from niacin?

Answer 6

NAD+

Question 7

What is regenerated through the metabolism of pyruvate?

Answer 7

NAD+

Question 8

Where are the enzymes of the TCA cycle located?

Answer 8

The mitochondrial matrix, except succinate dehydrogenase which is located in the inner membrane

Question 9

How many NADH + H+ and FADH2 produced in each turn of the TCA cycle?

Answer 9

3 NADH + H+ and 1 FADH2

Question 10

What can pyruvate be converted to?

Answer 10

Alcohol, lactate, acetyl coA

alcohol dehydrogenase, lactate dehydrogenase

Question 11

What catalyses the oxidative phosphorylation of pyruvate to acetyl coA?

Answer 11

Pyruvate dehydrogenase complex

3 enzymes involved, 2 extra for control and 5 cofactors

Question 12

What is a major determination of glucose oxidation in well oxygenated tissues?

Answer 12

Pyruvate dehydrogenase complex (this reaction is irreversible lol)

Question 13

How many high energy electrons in NADH+/FADH2?

Answer 13

2

Question 14

How can the electron transfer potential be measured?

Answer 14

The redox potential/reduction potential of the compound

Question 15

How can the phosphoryl transfer potential be measured?

Answer 15

The free energy change for the hydrolysis of ATP

Question 16

What does a negative E’o mean?

Answer 16

Lower affinity for electrons than hydrogen

Question 17

What is the standard free energy change proportional to?

Answer 17

The change in standard redox potential and the number of electrons transferred.

Question 18

What is the change in standard redox potential and number of electrons transferred proportional to?

Answer 18

The change in free energy

Question 19

How many of the 4 respiratory pumps, pump H+?

Answer 19

3

Question 20

At which complex does FADH2 enter?

Answer 20

Complx 2 (this is part of the TCA cycle)

Question 21

What do the respiratory chain proton pumps do?

Answer 21

Pump protons into the intermembrane space

Question 22

How do protons flow back through from the intermembrane space to the inner matrix?

Answer 22

Through ATP synthase

Question 23

The importance of the haem group in cytochrome?

Answer 23

Picks up and releases electrons

Question 24

The glycerol-3-phosphate and malate shuttles are used to do what?

Answer 24

Transport NADH from the cytoplasm into the inner mitochondrial membrane

Question 25

ATP yield from 1 glucose molecule?

Answer 25

30-32 molecules (depends on exact P/O ration and which shuttle was used)

Question 26

What is a hydrophobic interaction?

Answer 26

The interaction between a polar substance and a non-polar substance

Question 27

What is a van der Waals interaction?

Answer 27

Interaction of electrons between non-polar substances

Question 28

What is acylation?

Answer 28

Addition of an acyl group (RCO)

Question 29

Electrons are transferred from propane to oxygen to form what?

Answer 29

Water

Question 30

First law of thermodynamics?

Answer 30

Energy is neither created nor destroyed

Question 31

Second law of thermodynamics?

Answer 31

When energy is converted from one form to another, some of that energy becomes unavailable to do work

Question 32

What is a change in enthalpy?

Answer 32

A change in heat content H

Question 33

What is a change in entropy?

Answer 33

A change in order/randomness S

Question 34

What are exogernic reactions?

Answer 34

Reactions where the free energy of the products is greater than that of the reactants These reactions can occur spontaneously

Question 35

Why is pH 7 included in standard conditions?

Answer 35

Because pH 0/ 1 mol H+ is extremely acidic for the human body

Question 36

^G values near 0 are characteristic of what?

Answer 36

Readily reversible reactions | Also remember, the closer a reaction is to equilibrium, the more free energy is released

Question 37

What does phosphoglucomutase do?

Answer 37

Catalyses the reaction of glucose 1-phosphate to glucose 2-phosphate and vice versa

Question 38

What do you do if the process is unfavourable?

Answer 38

Couple it to a favourable one (i.e one with a negative free energy change. A bit like hi-jacking) This is why ATP is used as a universal energy current

Question 39

Where will you find high energy anhydride bonds?

Answer 39

ATP

Question 40

Are reactions with ^G close to 0 used as control points?

Answer 40

No. Reactions with fairly large negative ^G values are used as control points. Flux through these points is controlled by altering the activity of the enzyme involved

Question 41

What does the acid dissociation (Ka) constant measure?

Answer 41

How readily an acid donates a proton

Question 42

Buffers and their pKa values?

Answer 42

When buffers are close to their pKa value, they tend to resist a change in pH upon small additions of acid/base

Question 43

What plots pH as a function of base to acid added?

Answer 43

A titration curve

Question 44

Zwitterions?

Answer 44

Lol a molecule without charged side groups i.e amino acids (these can be used as buffers)

Question 45

What is the isoelectric pH?

Answer 45

The pH at which an molecule has no net charge

Question 46

Why do amino acids have 2 pKa values?

Answer 46

Because they have 2 titratable groups

Question 47

Which angles can peptides rotate around?

Answer 47

The angle between the C and the carboxyl group | The angle between the C and the amino group

Question 48

What does proline do to alpha helices?

Answer 48

Breaks them

Question 49

What does the enzyme which carboxylates proline need?

Answer 49

Vitamin C

Question 50

What type of protein is collagen?

Answer 50

A fibrous protein

Question 51

Are globular proteins soluble in water?

Answer 51

Yes, most of their polar side chains are on the outside Nearly all have masses of alpha helix and beta sheets Fibrous proteins are not soluble in water

Question 52

What are involved in sulphide bond formation?

Answer 52

Cysteine molecules (SH)

Question 53

What contains repeating sequences of X, Y and Gly?

Answer 53

Tropocollagen

Question 54

Does collagen contain inta-chain H bonds?

Answer 54

No, only inter-chain H bonds

Question 55

In which condition does a mutation so that valine is produced instead of glutamic acid? (single nucleotide sequence change)

Answer 55

Sickle cell anemia | valine interacts with other hydrophobic amino acids

Question 56

What are chaperone proteins?

Answer 56

Proteins which aid protein folding

Question 57

How do thiol agents (reducing agents) disrupt protein structure?

Answer 57

Reduce and therefore disrupt disulphide bonds

Question 58

ATP, citrate and H+ are negative modulators of what?

Answer 58

Phosphofructokinase | AMP and fructose 2,6-biphosphate are positive modulators

Question 59

Adenylate kinase?

Answer 59

2ADP->ATP + AMP

Question 60

What is the 'energy charge'?

Answer 60

ATP/AMP ratio

Question 61

Succinate and FAD produce..?

Answer 61

Fumarate and FADH2