Revision

Question 1

What is vmax?

Answer 1

Vmax is the maximum rate of an enzyme catalysed reaction i.e. when the enzyme is saturated by the substrate.

Question 2

What is KM?

Answer 2

Km is measure of how easily the enzyme can be saturated by the substrate.

Question 3

What are Coenzymes?

Answer 3

Coenzymes are a subset of cofactors that are organic (carbon-based) molecules. The most common sources of coenzymes are dietary vitamins.

Question 4

If you are being chased by a tiger,

Answer 4

Your muscle cells will be running glycolysis, and your liver cells will running gluconeogenesis.

Question 5

Which of these is tested for by the heel prick test at birth?

Answer 5

Cystic fibrosis
Sickle-cell disorders
Phenylketonuria
Medium chain acyl CoA dehydrogenase (MCAD) deficiency

Question 6

In what part of the eukaryotic cell is oxidative phosphorylation carried out?

Answer 6

Inner mitochondrial membrane

Question 7

Diabetics often suffer __________, a condition in which acetoacetate levels increase, causing sweet breath odour.

Answer 7

Ketosis

Question 8

What pumps protons?

Answer 8

Complex III
Complex I
Complex IV

Question 9

A good biomarker is…

Answer 9

Not present in the assay of a normal individual
Specific for a particular tissue
Change proportionally to the disease severity
Is functionally stable and easy to assay

Question 10

The carbon skeletons from excess protein ingestion can be used in the following process(es):

Answer 10

ATP generation
Fat synthesis
Glucose synthesis
Formation of other amino acids

Question 11

Which of the following proteins forms the glycogen ‘primer’?

Answer 11

Glycogenin forms the glycogen ‘primer’

Question 12

Which chemicals uncouples electron transport from ATP synthesis?

Answer 12

2,4-dinitrophenol (DNP)

Question 13

Which of the following are effects of insulin secretion?

Answer 13

Muscle and adipose tissue are stimulated to take up glucose.

Gluconeogenesis is inhibited in the liver.

Synthesis of glycogen, proteins, and triacylglycerols are stimulated, promoting cell growth.

Question 14

In the urea cycle, the second nitrogen of urea enters the cycle in the form of which metabolite?

Answer 14

aspartate

Question 15

Which one of these enzyme catalyses the reduction of oxygen to water?

Answer 15

cytochrome c oxidase

Question 16

Muscle does not respond to glucagon by breaking down glycogen stores. This is because ______

Answer 16

Muscle lacks the receptor for glucagon.

Question 17

During prolonged starvation, what is true?

Answer 17

The breakdown of triacylglycerides will produce both ketone bodies and glucose.

The brain will switch to using ketone bodies as an energy source.

Question 18

The glycerol released from lipolysis in starvation is important because it is used to make:

Answer 18

glucose in the liver by gluconeogenesis.

Question 19

In glycogen synthesis, the intermediate between glucose-1-phosphate and glycogen is:

Answer 19

UDP–glucose (uridinediphosphate-glucose).

Question 20

Statements about oxidative phosphorylation

Answer 20

A proton gradient across the inner mitochondrial membrane can be used to generate heat.

A proton gradient across the inner mitochondrial membrane powers mitochondrial membrane transporters.

Electron transport provides energy to pump protons into the inter-membrane space.

An electrochemical gradient is formed across the inner mitochondrial membrane.

Question 21

Increased levels of glucagon in the blood will:

Answer 21

stimulate glycolysis in the liver cell

Question 22

Statements about glycogen?

Answer 22

In glycogen breakdown, glucose residues are sequentially removed from the non-reducing ends.

The breakdown of glycogen in skeletal muscle ultimately supplies glucose-6-phosphate, which can enter glycolysis to generate ATP.

Glycogen is the storage polysaccharide in skeletal muscle and liver cells.

Glycogen is a polymer of glucose of alpha(1,4) linkages with alpha(1,6) linked branches every 8–14 residues.

Question 23

Metabolic disorders that inhibit urea synthesis can cause a potentially fatal coma due to a drop in neuronal ATP production because of:

Answer 23

A rise in ammonia levels depletes the TCA cycle of alpha-ketoglutarate

Question 24

In animals, what cannot be used for glucose production.?

Answer 24

Fatty Acids

Question 25

Which of the following best describes the function of the glycogen debranching enzyme in glycogenolysis?

Answer 25

It transfers an alpha (1-4) linked trisaccharide unit from a limit branch to the non-reducing end of another branch, and then cleaves the alpha (1-6) branch point releasing
glucose.

Question 26

In the fed state, which of these is an unlikely metabolic route for glucose-6-phosphate in the liver?

Answer 26

Gluconeogenesis and release of glucose into the plasma.

Question 27

Which diets would most likely promote the formation of ketone bodies

Answer 27

high protein and high fats

Question 28

A true statement about isoenzymes

Answer 28

they have tissue specific expression patterns

Question 29

True statement about Ubiquinone and cytochrome c

Answer 29

about Ubiquinone and cytochrome c is TRUE?

Question 30

In the urea cycle, the second nitrogen of urea enters the cycle in the form of which metabolite?

Answer 30

aspartate

Question 31

What is a point mutation?

Answer 31

Change in a single base pair in DNA

Question 32

Types of inhibition

Answer 32

competitive, noncompetitive, and uncompetitive.

Question 33

What is a Silent mutation?

Answer 33

If a base change does not change the amino acid at that codon (e.g. CCU - CCC as both encode proline)



Question 34

What is a Missense mutation?

Answer 34

When the mutation causes the incorporation of a different amino acid 
(e.g. CCU – CUU causes leucine in place of proline

Question 35

What is a Nonsense mutation?

Answer 35

When the mutation changes the codon to STOP, thus the protein is truncated (UAC – UAA causes STOP in place of tyrosine)

Question 36

What is a Nonsense mutation?

Answer 36

When the mutation changes the codon to STOP, thus the protein is truncated (UAC – UAA causes STOP in place of tyrosine)

Question 37

What is a apoprotein?

Answer 37

A protein without its prosthetic group is called an apoprotein

Question 38

What is a holoprotein?

Answer 38

A protein combined with its prosthetic group is called a holoprotein