Metabolism

Question 1

Phenylketonuria is a disease caused by what?

Answer 1

A defective Phenylalanine hydroxylase.

Question 2

Neriminidase is what?

Answer 2

An anti-flu drug that prevents the viron from cleaving the cyclic-acid bond that attaches it to the cell wall, preventing migration.

Question 3

What are the three assumptions of the Michaelis-Menten theory?

Answer 3

1. [S] is far,far,far greater than [P] initially.
2. Steady state conditions.
3. [S] is far,far,far greater than [E]

These three combine to give the equation

E + S —K1– ES —K2– E + P

Question 4

Reversible inhibitors come in three category’s, explain?

Answer 4

Competitive: Attempts to bind the enzyme faster than the substrait, preventing reaction.

Uncompetitive: The inhibitor can only bind the enzyme using the substrait as a cofactor.

Mixed: This is between the two modes of inhibition. Binds with the substrait to the enzyme.

Question 5

What is the function of Kinase?

Answer 5

Kinases catalyses the transfer of phosphoryl groups from one molecule to another.

Question 6

What is the function of Phosphorylase?

Answer 6

Catalyses the addition of inorganic phosphate (Pi) to a molecule.

Question 7

What is the function of Phosphatase?

Answer 7

Phosphatase catalyses the cleavage of a phosphate to give the product and Pi.

Question 8

What is the function of Dehydrogenase?

Answer 8

Dehydrogenase catalyses a redox reaction that removes (or adds) a H from the substrait. It oxidises the substrait by reducing an E- acceptor usually NAD+/NADP+

Question 9

What is the function of Mutase?

Answer 9

Mutase catalyses the shift of a phosporyl group to another atom within the SAME molecule.

Question 10

What is the function of Isomerase?

Answer 10

Isomerase catalyses the conversion of one isomer to another.

Question 11

What is the function of Hydratase?

Answer 11

Hydratase catalyses the addition/removal of water from a molecule.

Question 12

What is the function of Synthase?

Answer 12

Synthase catalyses the synthesis of a product WITHOUT a high energy source (ATP,GTP)

Question 13

What is the function of Synthetase?

Answer 13

Synthetase catalyses the synthesis of a product USING a high energy source (ATP,GTP)

Question 14

Define “Anabolic pathway”

Answer 14

A metabolic pathway that uses chemical energy to make larger, more organised macromolecules.

Question 15

Define “Catabolic pathway”

Answer 15

A metabolic pathway that uses a little energy to make energy molecules and energy products.

Question 16

What is type 1 Diabetes?

Answer 16

Type 1 diabetes is an autoimmune disease that causes the destruction of pancreatic beta-cells.

Question 17

What is type 2 diabetes?

Answer 17

Type 2 diabetes is categorised by the cells not responding well to insulin or being actively resistant to it.

Question 18

What is the effect Adrenalin / Epinephrin has on metabolism?

Answer 18

Adrenalin binds to the Beta-adrenergic receptor which causes G-molecule signalling to activate adenylate cyclase which causes an activator cascade.

In the liver it up regulates gluconeogenesis and glycogenolysis.

In the muscles it up regulates glycolysis and glycogenolysis.

Question 19

What is Glucagon and what is it for?

Answer 19

Glucagon is the primary messenger in the pathway that increases blood glucose level, it has the opposite effect of insulin.

It is produced in the Alpha-pancreatic cells and is released into the liver if the blood glucose level drops below 4.5mM. In the liver it up regulates glyconeogenesis and glycolysis.

Question 20

How many glucose transporters do humans have and where are they?

Answer 20

Humans have 5 genes for glucose transporters.
GLUT 1: Is the general transporter found in all tissues
GLUT 2: Give out more than it imports, liver and pancreas.
GLUT 3: Used only by the neurones in the brain.
GLUT 4: Hormonally controlled in the muscles and fats.
GLUt 5: Mainly for fructose, small intestine.