Chapter 11 Self-test questions

. Which of the following statements about glycogen breakdown is correct?

Glycogen phosphorylase hydrolyses glucose from the reducing end of a glycogen chain.

Glucose-6-phosphatase is present in liver but not in muscle.

Glucose-6-phosphatase is present in muscle but not in liver.

Glycogen phosphorylase splits off glucose from the nonreducing end of a glycogen chain.

. Which of the following statements about glycogen synthesis is correct?

Glycogen synthesis occurs at the reducing end of glycogen chains.

Phosphoglucomutase drives glycogen synthesis because the reaction has a large negative ?G⁰'.

Glycogen synthesis occurs when there is a high insulin to glucagon ratio.

Glycogen synthesis occurs when there is a high glucagon to insulin ratio.

. Which of the following statements about galactose is correct?

Galactose cannot be metabolised and remains in our blood after we consume milk.

Galactose is a glucose epimer that can be used as a substrate by the enzymes that use glucose as a substrate.

Galactose and fructose are isomers of glucose and can easily be interconverted.

Galactosaemia is a serious genetic disease that requires the removal of galactose from the diet of newborn infants.

. Which of the following statements about the enzymes, glucokinase, and/or hexokinase is correct?

Glucokinase has a high affinity for glucose.

Hexokinase has a high affinity for glucose.

Hexokinase has a higher K_mfor glucose than has glucokinase.

Glucokinase has a lower K_mfor glucose than has hexokinase.

. Which of the following statements about circulating lipoproteins is correct?

Chylomicrons release cholesterol to adipose tissues.

VLDL release cholesterol to the liver.

Chylomicrons contain mainly dietary triacylglycerols in their core.

LDL contain mainly dietary triacylglycerols in their core.

. Glycogen is degraded by the action of which type of enzyme?

A decarboxylase.

A phosphorylase.

A thiolase.

A kinase.

. What is the metabolic advantage of having a branched as opposed to a linear structure of glycogen?

It has a more compact structure.

It can be degraded faster as there are many starting points for enzymes to work at.

It can be degraded more slowly so avoiding a rush of glucose into the blood.

It is better hydrated.

. Statins are drugs taken to lower blood cholesterol. What is their mode of action?

They activate hormone sensitive lipase.

They inhibit lipoprotein lipase.

They inhibit HMG CoA reductase.

They inhibit lecithin-cholesterol acyl transferase.

. Which of the following statements about high density lipoprotein (HDL) is correct?

HDL lipoproteins are only synthesized in the liver.

HDL lipoproteins transport triacylglycerols to peripheral tissues.

HDL lipoproteins pick up cholesterol and convert it to cholesterol ester.

HDL lipoproteins cannot be endocytosed by the liver.

. Which enzyme allows the transfer of fatty acids from circulating chylomicrons and very low-density lipoprotein to peripheral cells such as muscle and adipose tissue?

Pancreatic lipase.

Lipoprotein lipase.

Hormone sensitive lipase.

Colipase.

. What is the cause of the condition known as familial hypercholesterolaemia?

Mutation in the B-100 receptor.

A diet high in saturated fat and cholesterol.

Inhibition of breakdown of fibrin clots by lipoprotein (a).

Mutation in apoprotein B-100 on low density lipoprotein.

. Which hormone involved in lipid metabolism is activated by glucagon and inhibited by insulin?

Lipoprotein lipase.

Pancreatic lipase.

Hepatic lipase.

Hormone sensitive lipase.

Chapter 11 Self-test questions

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