Cholesterol

Question 1

Why is fat important in the diet?

Answer 1

It provides energy, essential fatty acids and fat soluble vitamins

Question 2

How many fatty acid chains are there in triglycerols?

Answer 2

Three

Question 3

How many fatty acid chains are there in phospholipids?

Answer 3

Two

Question 4

How many fatty acid chains are there in cholesterol?

Answer 4

One

Question 5

What is the difference between saturated and unsaturated fats?

Answer 5

Saturated fats contain no carbon to carbon double binds whereas unsaturated fats contain at least one carbon to carbon double bond

Question 6

What is the difference between a cis and trans saturated fat?

Answer 6

Cis unsaturated fats have hydrogen atoms on the same side of the double bond whereas trans unsaturated fats have hydrogen atoms on the opposite side of the double bond

Question 7

What foods are high in saturated fats?

Answer 7

Meat products
Hard cheese
Butter
Lard

Question 8

What fiods are rich in cis unsaturated fats?

Answer 8

Vegetable oils
Olive oil
Oily fish
Nuts
Seeds
Abocados

Question 9

What foods are rich in trans unsaturated fats?

Answer 9

Biscuits, cakes, deep fried fast food, pastry

Question 10

What factor influence blood lipid levels?

Answer 10

Family history and genetics
Gender
Body weight
Physical activity
Diet

Question 11

Which modifiable factor is considered most important in the blood level of lipids?

Answer 11

Diet

Question 12

Lipids are insoluble in water and plasma. So how are they transported in blood?

Answer 12

As lipoproteins

Question 13

What is the composition of a lipoprotein?

Answer 13

A central core of a neutral lipid /(triglyceride or cholesterol esters) surrounded by a polar coat of phospholipids, free cholesterol and apoproteins

Question 14

Which lipoprotein is least dense, carries mainly triglycerides from the intestines to the adipose tissue and muscle and contains the apoprotein b48?

Answer 14

Chylomicron

Question 15

Which lipoprotein transports triglyceride from the liver to adipose tissue and muscle and contains the apoprotein B100?

Answer 15

Very low density lipoprotein

Question 16

Which lipoprotein transports cholesterol from the liver to tissues and contains the apoprotein B100?

Answer 16

Low density lipoprotein

Question 17

Which lipoprotein carries mainly cholesterol from the tissues to the liver and contains the apoproteins A1 and A2?

Answer 17

High density lipoprotein

Question 18

What are the functions of lipoproteins?

Answer 18

Transporting lipids
Giving structural identity to the lipoprotein particle
Identifying the type of lipid in the lipoprotein
Regulating the metabolism and uptake of lipids into cells

Question 19

What effect does increased cholesterol have on CHD risk?

Answer 19

Increases CHD risk

Question 20

What effect does increased HDL have on CHD risk?

Answer 20

Decreased CHD risk

Question 21

How does HDL effect CHD risk?

Answer 21

HDL clears cholesterol from the bloodstream meaning that there is less cholesterol in the blood to become oxidised, leading to fewer foam cells and atherosclerotic plaques

Question 22

Why does an increase in triglyceride increase CHD risk?

Answer 22

High triglyceride levels are associated with more small, dense LDL particles which are more susceptible to oxidation. Than HDL particles and can lead to the formation of atherosclerotic plaques

Question 23

How does the intracellular concentration of cholesterol affect blood cholesterol levels?

Answer 23

If intracellular cholesterol levels fall then LDL receptors are upregulated and more cholesterol is taken up by cells, causing the blood cholesterol concentration to fall

Question 24

Which enzyme utilises unsaturated fatty acids for the production of cholesterol esters?

Answer 24

Aceyl-coA-cholesterol acyltransferase (ACAT)

Question 25

How does the activity if the enzyme ACAT effect blood cholesterol concentration?

Answer 25

Increased activity of ACAT decreases intracellular cholesterol levels to cause LDL receptor upregulation and a fall in blood cholesterol levels

Question 26

What type of fatty acids are poor substrates for ACAT and therefore cause an increase in blood cholesterol levels?

Answer 26

Saturated fatty acids