Cholesterol Flashcards
Why is fat important in the diet?
It provides energy, essential fatty acids and fat soluble vitamins
How many fatty acid chains are there in triglycerols?
Three
How many fatty acid chains are there in phospholipids?
Two
How many fatty acid chains are there in cholesterol?
One
What is the difference between saturated and unsaturated fats?
Saturated fats contain no carbon to carbon double binds whereas unsaturated fats contain at least one carbon to carbon double bond
What is the difference between a cis and trans saturated fat?
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
What foods are high in saturated fats?
Meat products
Hard cheese
Butter
Lard
What fiods are rich in cis unsaturated fats?
Vegetable oils Olive oil Oily fish Nuts Seeds Abocados
What foods are rich in trans unsaturated fats?
Biscuits, cakes, deep fried fast food, pastry
What factor influence blood lipid levels?
Family history and genetics Gender Body weight Physical activity Diet
Which modifiable factor is considered most important in the blood level of lipids?
Diet
Lipids are insoluble in water and plasma. So how are they transported in blood?
As lipoproteins
What is the composition of a lipoprotein?
A central core of a neutral lipid /(triglyceride or cholesterol esters) surrounded by a polar coat of phospholipids, free cholesterol and apoproteins
Which lipoprotein is least dense, carries mainly triglycerides from the intestines to the adipose tissue and muscle and contains the apoprotein b48?
Chylomicron
Which lipoprotein transports triglyceride from the liver to adipose tissue and muscle and contains the apoprotein B100?
Very low density lipoprotein
Which lipoprotein transports cholesterol from the liver to tissues and contains the apoprotein B100?
Low density lipoprotein
Which lipoprotein carries mainly cholesterol from the tissues to the liver and contains the apoproteins A1 and A2?
High density lipoprotein
What are the functions of lipoproteins?
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
What effect does increased cholesterol have on CHD risk?
Increases CHD risk
What effect does increased HDL have on CHD risk?
Decreased CHD risk
How does HDL effect CHD risk?
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
Why does an increase in triglyceride increase CHD risk?
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
How does the intracellular concentration of cholesterol affect blood cholesterol levels?
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
Which enzyme utilises unsaturated fatty acids for the production of cholesterol esters?
Aceyl-coA-cholesterol acyltransferase (ACAT)
How does the activity if the enzyme ACAT effect blood cholesterol concentration?
Increased activity of ACAT decreases intracellular cholesterol levels to cause LDL receptor upregulation and a fall in blood cholesterol levels
What type of fatty acids are poor substrates for ACAT and therefore cause an increase in blood cholesterol levels?
Saturated fatty acids
