Lipids & lipoproteins – 1

Question 1

What is the primary role of lipids?

Answer 1

Rich source of energy & efficient way to store calories

Question 2

What are the major types of lipids?

Answer 2

• Fatty acids (FA) * Triglycerides (TG) * Cholesterol (Chol) * Phospholipids (PL)

Question 3

What is the relationship between elevated plasma levels of lipids and health?

Answer 3

Pathogenesis of atherosclerosis

Question 4

How are lipids transported in the bloodstream?

Answer 4

Carried by complexes known as lipoproteins

Question 5

What are lipoproteins composed of?

Answer 5

• Phospholipids * Cholesterol * Proteins (outside) * Cholesteryl esters & triglycerides (inside)

Question 6

Define fatty acids (FA).

Answer 6

Linear chains of C-H bonds terminating in carboxyl group (COOH)

Question 7

In what form do most fatty acids exist in plasma?

Answer 7

Bound to albumin

Question 8

What is the structure of triglycerides (TG)?

Answer 8

3 FA attach to 1 molecule of glycerol by ester bonds

Question 9

What are phospholipids (PL) composed of?

Answer 9

• Glycerol * Phosphate * 2 fatty acyl chains in ester linkage

Question 10

How do phospholipids differ from triglycerides?

Answer 10

Phospholipids have only 2 esterified fatty acids

Question 11

What is the structure of cholesterol (Chol)?

Answer 11

An unsaturated steroid alcohol containing 4 rings & single side chain tail

Question 12

Where is the majority of cholesterol produced?

Answer 12

75% is made in the liver

Question 13

What is the function of apolipoproteins?

Answer 13

Bind lipids such as cholesterol to form lipoproteins

Question 14

List the major types of lipoproteins.

Answer 14

• Chylomicrons * VLDL (very low density lipoproteins) * IDL (intermediate density lipoproteins) * LDL (low density lipoproteins) * HDL (high density lipoproteins)

Question 15

What is the primary function of chylomicrons?

Answer 15

Deliver dietary lipids to hepatic & peripheral cells

Question 16

What is the composition of very-low-density lipoproteins (VLDL)?

Answer 16

Rich in triglycerides (70%)

Question 17

What happens to intermediate density lipoproteins (IDL)?

Answer 17

• Taken up by the liver * Reduced to LDL

Question 18

What characterizes low-density lipoproteins (LDL)?

Answer 18

Rich in cholesterol and can infiltrate to extracellular space

Question 19

What is the atherogenic potential of LDL?

Answer 19

Activates monocytes and provides cholesterol for macrophages in atheromatous plaques

Question 20

What is atheromatous plaque composed of?

Answer 20

• Macrophages * Debris containing lipids * Calcium * Fibrous connective tissue

Question 21

What is the function of high-density lipoproteins (HDL)?

Answer 21

Removes excess cholesterol from peripheral cells and returns it to the liver

Question 22

What is the significance of HDL in cardiovascular health?

Answer 22

Potential to help reverse heart diseases

Question 23

What is the difference in lipid levels between men and women?

Answer 23

Women have higher HDL cholesterol levels but lower total cholesterol & TG levels than men

Question 24

What factors influence total, LDL-cholesterol & triglyceride levels?

Answer 24

Increase with age in both men & women

Question 25

What are common methods for cholesterol measurement?

Answer 25

* Hydrolysis with KOH * Hexane extraction * Reaction with Liebermann-Burchard color reagent

Question 26

What is the most common method for LDL measurement?

Answer 26

β-quantification

Question 27

What are apolipoprotein methods used for?

Answer 27

Measure Apo B & Lp(a) directly in serum by immunoassay

Question 28

Fill in the blank: Lipoproteins according to the density are ordered as _______.

Answer 28

HDL > LDL > IDL > VLDL > CM

Question 29

Fill in the blank: The main types of lipoproteins are _______.

Answer 29

Chylomicrons, VLDL, IDL, LDL, HDL

Question 30

True or False: Cholesterol is readily utilized by most cells.

Answer 30

False