Cell Metabolism 2

Question 1

What are the five main classes of lipids?

Answer 1

Free Fatty acids
Triacyglycerols
Phospholipids
Glycolipids
Steroids
-Fatty acids can either be saturated or unsaturated
Usually stored in cytoplasm of cells in form of triacylglycerols (three fatty acids attached with glycerol molecule and these attachments are via ester linkages), linkages help to neutralise carboxylic acid groups and so keep pH within cells normal range
Fatty acids are reduced and anhydrous making them ideal storage molecules

Question 2

What are bile salts?

Answer 2

• Bile salts are generated by liver and stored in the gallbladder
• During digestion pass form the bile duct into the intestine, emulsify fats in intestine aiding their digestion and absorption of fats and also that of fat soluble vitamins e.g. A, D, E and K
• A lack of bile slats results the majority of fat passing through the gut, undigested and unabsorbed resulting in steatorrhea

Question 3

What are sources?

Answer 3

Sources:
-acetyl CoA produced from both types of major food molecules within mitochondria of cell
-Therefore it is the location where most of the cellular oxidation reactions occur and also where the majority of cellular ATP is made
Sources:
1. Diet
2. De novo biosynthesis (lives
3. Storage deposits in adipose

Question 4

What is the anatomy of chylomicron?

Answer 4

• Digested dietary products are absorbed by enterocytes that line brush border of small intestine
• Triglycerides resynthesisied under control of several enzymes prior to incorporation into chylomircons (CM)
• These are transported via lymphatics and on into the bloodstream
• Acquire apoproteins from HDL following relates into the blood stream

Question 5

What is lipoprotein lipase?

Answer 5

• Chylomicrons (CMs) travel from lacteals of the intestine to the thoracic duct and to the left subclavian vein where they enter the blood stream
• Lipoprotein lipase is located ont he capillary endothelial cells lining a variety of tissues including adipose heart and skeletal muscle
• Fatty acids undergo beta oxidation glycerol is returned to the liver for use in gluconeogenisis

Question 6

What is the anatomy of lipoprotein?

Answer 6

Lipoproteins solve the problem of transporting hydrophobic molecules in an aq environment
Phospholipid monolayer containing cholesterol and apoproteins
This surrounds a core of cholesterol esters and tracylcglyerides

Question 7

What is HDL and LDL?

Answer 7

• HDLs good cholesterol education tot are cholesterol from peripheral tissues back to the liver for use or disposal (reverse cholesterol transport) and they help to lower total serum cholesterol
• LDLs bad cholesterol as prologoned elevation of LDLlevels leads to atherosclerosis (hardening of the arteries)
• LDLs transport cholesterol synthesised in the liver to peripheral tissue with more than 40% of their weight made up of cholesterol esters

Question 8

What is carnitine shuttle?

Answer 8

• Generation of Acyl CoA species occurs on the outer mitochondrial membrane
• To transport the species into the matrix it is couple to the molecules canritine to rom acyl carnitine
• Carnitine and Acyl carnitine are moved to and from the matrix by a trasnlocase