Lipid & Amino Acid Metabolism

Question 1

What occurs when lipids are transported into the small intestine during digestion & into the duodenum ?

Answer 1

Emulsification (mixing of immiscible substances)

-Aided by bile & cholesterol

Question 2

A fall in insulin levels activates Hormone-sensitive lipase which functions to do what ?

Answer 2

Hydrolyze triacylglycerols (to yield glycerols & fatty acids)

• Activated by epinephrine & cortisol
• Effective within adipose cells

Question 3

What is lipoprotein lipase necessary for ?

Answer 3

Metabolism of chylomicrons & VLDL

Question 4

Chylomicrons function in the transport of what ?

Answer 4

Dietary triacyls, cholesterol, & cholesteryl esters to other tissues
*Assembly occurs in intestinal lining

Question 5

VLDL is similar to chylomicrons in function but differs in that it is ?

Answer 5

Produced in liver cells

Question 6

Once TG is removed from VLDL, the resulting particle is referred to as ?

Answer 6

IDL or VLDL remanent

*Can be reabsorbed or transferred to LDL by HDL

Question 7

The majority of cholesterol measured in the blood is associated w/ ?

Answer 7

LDL: delivers cholesterol to tissues for biosynthesis

Question 8

What is synthesized in the liver & intestines, & is released into the blood as dense protein-rich particles ?

Answer 8

HDL: cleans up excess cholesterol & delivers cholesterol to steroidogenic tissues

Question 9

The synthesis of mevalonic acid in the SER is the RLS of what ?

Answer 9

Cholesterol biosynthesis

*Catalyzed by HMG CoA reductase

Question 10

Polyunsaturated fatty acids that are essential for maintaining membrane fluidity are known as ?

Answer 10

a-linoleic & linoleic acids

Question 11

What is the rate limiting enzyme of fatty acid biosynthesis ?

Answer 11

Acetyl-CoA carboxylase

Question 12

The large multienzyme complex found in the cytosol that is rapidly induced by spikes in insulin is known as ?

Answer 12

Fatty acid synthase

Question 13

The rate limiting enzyme of fatty acid oxidation is ?

Answer 13

Carnitine acyltransferase I

Question 14

What are the 4 steps of b-oxidation?

Answer 14

1. Oxi of fatty acid to form =
2. Hydration of = to form OH
3. Oxi of OH to form carbonyl (b-ketoacid)
4. Splitting of b-ketoacid into 2actyl-CoA

Question 15

What 2 extra enzymes are needed in oxidation of unsaturated fatty acids ?

Answer 15

Enoyl-CoA isomerase: rearranges cis = @ 3,4 position to trans @ 2,3 position
2,4-Dienoyl-CoA reductase: convert 2 conjugated = @ 3,4 to 2,3 position

Question 16

Ketone bodies are essentially…?

Answer 16

Transportable acetyl coA (produced by liver & used by other tissues during prolonged starvation)