Biochem- Lipids

Question 1

This is the molecule which has a glycerol backbone and 3 esterified FA’s attached to it.

Answer 1

Triacylglycerol (TG)

Question 2

TG’s are resynthesized in the epithelia from what 2 components?

Answer 2

FA’s + 2-monoacylglycerols

Question 3

Where in the cell are TG’s synthesized?

Answer 3

Smooth ER

Question 4

What is the intermediate structure that sits on the end of the fatty acids in the formation of TG?

Answer 4

acyl-CoA’s

Question 5

This is a the molecule that delivers endogenous lipids from the liver to the blood to the tissues.

Answer 5

VLDL

Question 6

In addition to TG’s, what 3 other things are packed in the VLDL?

Answer 6

cholesterol, phospholipids, and proteins.

Question 7

Matching:
A. Liver
B. Chylomicrons

1. Apo B-48
2. Apo B-100

Answer 7

A/2- Liver has Apo B-100
B/1- Chylomicrons have Apo B-42

(liver is bigger!)

Question 8

Lingual lipase digest what 2 length of fats?

Answer 8

short or medium chain

Question 9

At what age of life are lingual and gastric lipases activated? (hint: milk)

Answer 9

kids, cuz milk has a bunch of short and medium chain fatty acids

Question 10

So if the lingual lipase digests short and medium chain FA’s, where does the long chain start to be digested?

Answer 10

duodenum

Question 11

What emulsifies long chain FA’s in the duodenum?

Answer 11

bile salts

Question 12

Where are bile salts synthesized?

Answer 12

Liver

Question 13

Where are bild salts stored?

Answer 13

Gallbladder

Question 14

Which hormone causes contraction of the gallbladder when fat is ingested?

Answer 14

CCK

Question 15

What is the major enzyme to digest dietary lipids?

Answer 15

Pancreatic lipase

Question 16

Pancreatic lipase along with what other enzyme are secreted in response to CCK?

Answer 16

Colipase

Question 17

How does bile salts inhibit pancreatic lipase’s activity on fats?

Answer 17

They cockblock the lipase by not allowing access to the substrate

Question 18

What is the function of the colipases?

Answer 18

They bind to fat to relieve the bile salt restriction.

Question 19

What is the final product of the lipases digestion of TG?

Answer 19

2-acylglycerol. The middle finger.

Question 20

Where in the cell are the TG’s re-synthesized from FA’s and 2-MG?

Answer 20

Smooth ER

Question 21

What is the biggest component of the chylomicron?

Answer 21

TG’s

Question 22

What 4 other substances are in the chylomicron besides TG?

Answer 22

phospholipid, cholesterol ester, proteins, and cholesterol (in order from [most] to [least]

Question 23

Which to apoproteins are needed to convert the nascent chylomicro into a mature chylomicron?

Answer 23

ApoE and ApoCII

Question 24

What is the fxn of ApoE?

Answer 24

allows the chylomicron to bind to the liver once it delivers the tackage of TG’s to the tissues

Question 25

What is the fxn of ApoCII?

Answer 25

Activated LPL on adipose tissue

Question 26

So what is the molecular biological mechanism to make Apo B-48 from Apo B-100?

Answer 26

RNA editing

Question 27

Which pancreatic hormone stimulates the synthesis and secretion of adipose LPL?

Answer 27

Insulin

Question 28

Is the Km of the LPL in adipose tissue high or low?

Answer 28

High

Question 29

Is the Km of the LPL in muscle tissue high or low?

Answer 29

Low

Question 30

What does LPL do to the TG's in the chylomicron?

Answer 30

Degrade them to FA's

Question 31

Which enzyme is the rate limiting step in the synthesis of bile salts from cholesterol?

Answer 31

7a-hydroxylase

Question 32

What is 7a-hydroxylase inhibited by in the synthesis of bile salts?

Answer 32

bile salts (negative regulation!)

Question 33

What are the 2 molecules created for bile salts from cholesterol?

Answer 33

Chenodeoxycholic acid and cholic acid

Question 34

What is removed from the primary bile salts from bacteria to create secondary bile salts?

Answer 34

Glycine or taurine

Question 35

Where in the GI tract are bile salts reabsorbed?

Answer 35

ileum

Question 36

What % of bile salts are reabsorbed?

Answer 36

95%

Question 37

What will the urine and sclera look like in a bile duct blockage?

Answer 37

Urine is iced tea, sclera are jaundice.