Micro - Westerick - Lipid Metab. Triglyceride Synthesis And Breakdown Fa-B-Ox.

Front 1

How are fatty acids stored?

Back 1

triglycerides

Front 2

How are FAs transported to adipose

Back 2

Triglyceride components of lipoproteins

Front 3

How are FAs transported from adipose?

Back 3

bound to albumin

Front 4

Can triglycerides cross plasma membranes?

Back 4

no, triglyceride FA components cross plasma membranes. TGs are resynthesized on the other side of the membrane using a dif. glycerol backbone and the same FAs. (= an ongoing process)

Front 5

The glycolitic compound which can be converted to glycerol-3-P is?

Back 5

IN LIVER: glycerol
ANYWHERE ELSE: Dihydroxyacetone-P

Front 6

List the steps needed to get to a Triglyceride

Back 6

GLYCOLYSIS: Glucose--> Glu-6-P --> Fruc-6-P --> Fruc1,6 BisP --> (via adolase) Dihydroxyacetone-P <--> Glycerol-3-P --> Phophatidic Acid --> Diacylglycerol --> Triacylglycerol

Front 7

Detail the process of FA activation in the Liver

Back 7

In liver ONLY, glycerol (from triglyceride lipolysis) may be re-phosphorylated to glycerol-3-P and used for triglyceride synthesis or for other purposes. glycerol --> glycerol-3-P

Front 8

Detail the process of FA activation in extrahepatic cells AND hepatic cells

Back 8

glucose --> dihydroxyacetone-P (via glycolysis) --> glycerol-3-P (via glycerol-3-P dehydrogenase) for triglyceride synthesis

Front 9

State the steps of the link from glycolysis to FA synthesis

Back 9

Dihydroxyacetone-P --> Glycerol-3-P (via glycerol-3-P dehydrogenase) Alot of NADH drive rxn FWD b/c of NADH buildup in glycolysis

also: the reverse rxn can happen:
Dihydroxyacetone-P <-- Glycerol-3-P (via glycerol-3-P dehydrogenase)

Front 10

What are the sources of glycerol-3-P... in the Liver? in the Liver and Adipose Tissue?

Back 10

Liver: Glycerol (end product = Blood VLDL)
Liver and Adipose: Glucose (end product = Adipose Stores)

Front 11

How does Triacylglycerol in mucosal cells differ from other triacylglycerol synthesis?

Back 11

It starts with monoacylglycerol instead of glycerol-3-P

Front 12

What synthesizes the removal of FA groups from triglyceride molecules?

Back 12

The Lipases: Pancreatic, Lipoprotein, and Adipose (hormone sensitive) lipase

Front 13

Where does the pancreatic lipase stop in the removal of FA groups from triglyceride molecules?

Back 13

monoacylglycerol

Triacylglycerol --> Diacylglycerol --> Monoacylglycerol --> Glycerol

Front 14

Which lipases are active in the FED state?

Back 14

Pancreatic Lipase and Lipoprotein Lipase

Front 15

What is the function of pancreatic lipase?

Back 15

Breaks down dietary triglycerides to free FAs and monoacylglycerol

Front 16

What are the products of Pancretic Lipase used for?

Back 16

They cross the mucosal cell membranes and then are used to synthesize chylomicron (a lipoprotein) triglycerides

Front 17

What is the function of Lipoprotein Lipase?

Back 17

converts chylomicron triglycerides to free FAs and glycerol

Front 18

What do the products of Lipoprotein Lipase do?

Back 18

Free FAs cross adipocyte membranes into adipose cells. The adipocytes use these FAs (with a new glcerol-3-P derived from adipose glycolysis) to synthesize adipocyte triglycerides. (NOTE: The glycerol goes to the liver)

Front 19

What does Adipose (hormone sensitive) Lipase do in the fasted state?

Back 19

Lipolyzes adipose triglycerides into free FAs and glycerol.

Free FAs: 1.) Leave adipocytes and are bound to albumin for transport in bloodstream, 2.) Enter B-Oxidizing cells, cross into these cells mito and are catabolized there. (NOTE: glycerol goes to the liver)

Front 20

All glycerol from All triglyceride lipolysis, Fed or Fasted, goes where?

Back 20

The Liver

Front 21

Why can glycerol be re-phosphorylated into glycerol-3-P ONLY in the liver?

Back 21

Because only the liver has glycerol kinase, which catalyzes the process

Front 22

What are the fates of glycerol-3-P in the liver in the FED state? In the FASTED state?

Back 22

FED:
1.) glycerol-3-P may be catabolized for energy via glycolysis
2.) Glycerol-3-P may be rephosphorylated and used for hepatic triglyceride synthesis.
FASTED:
1.) All glycerol-3-P converted to glucose via gluconeogenesis

Front 23

What controls Pancreatic Lipase activity?

Back 23

The amount of triglyceride ingested

Front 24

What activates Lipoprotein Lipase?

Back 24

Insulin

Front 25

What activates Adipose (hormone sensitive) Lipase?

Back 25

A phosphorylation process by glucagon and also epinephrine (logical, since these triglycerides are needed in a fast or in an emergency)

Front 26

How does B-Ox produce nucleotides?

Back 26

by itself and via the TCA cycle.

Front 27

B-Ox of FA's produces ATP how?

Back 27

Only if linked to the TCA cycle and/or ox. phos.

Front 28

Is B-Ox an aerobic or anaerobic process? why?

Back 28

Aerobic, because the TCA only operates under aerobic conditions.

Front 29

When does B-Ox occur?

Back 29

During a Fast, in all cells Except RBCs and Brain.
During FED OR FASTED states in skeletal muscles. During prolonged exercise in some skeletal muscle

Front 30

Where does B-Ox occur?

Back 30

All mito except Brain mito.

Front 31

How is B-Ox Regulated?

Back 31

At the level of triglyceride lipolysis

Front 32

What are the starting materials of B-Ox?

Back 32

Long Chain FAs (usually even # Carbons) and NAD+, FAD

Front 33

What are the products of B-Ox?

Back 33

Acetyl CoA, NADH, FADH2 (If Odd-chain FA, propionyl CoA)

Front 34

What is the source of FAs for B-Ox?

Back 34

Majority of FAs are produced by adipose (hormone sensitive) lipase action on adipose triglyceride.
In Skeletal: FED: FAs produced by lipoprotein lipase action on chylomicrons or VLDL triglycerides.
FASTED: FAs from adipose

Front 35

How to Long Chain FAs cross the plasma membrane?

Back 35

Via either facilitated transport or Diffusion. They are then activated to fatty acyl CoA molecules (ATP Expended)

Front 36

How do FAs enter the mito?

Back 36

Long chain activated fatty acyl Co-A molecules bind their activated acyl groups to carnitine for transport into the mito. (Once across mito, each acyl group is removed from carnitine and bound to another CoA)

Front 37

What is the difference between even chain fatty acyl and odd chain fatty acyl B-Ox? Unsaturated FAs?

Back 37

They are the same except in the Odd chain B-Ox, one less acetyl CoA is produced and a propionyl CoA is instead produced.
Unsaturated FAs? One less FADH2 is produced for each double bond present.

Front 38

Are FAs a significant source of gluconeogenic carbons?

Back 38

no

Front 39

Whats the difference in B-Ox of medium chain FAs and long chain FAs?

Back 39

Same, except Medium chain FAs go directly to liver from gut to undergo B-Ox there.

Front 40

What is peroxisomal oxidation, and how does it differ from normal B-Ox?

Back 40

utilizes long chain branched chain FAs, or very long chain FAs. Converts them into fatty acyl CoA compounds. Difference = Location where it occurs

Front 41

What is w-Oxidation?

Back 41

Occurs when we start at the other end of the carbon chain - the side opposite the acid. It is a back-up to the B-Ox process. Produces dicarboxylic acids instead of Acetyl CoA. Increases if normal B-Ox is compromised.