Lipids

Question 1

Explain TAG metabolism during fasting.

Answer 1

-Glycerol backbone brought to liver for gluconeogenesis.
-Fatty acids (FA) brought to liver to form ketone bodies.
-FA brought to muscle for beta oxidation to produce acetyl-CoA. Ketones are also brought to liver to undergo B-oxidation in the mitochondria.

Question 2

What accompanies/encourages lipolysis?

Answer 2

• Fasted state
  -Thyroid Hormones
• EPI, NEPI
• Caffiene, theophylline
• Cortisol
  -Growth Hormone

Question 3

What decreases lipolysis?

Answer 3

• Fasted state
• Insulin
• < Phosphodiesterase activity (insulin)
• Nicotinic acid (niacin)
• Beta Blockers

Question 4

Omega-3: 18:3 (Triangle)9,12,15
What do the numbers mean?

Answer 4

• 3= C at first double bond from Omega end.
• 18:3= 18 is total C In TG, 3 is how many double bonds between delta and omega ends.
• 9,12, and 15 are double bond locations from the delta end

Question 5

TAG Digestion overview with enzymes?

Answer 5

Mouth= Lingual lipase; TAG, DAG, FA
Stomach= Gastric lipase; II II II
Small Int= (Phase I) Bile; Emulsification
(Phase II) Pancreatic lipase, Colipase; MAG, FA

Question 6

2-Monoacylglycerol (2-MAG), Glycerol, C#’s, and long chain fatty acids absorbed into enterocyte. What happens next concerning chylomicron activity?

Answer 6

Emulsified by bile salts and formed into micelle. These enter luminal cells of intestine as nascent chylomicrons with the addition of apo-B48.

Question 7

Ketones are made where and oxidized where?

Answer 7

Made in the liver and oxidized in the muscle, brain, heart, adipose, kidney, and gut in the Crebs cycle.

Question 8

Ketone Synthesis?

Answer 8

Starts with 2 acetyl CoA and produces D-B- hydroxybutyrate and acetone.

Question 9

Lipogenesis explain. What is the enzymatic control here.

Answer 9

Glucose enters glycolysis the liver. Glycerol-3 phosphate forms the backbone the lipid. Pyruvate-enters mitochondrion matrix where it forms citrate and acetyl CoA. Acetyl-CoA goes to form fatty acids and/or cholesterol.

Acetyl-CoA carboxylase is phosphorylated/ activated by insulin and citrate. This enzyme catalyzes the reaction of acetyl-CoA that forms Malonyl CoA. On the other hand, glucagon (low energy) inactivates ACC as well as palmitoyl CoA.

Glucose - Citrate - Acetyl-CoA - Malonyl CoA - Palmitate - Palmityl CoA

Question 10

LDL receptor recognizes

Answer 10

ApoB100 & apoE, binds LDL, IDL, VLDL, & chylomicron remnants

Question 11

Where and how do chylomicrons mature?

Answer 11

In the blood HDL gives nascent chylomicrons ApoCII and ApoE which matures the chylomicron.

Question 12

HDL functions?

Answer 12

-Transfer Pro
-Picks up TG and PL from lipoproteins
- picks up cholesterol from membranes
-converts cholesterol to cholesterol esters via LCAT and CETP

Question 13

What is atherogenesis?

Answer 13

Production of foam cells by phagocytosis of oxidized LDL. (Macrophage to foam cell)

Question 14

What is an eicosanoid?

Answer 14

Regulators of cell fx:
- Prostoglandins, thromboxanes, and leukocytes
- Inflammatory response to destroy orgs and repair tissue (pain swell fever)
- Muscle contraction
-Na and H20 balance, BP
- Bronchoconstriction and dilation

Question 15

Omega-6 vs. Omega-3 FAs

Answer 15

They are polyunsaturated fatty acids.

Omega-6:
Vegetable and safflower oils; meat, poultry, and eggs
-Linoleic (LA)
-y-linolenic (GLA)
-DGLA
-Arachidonic

Omega-3:
Green leafy vegetables, flax/chia seeds; canola, walnut, soybean, krill, and algae oils; fatty fish
- ALA
-SDA
-ETA?
-EPA
-DPA
-DHA

Question 16

Functions of Eicosanoids (w6 and w3)

Answer 16

w6 (Pro-inflammatory) increases…
- Platelet and blood clotting
-Vasoconstriction
-Immunity
-Inflammation

w3 (Anti-inflammatory) decreases…
-Vasoconstriction bc it dilates vessels
-Blood clotting
- Inflammation