Chap 9: Lipid Metabolism Flashcards
Building Block of Fatty Acid
Acetyl CoA
Lipoids
Phospholipids
Glycolipids
Cholesterol
Cholesterol ester
Lipoids are important for
Membrane components
Triglyceride or triacylglycerole are used to
store and supply energy
Lipids have (chain and groups)
hydrocarbon chain and ester group
Lipid composed by
ester of fatty acid (C - O - C)
Lipid Metabolism
Lipolysis
Lipogenesis
Beta Oxidation
Formation of Ketone Bodies
Lipogenesis (Divided into 3 Processes)
Biosynthesis of glycerol
Biosynthesis of Fatty Acids
Biosynthesis of the Triacylglycerol
Lipogenesis occurs in
(Mostly) adipose tissue, liver, lactating mammary glands, brain
Lipogenesis occurs in
(Mostly) adipose tissue, liver, lactating mammary glands, brain
7 malonyl-CoA (Part 1 of Bio. Tria)
7 Acetyl-CoA + 7CO2 + 7ATP
Acetyl-CoA + 7 malonyl CoA (+ 7ATP) (Part 2 of Bio Tria)
Palmitic Acid
The synthesis of long-chain FA carried out by my 2 enzyme system present in cytoplasm of cell
Acetyl CoA carboxylase
FA synthase complex
One glucose produces
Each acetyl CoA contains
4 glucose molecules
2 Acetyl CoA
2 Carbon
are required to produce 16 carbons of palmitic acid
- Dehydrogenation
loss of hydrogen to form a C=C double bond
- Hydration
the addition of water across the C=C double bond
- Oxidation
loss of electrons and the formation of ketone C=O
- Thiolysis (breaks sulfur)
the splitting of coenzyme-A activated fatty acids
Adipose cells are specialized for
synthesis and storage of triacylglycerol
The TG stored in the adipocytes are hydrolyzed by lipases to produce free FA and glycerol which are released to the blood
Fat mobilization
Hormone-sensitive lipase (HSL)
TG lipase is the rate-limiting enzyme in the TG degradation in adipose tissue
Lipolytic Hormones
- Epinephrine
- Norepinephrine
- Adrenocorticotropic Hormone (ACTH)
- Thyroid-stimulating Hormone (TSH)
Glucagon *
Lipolytic Hormones
- Epinephrine
- Norepinephrine
- Adrenocorticotropic Hormone (ACTH)
- Thyroid-stimulating Hormone (TSH)
Glucagon*
Anti-lipolytic hormone
(Against fat breakdown)
Insulin (Opposite to Glucagon)
(Stores fat)
Beta-Oxidation is a process
by which fatty acids, specifically saturated fatty acids are broken down for use in energy production
(In cases of starvation, intense exercise, or stress)
Beta-oxidation (players)
- Often takes place inside the mitochondrial matrix
- can also occur in organelles called peroxisomes
- Major players : saturated FA and coenzyme (CoA)
- Molecules of water, ATP, FAD+, and NAD+
4 Steps of Beta-oxidation
- Dehydrogenation
- Hydration
- Dehydrogenation of the Beta-hydroxyl group to a ketone
- Acylation
1 of 4 Dehydrogenation of
fatty acyl-CoA to make a trans double bond between alpha and beta carbon
2 of 4 Hydration of
the double bond
3 of 4 Dehydrogenation of the beta-hydroxyl group to a ketone
-e (electrons) removed transferred to NAD+
4 of 4 Acylation
addition of CoA and production of acetyl-CoA
Other Oxidation of Fatty Acids
- Oxidation of Unsaturated Fatty Acids
- Peroximal Fatty Acid Oxidation (VLCFA)
- Oxidation of Propionyl-CoA
Ketogenesis:
Location -
Material -
Rate-limiting Enzyme -
Location - hepatic mitochondria
Materials - Acetyl CoA
Rate-limiting Enzyme - HMG-CoA synthase
Ketones bodies replace
glucose as the major source of energy for many tissues
The liver increases the production of ketone bodies from
Acetyl-CoA generated from fatty acid oxidation
The liver increases the production of ketone bodies from
Acetyl-CoA generated from fatty acid oxidation
Acetyl CoA is the link between
lipid and carbohydrate metabolism pathways
Glucose, glycerol and fatty acids all degrade into
Acetyl CoA
Biosynthesis of FA, ketone bodies & cholesterol all use
Acetyl CoA
