Lecture 15 - Triacylglycerol Formation Flashcards
Most lipids stored in the body are….
triglycerides
what is a very important precursor for forming lipids?
phosphatidic acid
what are 3 important uses for cholesterol?
- Essential component of the plasma membrane
- Precursor to steroid hormones
- Intermediates in the cholesterol metabolism pathway are precursors to other cellular products (Ubiquinone)
Cholesterol metabolism requires…..
cytosolic acetyl-coA
3 acetyl-coA molecules join to form….
HMG-CoA
What is the rate-controlling enzyme in cholesterol metabolism?
HMG-CoA reductase
HMG-CoA reductase is a drug target for….
cholesterol-lowering drugs (the statins)
cholesterol can be _____ and packed into ____ particles
cholesterol can be ESTERIFIED and packaged into LIPOPROTEIN particles
what are eicosanoids?
a large class of relatively short-lived molecules
(type of lipid_
Eicosanoids are derived from…
fatty acid arachidonate
What are some effects of Eicosanoids?
stimulate smooth muscle contraction which causes pain and clotting
a pain killer would block the conversion of ___ to ____
arachidonate to an eicosanoid
sphingolipids are utilized where in the body?
the nervous system
Sphingolipids use _____ rather than ____ as a backbone
use serine rather than glycerol as a backbone
What are some functions of sphingolipids?
cell growth
cell migration
regulation of apoptosis
Give an example of a disease associated with sphingolipids?
Neiman-Pick
unable to degrade sphingolipids
In the FED state, dietary lipid is…..
packaged in lipoprotein chylomicron (ultimately stored in fat cells)
in the FED state, carbohydrates are stored as….
glycogen until max glycogen is formed - then carbohydrates are stored as fat
what is the major hormone involved while in the fed state?
insulin
what does insulin do while in the fed state?
stimulates fatty acid synthesis of liver and fat cells. Favors triglyceride formation
In the fasted state, what is produced — fatty acids or triglyceride?
fatty acids are produced by the breakdown of triglycerides in fat cells
what hormone stimulates the breakdown of triglyceride to fatty acids?
epinephrine
In the fasted state, the liver takes up….
fatty acids
in the fasted state, the liver takes up fatty acids and does what with them?
oxidizes them to carbon dioxide or partially oxidizes them to ketone bodies
What is the role of fat cells?
synthesize, store, and release fat
What is the role of muscle cells?
utilize fat and ketone bodies
What is the role of the liver?
(4 things)
fat synthesis
VLDL secretion
fatty acid oxidation
ketone body synthesis
What is the role of the liver?
(4 things)
fat synthesis
VLDL secretion
fatty acid oxidation
ketone body synthesis
during feeding, what hormone becomes elevated?
insulin
Glycogen is converted to _____
triglycerides converted to _______
glycogen converted to HEXOPHOSPHATE SUGAR
Triglycerides converted to FATTY ACIDS
While fatty acid oxidation and ketone body formation are high, Molonyl-CoA levels are ______
high
Malonyl-coA is a rate determining intermediate in…..
fatty acid synthesis
When malonyl-CoA levels are low, what happens?
-the inhibition of fatty acid oxidation is lifted (so overall increased)
-Increased ketone body formation
in the fasted state, what 2 hormones become elevated?
glucagon and epinephrine
In the fasted state, Malonyl-CoA levels are______
LOW
In the fasted state, epinephrine concentration in the blood is elevated. What does this cause?
Stimulated fat cells to release more fatty acids to the blood
stimulates the liver to produce ketone bodies
What body part primarily uses glucose?
the brain
Gluconeogenesis becomes critical in the ___ state
fasted
If starvation continues, what will be broken down?
amino acids (not preferred)
During exercise, what can you say about blood flow?
blood flow is shunted away from most tissues except for the MUSCLES and the BRAIN
Name 3 things that occur biochemically during anaerobic exercise
-Muscle breaks down its glycogen stores
-glycogen phosphorylase is activated (causes glycogen to breakdown quicker)
-NO EFFECT ON LIPID METABOLISM
The anaerobic state involves what kind of exercise?
intense exercise. Quick, small amounts of ATP are produced
Name 3 things that happen biochemically during AEROBIC exercise
-increased epinephrine leads to fat cells releasing fatty acids
-fatty acids are then oxidized by muscle cells
-Malonyl-CoA concentration is lowered by AMP kinase activity and increased AMP concentration
Which is more severe — Type 1 or Type 2 diabetes
type 1 is more severe
explain why type 1 diabetes develops
pancreatic beta cells are impaired. Causes insufficient release of insulin
(ALMOST NO INSULIN PRODUCTION)
Explain type 2 diabetes
type 2 diabetes can lead to abnormally high levels of insulin because the body becomes insensitive to insulin. More insulin is needed to have the same effects
explain 3 things that occur in type 1 diabetes that makes it so severe
-fatty acids are released from fat cells
-Ketone body levels are elevated (which can create strong osmotic pressure_
-Gluconeogenesis is increased
What is the treatment for type 1 diabetes?
Insulin is given
What is the treatment for type 2 diabetes?
metformin is given
-inhibits gluconeogenesis and activates muscle glucose uptake by the stimulation of AMP kinase
What is a good treatment for both Type 1 and Type 2 diabetes?
EXERCISE - most likely to stimulate AMP kinase
