Lipid Metabolism Part II Lipoprotein Metabolism Flashcards
what is mean by postabsorptive state?
means fatty acids can be released from adipose tissue to be used for energy.
The fall in insulin activates a ____________ that hydrolyzes triglycerides, yielding ______________.
hormone-sensitive triacylglycerol lipase (HSL) ,
fatty acids and glycerol.
Epinephrine and cortisol. also _____________.
activate HSL .
Free fatty acids are transported through the blood in association with___________
serum albumin.
what will be picked up by liver and converted to what for gluconeogenesis?
Glycerol may be picked by liver, converted to dihydroxyacetone phosphate (DHAP)
fatty acids are oxidized into tissues including what and by which pathway?
liver, muscle, and adipose tissue, by β-oxidation pathway.
What can NOT use fatty acids and so continue to rely on glucose during what time?
Erythrocytes and brain, during normal periods of fasting.
Erythrocytes lack ____________, and fatty acids do not cross the______________ efficiently.
mitochondria, blood–brain barrier.
what all diffuse freely into mitochondria to be oxidized.
short-chain fatty acids and medium-chain fatty acids.
long-chain fatty acids must be ____________& transported into the mitochondrion by a _______________ to be oxidized.
activated, carnitine shuttle
very long-chain fatty acids enter _______________
via an unknown mechanism for oxidation.
enter peroxisomes
_____________on the outer mitochondrial membrane, activates the fatty acids by attaching CoA.
Fatty acyl-CoA synthetase
The fatty acyl portion is then transferred onto carnitine by _________________for transport into the mitochondria.
carnitine acyltransferase-1 (CAT-1).
what is shuttled across the inner membrane.
Fatty acylcarnitine
Carnitine acyltransferase-2 (CAT-2)/ carnitine palmitoyl transferase-2 (CPT-2) transfers the ______________ back to ___________.
fatty acyl group, a CoA .
Carnitine acyltransferase-1 is inhibited by _____________.
malonyl-CoA .
Carnitine acyltransferase-1 prevents newly synthesized fatty acids from entering the ______________.
mitochondria.
Insulin indirectly inhibits β-oxidation by activating ____________ and increasing the ____________ concentration in the cytoplasm which inhibits_____________.
acetyl-CoA carboxylase, malonyl-CoA, Carnitine acyltransferase.
Carnitine acyltransferase-1 and -2 (CAT-1 and CAT-2) are also called as?
carnitine palmitoyl transferase-1 and -2 (CPT-1 and CPT-2).
what reverses the process of fatty acid synthesis by oxidizing?
β-oxidation.
β-oxidation after oxidizing it releases units of _______________ and what is the pathway of it?
acetyl-CoA, repetition of 4 steps.
Each 4-step cycle releases one _________and reduces NAD and FAD producing___________.
acetyl-CoA, NADH and FADH2
FADH2 and NADH are oxidized in the __________ providing ATP.
electron transport chain.
what cycle does muscle and adipose tissue, the acetyl-CoA enters to?
citric acid cycle.
in liver ATP used for what?
Gluconeogenesis.
By activating what does acetyl-CoA stimulates gluconeogenesis?
Pyruvate carboxylase.
In a ___________ state, the liver produces more acetyl-CoA from β-oxidation than is used in the citric acid cycle
fasting state
the acetyl-CoA is used to synthesize __________ that are released into the blood for other tissues.
ketone bodies.
What are the two most common genetic deficiencies affecting fatty acids oxidation ?
1.Medium chain acyl-CoA dehydrogenase (MCAD) deficiency. (it’s in liver.)
2.Myopathic carnitine acyltransferase (CAT/CPT) deficiency. (it’s in muscle.)
In MCAD______________ should be strongly associated with a block in hepatic β-oxidation.
Non-ketortic hypoglycemia .
In MCAD______________ should be strongly associated with a block in hepatic β-oxidation.
Non-ketortic hypoglycemia.
At what period hypoglycemia can become profound due to lack of ATP to support gluconeogenesis.
During fasting.
