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Phys. Exam 2 Metabolism 2
Metab 2 for phys exam 2
65
Physiology
Graduate
10/14/2010

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Term
ketone bodies can enter into glycolysis or the TCA cycle. Glyercol from fat can enter into glycolysis. Fatty acids can enter into the TCA cycle.
Definition
Term
In gluconeogenesis ____ __ ____ is responsible for converting glucose-6-phosphate into glucose. This only happens in the liver.
Definition
- glucose-6-phosphatase
Term
Glycerol can be used for gluconeogenesis by being converted to ___ ___ ___ by ___ ___.
Definition
- glyceraldehyde-3-phosphate
- glycerol kinase
Term
amino acids and lactate can be used for gluconeogenesis by being converted to ___ in the ___. Then the pyruvate goes into the ___ where it is made into ___ via ___ ___. Then ___ is converted to ___ and carrried back to the cytoplasm, where it is converted back to ____.
Definition
- pyruvate in the cytoplasm
- mitochondria
- oxaloacetate
- pyruvate decarboxylase
- oxaloacetate
- malate
- oxaloacetate
Term
Give an example of transamination:
Definition
alanine + alpha-ketoglutarate = pyruvate+ glutamate
Term
where does transamination occur:
Definition
liver
Term
Transamination produces ___ which combines with CO2 to make ___. This goes into the blood and goes to the ___ where it gets excreted as urine.
Definition
- NH3 (ammonia)
- urea
- kidney
Term
Transamination is also known as ___ ____. The products of transamination are a ___ ___ and an __ ___.
Definition
- oxidative deamination
- keto-acid
- amino acid
- urea
Term
amino acids can be classified as ___ or ___.
Definition
- glycogenic
- ketogenic
Term
List the three amino acids that are glycogenic and ketogenic?
Definition
- tryptophan
- phenylalanine
- tyrosine
Term
what is the only amino acid that is purely ketogenic?
Definition
- leucine
- leucine can make acetyl coA
Term
Once exercise is over, lactate can go to the ___ and be converted to ___ and then be used to make ___ via the ___ __ in the __.
Definition
- liver
- pyruvate
- glucose
- Cori cycle
- liver
Term
enzyme in the liver that converts lactate to pyruvate:
Definition
lactate dehydrogenase
Term
Alanine cycle:
Definition
- pyruvate + glutamate >> (alanine transaminase)>> alpha-ketoglutarate + alanine
- alanine travels to liver and combines with alpha-ketoglutarate and via alanine transaminase reproduces pyruvate
- then the pyruvate can be made into glucose
Term
glucose yields ___ ATP. Palmitate yields ___ ATP.
Definition
- 36-38 ATP
- 129 ATP
Term
summary of fatty acid metabolism :
Definition
triglyceride in adipose tissue >> (lipolysis)>> FFA in blood >>transported to liver and extrahepatic tissues in an SA complex>>in liver and extrahepatic tissues FFA>> acetyl coA for energy or biosynthesis
Term
what predominates in blood in a fasted state?
Definition
- AMP
- phosphodiesterase
- glucagon
Term
In a fasted state, ___ ___ ___ is phosphorylated, and thus activated, to break down triglycerides into 3 free fatty acids and glycerol.
Definition
- hormone sensitive lipase
Term
when a triglyceride is broken down, what bonds are broken?
Definition
- ester bonds
Term
lipolysis is similar to blood coagulation b/c both have cascade of events. List these events:
Definition
- hormone receptor interaction>active adenylate cyclase> ATP gets converted to cAMP > active protein kinase> active protein kinase activates triacylglycerol lipase> triacylglcyerol lipase breaks down triglycerides
Term
The release of each fatty acid in lipolysis causes acceleration of the process
Definition
Term
In lipolysis, only the removal of the first fatty acid is hormonally regulated.
Definition
Term
Human body does not want to do gluconeogenesis and glycolysis at the same time, thats why we have alternating levels of insulin and glucagon.
Definition
Term
In the liver, acyl-coA in the cytoplasm can be made into ____ and ___. ___ ___ has to move acyl coA into the mitochondria from the cytoplasm. Once acyl coA is in the mitochondria in liver, __ ___ converts it to __ __.
Definition
- glycerolipids
- sphingolipids
- Carnitine acyl-transferase
- beta-oxidation
- acetyl coA
Term
Acetyl-coA produced by beta oxidation in the liver can be used for what?
Definition
- TCA cycle and yield energy and CO2
- ketogenesis to make ketone bodies
Term
Ketone bodies are only made in the ___. Ironically though, ketone bodies cannot be used by the __.
Definition
- liver
- liver

KETONE BODIES ARE MADE IN THE LIVER, BUT CANNOT BE USED BY THE LIVER.
Term
major pathways using acetyl coA are the ___ __ and ___ ___ ___. Fatty acid synthesis is preferred in the __ state and happens in the ___.
Definition
- TCA cycle
- fatty acid synthesis
- fed
- cytosol
Term
In the fasted state when acetyl coA accumulates in the ___, it is converted to ___ ___ by ___, an overflow pathway.
Definition
- mitochondria
- ketone bodies
- ketogenesis
Term
3 major ketone bodies:
Definition
- acetoacetate
- beta- hydroxybutytrate
- acetone
Term
what tissues use ketone bodies efficiently?
Definition
- muscle
- heart
Term
Ketone body oxidation happen in ___ tissues. List order.
Definition
- extrahepatic tissues

3-hydroxybutyrate>>acetoacetate>>acetyl-coA
Term
fatty acids are oxidized for energy via beta oxidation to produce acetyl coA. If too much acetyl coA builds up, ketone bodies will be made.
Definition
Term
insulin is very important in slowing down ____. But in diabetics, ___ is always going on b/c no insulin.
Definition
- lipolyis
- lipolysis
Term
3 Mechanisms of Regulation of Fatty Acid Metabolism:
Definition
1. availability of fatty acids from triglyceride lypolisis
2. transport of fatty acyl coA into mitochondria
3. availability of coenzymes (NAD and FAD) to promote beta oxidation.
Term
alcohol uses up conezyme A and prevent beta oxidation.
Definition
Term
where does pyruvate get converted to acetyl coA?
Definition
- mitochondria
Term
what is the building block of lipogenesis?
Definition
- citrate
Term
Beta oxidation happens in the ___. Lipogenesis happens in the ___.
Definition
- mitochondria
- cytoplasm
Term
Because most of the acetyl coA is made in the mitochondria, it has to be transported to the cytosol in the form of ___ in order to be used for fatty acid synthesis.
Definition
- citrate
Term
If citrate is generated b/c lots of acetyl coA, then ____ is occuring.
Definition
lipogenesis
Term
Both lipolysis and lipogenesis start with ___ ___.
Definition
acetyl coA
Term
So if your breaking down fat and acetyl coA builds up, ___ will occur. But if you just ate a lot and there is a lot of acetyl co A then ____ will occur.
Definition
- ketogenesis
- lipogenesis
Term
Citrate cycle:
Definition
- acts to bring acetyl coA into cytoplasm for lipogenesis

- oxaloacetate + acetyl coA>> citrate>> citrate goes from mitochondria to cytosol>> citrate breaks into acetyl coA and oxaloacetate
Term
coenzymes needed for lipolysis/beta oxidation:
Definition
- NAD
- FAD
Term
Fatty acid synthesis (acetyl coA> malonyl coA) is a ____ reaction.
Definition
- carboxylase reaction
(acetyl coA carboxylase makes malonyl coA from acetyl coA)
Term
what is the rate limiting step of fatty acid synthesis?
Definition
- formation of malonyl coA via acetyl coA carboxylase
Term
chain growth of fatty acids proceeds by additions of 2 carbon unit derived from malonyl coA.
Definition
Term
citrate, protein phosphatase, and acetyl coA carboxylase are the rate limiting steps in fatty acid synthesis, explain.
Definition
- citrate bring acetyl coA into cytoplasm causes activation of acetyl coA carboxylase, thus they are both rate limiting
- protein phosphatase also activates aceetyl coA carboxylase be dephosphorylatioin
Term
what are the regulators of fatty acid synthesis?
Definition
- citrate
- protein phosphatase
- acetyl coA carboxylase
Term
___ ___ encourages storage of carbohydrates as fat by dephoshporylating and thus activating acetyl coA carboxylase.
Definition
- protein phophatase
Term
___ ___ ___ ___ inactivates acetyl coA carboxylase. ,this can be signaled by __ and ___ so that storage of fat is stopped. This inactivation uses ___.
Definition
- cAMP dependent protein kinase
- glucagon
- epinephrine
- ATP
Term
nutrient pool contents:
Definition
- amino acids
- lipids
- simple sugars
Term
Glucagon encourages what processes:
Definition
- gluconeogenesis
- adipose tissue lipolysis
- glycogenolysis
- catabolic pathways
Term
Insulin encourages what pathways?
Definition
- glycolysis
- glycogen synthesis
- lipogenesis
- Biosynthetic anabolic pathways
Term
Glycogenolysis happens in the muscle and liver, but only the liver can contribute to blood glucose. Glycogenolysis in the liver can maintain blood glucose for the first two hours of the fasted state to prevent reliance on amino acids.
Definition
Term
muscle glycogen is used for fight or flight.
Definition
Term
Short Term Regulation of fatty acid synthesis via acetyl coA carboxylase:
Definition
- citrate: allosteric activator
- long chain acyl coAs: allosteric inhibition
- insulin: enhancement
- dephosphorylation: enhancement
- glucagon: inhibition
- phosphorylation (cAMP): inhibition
Term
what is an allosteric inhibitor of fatty acid synthesis:
Definition
- long chain acyl coAs
Term
would phosphorylation enhance or inhibit fatty acid synthesis?
Definition
- inhibit

DEPHOSPHORYLATION ENHANCES FATTY ACID SYNTHESIS.
Term
Long term regulation of acetyl coA carboxylase for fatty acid synthesis:
Definition
- high carbohydrate diet: enhanced enzyme synthesis, increase FA synthesis
- low fat diet: enhanced enzyme synthesis, increased FA synthesis
- high fat diet: decreased enzyme synthesis
- fasting: decreased enzyme synthesis
- glucagon: decreased enzyme synthesis
Term
GLUT 2 transporters are found where?
GLUT 1 transporters are found where?
Definition
- GLUT-2: liver
- GLUT-1: blood vessels
Term
what is the rate limiting step with beta oxidation?
Definition
- CPTI: carnitine palmityl transferase: brings fatty acid and carnitine into mitochondria for beta oxidation
- CPTI is inhibited by malonyl coA
Term
what inhibits the rate limiting step of beta oxidation and why is this important?
Definition
- malonyl coA inhibits CPTI of beta oxidation
- this is significant b/c malonyl coA is an intermediate unique to fatty acid synthesis
- thus malonyl coA prevents oxidation and synthesis from happening at the same time
Term
Insulin actions:
Definition
- increased facilitated diffusion of glucose into tissue cells
- enhances glucose conversion to fat and glycogen
- inhibits lipolysis
Term
fasted state events:
Definition
- decreased blood glucose and increased amino acids> alpha cells of pancreas> glucagon> stimulates glycogenolysis and gluconeogenesis in liver and stimulates lipolysis (fat breakdown)> increased levels of glucose and insulin in plasma, increased levels of fatty acids in plasma, fat used by tissue cells which further increases blood glucose> increased blood glucose inhibits alpha cells of pancreas
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