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where does transamination occur:
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liver
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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.
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glucagon and insulin are both released from the ___.
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pancreas
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maintenance of blood glucose is the exclusive function of the ___.
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liver
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Both lipolysis and lipogenesis start with ___ ___.
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acetyl coA
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chain growth of fatty acids proceeds by additions of 2 carbon unit derived from malonyl coA.
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3 major ketone bodies:
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- acetoacetate- beta- hydroxybutytrate- acetone
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what enzyme converts pyruvate to acetyl coA?
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- pyruvate dehydrogenase
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muscle glycogen is used during exercise for ___ production. muscles lack what enzyme that prevent them from contributing to blood glucose.
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- ATP- glucose-6-phosphatase
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what is the building block of lipogenesis?
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- citrate
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Alanine cycle:
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- 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
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Glucagon encourages what processes:
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- gluconeogenesis- adipose tissue lipolysis- glycogenolysis- catabolic pathways
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nutrient pool contents:
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- amino acids- lipids- simple sugars
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what tissues use ketone bodies efficiently?
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- muscle- heart
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Human body does not want to do gluconeogenesis and glycolysis at the same time, thats why we have alternating levels of insulin and glucagon.
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In gluconeogenesis ____ __ ____ is responsible for converting glucose-6-phosphate into glucose. This only happens in the liver.
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- glucose-6-phosphatase
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If citrate is generated b/c lots of acetyl coA, then ____ is occuring.
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lipogenesis
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fasted state events:
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- 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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___ ___ encourages storage of carbohydrates as fat by dephoshporylating and thus activating acetyl coA carboxylase.
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- protein phophatase
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In glycolysis, fructose-6-phosphate is converted to fructose-1,6-bisphosphate via ____. This is the rate limiting step in glycolysis. This enzyme is activated by ___ and inhibited by ___.
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- Phosphofructokinase (PFK)- activated by insulin- inhibited by glucagon
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Glycerol can be used for gluconeogenesis by being converted to ___ ___ ___ by ___ ___.
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- glyceraldehyde-3-phosphate- glycerol kinase
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when a triglyceride is broken down, what bonds are broken?
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- ester bonds
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Beta oxidation happens in the ___. Lipogenesis happens in the ___.
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- mitochondria- cytoplasm
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Citrate cycle:
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- 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
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post-absorptive phase aka fasted state:
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release of stored fuel for energy
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In a short term fasted state (3-4 hours after a meal), the body relies on ___ and ___ to produce blood glucose.
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- glycogen- glycogenolysis
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What enzyme is unique to the liver and allows it to directly contribute to blood glucose?
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- glucose-6-phosphatase
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amino acids can be classified as ___ or ___.
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- glycogenic- ketogenic
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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.
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- citrate
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Fatty acid synthesis (acetyl coA> malonyl coA) is a ____ reaction.
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- carboxylase reaction(acetyl coA carboxylase makes malonyl coA from acetyl coA)
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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 __ __.
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- glycerolipids- sphingolipids- Carnitine acyl-transferase- beta-oxidation- acetyl coA
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citrate, protein phosphatase, and acetyl coA carboxylase are the rate limiting steps in fatty acid synthesis, explain.
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- 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
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summary of fatty acid metabolism :
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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
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glycolysis and TCA cycle use ___ ___ ___ to produce ATP. The electron transport chain uses ____ ___ to make ATP.
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- substrate level phosphorylation- oxidative phosphorylation
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Short Term Regulation of fatty acid synthesis via acetyl coA carboxylase:
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- citrate: allosteric activator- long chain acyl coAs: allosteric inhibition- insulin: enhancement- dephosphorylation: enhancement- glucagon: inhibition- phosphorylation (cAMP): inhibition
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Long term regulation of acetyl coA carboxylase for fatty acid synthesis:
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- 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
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In a fasted state, ___ ___ ___ is phosphorylated, and thus activated, to break down triglycerides into 3 free fatty acids and glycerol.
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- hormone sensitive lipase
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In synthesizing glycogen from glucose, what enzyme is key?
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- glycogen synthase is key in adding glucose-1-phosphate to growing glycogen chain
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In a long term fasted state your body relies on ___ to break down amino acids to raise blood glucose.
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- gluconeogenesis via oxaloacetateside note: muscle tries to conserve glycogen content for fight or flight
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60-70% of our energy output is our ___ ___ ___. 25-30% of our energy output is ___.
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- resting metabolic rate- movement
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Once exercise is over, lactate can go to the ___ and be converted to ___ and then be used to make ___ via the ___ __ in the __.
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- liver- pyruvate- glucose- Cori cycle- liver
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what is the only amino acid that is purely ketogenic?
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- leucine- leucine can make acetyl coA
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