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165 Cards in this Set
- Front
- Back
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Are glycolsis and gluconeogenesis co-regulated?
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YES, AMP
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How does AMP affect glycolsis versus gluconeogensis
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AMP--need ATP--favors glycolsis
AMP inhitibs gluconeogensis-requires energy |
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Do Amino Acids only furisnh 10-15% of our total energy needs
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YES
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3 Reasons we break down Amino acids
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1. Turnover of body protein
2. Excess amino acid ingestion 2. Fasting or Diabetic Mellutis |
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What does amino acids break down into
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Lose NH4+ amino, and form alpha keto acids
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Can you store amino acids
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NO--thats why we break them down when we have excess
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Where does aplha keto acids then go?
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Actyl-CoA and feed into citirc acid cycle
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Where does NH4+ go? It cannot be free!!
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Glutamate and Glutamine Collect NH4+
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Most amino acids in the LIVEr the amino group is transfered to what
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alpha ketoglutarate to form glutamate
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In skeletal muscle where are excess amino groups transferred
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to pyruvate to form alanine
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3 excretory forms of Nitrogen
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1. Ammonia, Urea, and Uric Acid
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Where are dietary protiens ezymatically degreated to amino acids
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in the stomach and intestine
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Where are most amino acids metabolized
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in the liver
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Whers are free amino acids transported through and enter
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the villi, and enter the capillaries and transfer to liver
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The 1st step in catabolism of amino acids in the liver is
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removal of the alpha amino groups by transaminases
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What is transamination reaction
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amino group transfer to alpha-ketoglutarate releasing a alpha keto acid, and forming glutamate
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What serves as a colletor of amino groups
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alpha keto-glutarate
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What serve as a carrier of NH4+ in the cell
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glutamate
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What aagain are transaminases or aminotranferases
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enzyme that catazles the transfer of the amine group
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Are Aminoranferases are specific for individual amino acids? So so alanine aminotransferase and lecuine aminotranferases exist
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YES
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All aminotranferase have the same prostetic group what is it?
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pyridoxal phosphate (PLP)--Vitamin B6
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Are aminotranferases an assay for tissue damage--especially in heart and liver
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YES
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Glutamate carries NH4+ from the cytosol to
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the mitochondria
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What happens do Glutamate in the mitochondria
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undergoes oxidative deamination
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The alpha ketoglutarate formed glutamate deamination is used
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in citric acid cucle for
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What do Serine and threoine undergo, and then enter
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Direct oxidative deamination--enter Citrica Acid Cycle
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What does serine b/come from direct oxidative deamiantion
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pyruvate adn NH4
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What was Threoine become from direct oxidative deamination
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alpha ketobutyrate + NH4
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Ammonia is quite toxic, and in many tissue some process generate free ammonia, much of the free ammonia is converted to a non-toxic in the tissue before entering blood, for this to occur
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the free amino group procuded in tissues is combined with glutamate to yield glutamine
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Glutamine Transports Ammonia in the BLOOD TO the liver, what does Glutamate do
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carries Ammonia IN the LIVER
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The formation of Glutamine requires
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ATP
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Benift of glutamine having no net charge
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easily pass out of cell into blood, and into liver mitrochondria matrix
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Once Glutamine in liver, it relases NH4--and forms
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GLutamate--which still contain one amino group
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In the liver, the ammonia from all sources is disposed of by
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urea
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In active skeletal muscle excess NH3+ bind and form
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pyruvate a readily available product of muscle glycolsis forming alanine
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What does alanine do
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transports ammonia from skeletal muscle to liver
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2 Fates of Alanine in the liver
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alanine aminotranferase tranfer amino group to alpha ketoglutarate to form PYRUVATE and GLUTAMATE
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What happens to Glutamate
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Enters the mitochonrdia undergoes deamineation, releases NH4+ to urea
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What is fate of pyruvate in the liver
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pyruvate undergoes gluconeogeneis in liver to form more glucose, that replensish lost glucose in skeletal muscle
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Why is gluconeogensis of pyruvate occur in the liver, instead of doing in muscle
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b/c gluconeogenesis cost ATP, want to save all ATP in muscle as possible, b/c excess pyruvate means--muslcles are usally acting with oxygen
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Vigrous acting skeletal muscles produce lots of
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pyruvate and lactate
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What is fate of lactate
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is carried to liver wehre it is converted to glucose, also converions of lactate does produce 2 ATP
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What is the glucose-alanine cycle
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Amino acid is donated to pyruvate forming alanine, whihc enter blood, and enter liver, once enters liver amino group transfer to alpha-keto glutarate forms pyruvate and glutamate
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Ammonia is very toxic, speculation for toxiticty is still unknown, but most explanation revolve around depletion
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ATP , and glutamate, and NADH
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Where does urea production almost exclusively occur
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in the liver
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After urea is formed where does it goes
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into the bloodsteam, adn thus to kidney, and excreted into urine
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Where does the urea cycle occur
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both the mitochondria and cytosol
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After NH4+ is generated from its removal from glutamate what happens
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its forms Carbamoyl phosphate by carbamoyl phophate synthase
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Does formation of Carbamoyl phosphate synthetase require lots of ATP
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YES--2 ATP
1st ATP for condenstaion reaction 2nd phosphate donor |
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What are 4 other enzymes that particpate in urea cycle
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Orithine transcarbamolase, argininosuccinate synthase, argininosuccinase, arginase
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What are 2 components that are transported acros the mitochondrial membrane by specific transport systems
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Ornithine, and cirulline
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1st step of how Carbamoyl phosphate formed
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NH4+ picks of HC03 from respiraation,
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How is Cirtuline formed
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Carabmoyl donates is carbamoyl group to Orthinine to form Citrulline (releasing Pi)
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What ezyme catalzyes Citulline formation
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ornithine transcarbamoylase
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How do you form Argininosuccinate
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addition of aspartate to citrulline--uses 1 ATP
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How many amino groups does argininosuccinate have and orgin
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2 amino groups 1 from glutmate, and one from aspartate
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How do form Arginine
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Arininosucinase break in arginine and fumarate
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Arginine has how many amino groups and orgin
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gluatame and aspartate
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Where does fumerate go
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enters the mitochondria and undergoes CAC
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What is last step of cycle
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arginase breaks molecule and forms urea and ornithine
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The urea cycle is regulated at 2 levels
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1. Starvation and protein-rich diets
2. Carbamoyl phosphate |
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How does starvation and protein rich diets regulate the urea cycle
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urea increases when you eat lots of protein (need break down), generating lots of aminos
also starvation--muclse protein breakdown occurs (more amino groups) |
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How is the urea cycle regualted by carbamoyl phosphate synthetase
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allosterically regulated by N-acetylglutamate
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How is N-acetylgulatamte synthesized
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from acetyl-CoA and glutamate
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What do icnrease glutamate concentrations serve as
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a signal to stimulate the urea cycle though carbamoyl phophate synthase
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Does carbamoyl phosphate also catalyzes a COMMITTED step with respect to ATP utilization
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YES
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What is the Krebs Bicycle
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link between the CAC and Urea Cycle
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Why cannot humans live on protein free diet
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essential amino acids--cannot be MADE--must be provided in diet
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If you cannot breakdown amino acids does it lead to serious effects
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YES, mental retardartion, death
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Biologoical lipids are a chemically diverse group that share a common feature
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insolubility in water
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3 Diverse Funtions of Lipids
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1.Fats and oils are stored forms of energy
2. Major strcutral elemts of membrane 3. Present in small quanties play crucial roles in hormore precuros, and other |
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Fats and oils are derviates of..
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fatty acidy
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Fatty acids are derivates of
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HIGHLY redcued hydrocarbons
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What is chemical structure of fatty acids
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Are carboxcyllic acids, with hydrocarbon chains
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What is differance between fully staturated, and unsaturated
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fully saturated-with Hydrogens (no double bonds)
unsaturated--has double bonds |
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Why are unsaturated fatty acids liquids?
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unsaturated has kinks--so Van der Whals forces---are what make a lipid solid--kinks makes lipids farther apart--then less Wan Der Whals forces--so liquid
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Where does Omega 3-Fatty acids come from in terms of nonmenclature
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W-Omega is last carbon--3 carbons away from last carbon is where double bond is
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What are the ESSENTIAL POLYUNSATURATED fatty acids in Omega-3-fatty acids
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alpha-linolenic acid, iecosapentenioc acid, and docosahexanoic acid
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What type of emega fatty acid is vegetable/plant oils
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Omega-6-fatty acids
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What are Triacylglycerols
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Fatty acids Esters of Glycerol
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What are the simplest lipids, and why
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Triacylglycerols--same as triglercides--contains a glycerol backbone--with 3 fatty acids
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Triglycerols have lower specific gravity THAN WATER--which means
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explains why oil floats on top of water
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What happens to triglycerides in the well-fed state,
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the body will store TG's in the adipose tissue--as lipid droplets
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What happens to triglycerides during fasting
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Lipases in adipocytes hydrolysis the TG's releasing fatty acids for export to
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2 signifigant advantages to using TG's as stored fuels
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1. TG's yield twice the amount of energy
2. Fat stores can supply energy for weeks to months--where all glycogen is used up in a day |
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Are TG's a source of energy for fasting/starvation and hibernation, and bouancy in sea mammals
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YES
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Membranes are amphipathic, which is
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one end of the molecule is hydrophobic, other ends is hydrophilic
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How are membrane bilayers formed?
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Hydrophobic interactions with each other, adn hydrophilic interactions with water
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What is the most simple hydrophilic component in membranes
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OH
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Why doesnt water like order?
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PROBABILITY---there is only one way to be ordered--lots of ways to be disordered
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Why do memebranes only have 2 hydrocarbons?
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3rd part of membrane lipids is a hydrophilic part
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What are the 3 general types of membrane lipids
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1. Glycerophospholipids
2. Sphingolipids 3. Sterols |
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What are glycerophopholipids
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2 fattys acids ester linked to first 2 carbons of glycerol, and a highly polar groups attached by a phosphodiester linkage to 3rd carbon
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What is the parent compound of Glycerophospholipids
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Phosphatidic acid
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What are spingolipids
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Contains 1 fatty acid and a spingosine, and one polar tail
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What is parent compound of spingolipids
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ceraminde
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Sphinogolipids can be subdivied into
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Phospho or glyco sphingolipids
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What are Glycosphingolipids are often, and contain complex
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sites of biological regonitions--oligosaccharides
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What do carbohydrates moieties on glycosphinoglipds define
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3 human blood gropus
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Most cells continually degrage and replace membranes-How are Phopholipids and sphingolipids degraded
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by lysosomes
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Structure of Sterols
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4 fused rings (3 six-membrane rings, and 1 5 membered ring) with 1 OH--makes rigid
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What is the major sterol in aminal tissue
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cholesterol
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Sterols are both
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precurser molecule for hormones, and bile acids, and structual lipid of membranes
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What are steriods )testosterone, estradiol, cortsol, prednisone) derived from
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cholesterol
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What is Tay-Sachs disease an example of
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strutural lipids are constanly degraded by lysozymes, (dont exist)so Gangloslides accumlate and buildup leads to retardation
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Where do digestiosn and absopriton of dietary lipids occur?
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small intestine, and the fatty acids released from breakdown of triglyerides are delived to muscle and adipose tissue
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What are Chylomicrons?
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contain TG's move them thoughout blood steam
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What triggers the mobilzation of stored TG's
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LOW blood glucose levels
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What hormones are secreted in response to LOW BLOOD glucose and they activate
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epinephrine and glucagon--they activate adenylate cyclase
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Adenlate cyclase is causes
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activation of lipases which hydrolyzes TG'S making fatty acids
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When fatty acids leave the adipocyte they
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bind to the albumin
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What does albumin do
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transfs the insoluble fatty acids to skeletal muscle, heart and renal
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What hormones STIMULATE lipolysis
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epinephrine, norephinephrine, and glucagon, and adencortiotropic hormone
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What inhibits lipolysis
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INSULIN
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What products are the result of Lipases a TG's
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fatty acid, and Glycerol
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What happens to Glycerol
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is phosphorlated to form glycerdehyde 3-phosphate which enter glycolsis
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Can free Fatty acids pass into the mitochondria?
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NO
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How do fatty acids enter the INNER mitochondria
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activated to a fatty acyl-CoA and then forms fatty acyl carniting
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How does fatty acyl carnitine move into the mitochondrial maxtrix?
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facilitated diffusion through a transporter
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What happens to fatty acyl carnitine once in maxtrix
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fatty-acyl binds to Coa--remfroming fatty-acyl CoA, and releasing carnitine to return to intermembrane sapce
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Fatty acids oxidation takes place in
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3 stages
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What is stage 1 of Beta-Oxidation (ATP)
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removal of two carbons at a time forming actyl-CoA
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How many time does a 16 carbon fatty acid undgergo oxidation cycles and how many actyl-coA
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7 times---forming 8 Actyl coA
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What is stage 2 of Beta-Oxidation, and 3rd stage
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actyl coA are oxidized to CO2 in the CAC---electrons donated to ETC
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How many FADH2 and NADH are formed from a 16 carbon
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7 NADH and 7 FADH2
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How much water is generated in a 16 carbon fatty acid, and importance
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7 H20--how cameral and hibernating bears suvive without water
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What are 2 equations after 1 B-oxidation cycle
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8 Acetyl-CoA+ 7NADH + FADH2+7H20
8 Acetyl-CoA +28 ATP + 7H20 |
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What is results 2nd OXIDATION of FATTY ACIDS if Have orginal 16 cabons
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produce 3 NADH, 1 FADH2, and 1ATP (10 total) so multiple 8 x 10=80, and add to ATP of 1st cycle= 108
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How much CO2 and H20 produce in CAC
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2 CO2 and 2 H20
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Does oxidation of MONOunsaturated fatty acids require (has double bonds)
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YES, enzyme enoyl-CoA isomerase converts the cis double bond to a trans bond--which can undergo Beta-oxidation
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What does oxidation of Polyunstaturaed fatty acids require
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requires enoyl-CoA isomerase, and a REDUCTASE to form a trans bonds
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How are odd-number fatty-acids oxidized
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product of B-oxidation is prpionylCo-A which is converted to Succinyl-CoA which enter the CAC
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What happens during starvation with fatty acids?
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CAC is inactive, b/c its intermediates are used for gluconeogensis, thus actyl coA accumulates,
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What are to options for Actyl-CoA
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enter the CAC--or form Ketone Bodies
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What is benefit of forming Ketone-Bodies
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their production and releases CoA--which allows B-oxidation to continue
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MOA for ketone bodies formation
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2 actyl-CoA join by THIOLASE to form acetoaceyl-CoA (parent compound of 3 ketone bodies)
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Where do the reactions of ketone bodies occur
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maxtrix of liver mitochondria
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What are 2 final products of ketone formation
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acetone, and Hydroxybutrate
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Acetone-is exhalhed, but what is fate of hydroxbutrate
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passes into skeletal and heart muscle, and renal where is is converted to acetyl-CoA, and used as fuel
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What do increase levels of acetone and hydroxybutrate to do pH and cause
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lower pH, causing acidosis
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Wheres do most sugars, amino acids, and TG's pass via the blood to
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the liver--remain TG's enter adipose tissue
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Does the liver hetpocytes have remarkable flexibility?
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YES
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What happens to hepatocytes when diet is rich in protein
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increase enzymes required for AA catabolism and gluconeogenesis increase
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What happens to heptocyts when diet is right in starches
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AA enzymes decrease, and enzymes for carb metabolism increases
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The liver plats a cetnral processing and distribution roles in metabolism it supplies
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it supplies the appropriate mix of nutrients
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What is Glucokinase inhibited by compared to Hexokinase muscle
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muscle hexokinase is inhibited by G6P, NOT Glucokinase--b/c it regulated GLUCOSE AT HIGH CONCENTRATION
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What pathways can G6P go in liver
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1.leave as glucose
2.stored as glycogen 3.Enter CAC 4. Converted to Actyl-CoA Forms Cholestrol--Fatty Acid 5. Pentose Pathway |
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What is pathway in liver when glucose-6-phosphate is liminited
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converted to glucose--to maintain 5mM glucose levels
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What pathways are anabolic in Fates of Glucose-6-phosphate
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Pentose Phosphate, and converting actyl-CoA to lipid
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What are Fates of Amino Acids in Liver
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1. Precurose to liver proteins and other proteins
2. Precursors of nucleotides 3. Demainted and Degraged to Actyl CoA and CAC imtermeidates 4. Muscle amino acids |
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What is fate of Fattt acids
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1. Converted to liver lipds
2. Major fuel for liver and other tissue 3. Ketone Bodies 4. Actyl-CoA cholesterol/horomone production 5. converted to lipoproteins |
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What is brown-fat
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generates heat rather than ATP by decoupling oxidative phosphorlation
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How is heat generated by brown fat
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the uncoupling protein thermogenin
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What are the primary fuels for resting muscles
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fatty acids and ketone bodies--which are converted to Actyl CoA
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What does muscle contain for rapid energy production
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phosphocreatine
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Why does 02 continue to be used after exertion
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ATP is needed for gluconeogensis to replenish glyocgen storages
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Is Heart muscle COMPLETLY AEROBIC METABOLISM ONLY and why
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YES, mitcohondria make up almost half volume
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What type of thing fuel heart
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glucose, free fatty acids, and ketone bodies
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What is the type of fuel for brain
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glucose only, but can use ketone bodies if fasting
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What does insulin trigger
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that blood glucose is high, glucose is converted to glycogena and TG
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What does Glucagon trigger
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glycogen breakdown, glyconeogensis, and oxidizing fats
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Insulin increases fatty acid syntheisi and TG's and glycogen syntheis--so is it an important implication in diets
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YES
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How is insluin a self-regulating systme
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when blood glucose rises, catabolism occur increase ATP, closes K+, and open Ca+, which triggers insulin release
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During low blood glucose does Glucagon or Epinephrine stimulate glycolsis
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GLYCOLSIS IS ONLY STIMULATED IN Epinephrine
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Diabetes Mellitus I and II
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I-deffency in secretion
II-deffency in secretion and resistance |
