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Biochem test 3-2
lectures 26-29
86
Biochemistry
Graduate
03/15/2011

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Term
what is the end product of aerobic glycolysis
Definition
pyruvate
Term
what is pyruvate converted to?
Definition
acetyl CoA
Term
what is the endproduct of anaerobic glycolysis
Definition
lactate
Term
how many ATPs are made for each glucose>>>lactate
Definition
2
Term
what is oxidative branch?
Definition
glucose > ribulose-5-P
Term
oxidative branch: reversible?
Definition
no
Term
what is non-oxidative branch?
Definition
ribulose 5-P to ribose-5-P etc
Term
is non-oxidative branch reversible?
Definition
yes
Term
G6PDH deficiency
Definition
drug-induced hemolytic anemia
Term
what is the purpose of liver fatty acid/TAG biosynthesis and adipose TAG re-synthesis?
Definition
storage of excess dietary fuel for use during fasting states
Term
where does fatty acid biosynthesis occur?
Definition
cytoplasm
Term
in general, how is a fatty acid synthesized?
Definition
repetitive 2 carbon units attached to a hydrocarbon, which is covalently attached to an acyl carrier protein (ACP) while being extended
Term
what is the first step of fatty acid synthesis?
Definition
formation of malonyl-CoA by acetyl CoA carboxylase
Term
what is the fatty acid storage form in adipose
Definition
triacylglycerols (TAGs)
Term
where does triacylglycerol synthesis start?
Definition
liver
Term
what are liver TAGs packaged in?
Definition
VLDL
Term
what does VLDL do?
Definition
packages liver TAGs and takes them through the blood to adipose and other tissues
Term
glycogen synthase: whish is active and which is inactive?
Definition
dephosphorylated (a) is active
phosphorylated (b) is inactive
Term
what is the effect on glycogen synthesis when insulin is present
Definition
insulin>>>phosphatase>>>dephosphorylates glycogen synthase>>>glycogen synthesis
Term
what is the effect on glycogen synthesis when glucagon or epinephrine is present?
Definition
glucagon/epinephrine>>>cAMP-activated PKA phosphorylates glycogen synthase>>>inhibits synthase>>>glycogen breakdown
Term
what are the 2 ways that the body makes ATP?
Definition
1) substrate level phosphorylation, using chemical energy of high energy intermediates
2) REDOX energy (oxidative phosphorylation)>>>preferred
Term
where do reducing equivalents end up in aerobic metabolism?
Definition
water
Term
where do reducing equivalents end up in anaerobic metabolism?
Definition
lactate
Term
another function of shuttling systems other than getting the reducing equivalents into the mitochondria
Definition
recycling NAD and FAD
Term
if the glycerol phosphate shuttle is used, how many ATP are produced
Definition
30
Term
if the malate shuttle is used, how many ATP are produced?
Definition
32
Term
2 functions of ETC
Definition
1) make ATP
2) recycle NAD and FAD so that ATP production can continue
Term
where is LDH located
Definition
cytoplasm
Term
structure of glycogen
Definition
insoluble, glucose in linear alpha-1,4-linkages and branched alpha-1,6-linkages
Term
2 places where glycogen is synthesized most often
Definition
liver and resting musclre
Term
where does pentose shunt take place? (organ and area of cell)
Definition
liver; cytoplasm
Term
main function of pentose shunt?
Definition
creation of NADPH for fatty acid biosynthesis
Term
where does TAG biosynthesis occur
Definition
liver
Term
which tissues use glucokinase and which use hexokinae?
Definition
glucokinase: liver and adipose. everywhere usees hexokinaser
Term
2 products of pentose shunt
Definition
NADPH for fatty acid biosynthesis
Ribose-5-P for nucleotides (dividing cells)
Term
3 products of oxidative branch of pentose shunt
Definition
CO2
NADPH
ribulose-5-P
Term
why is oxidative branch irreversible?
Definition
makes a CO2
Term
how does the oxidative branch of pentose shunt begin (enzyme?)?
Definition
glucose-6-phosphate dehydrogenase converts glucose-6-phosphate to ribulose-5-phosphate
Term
high levels of NADPH is maintained by what
Definition
pentose shunt
Term
what are the enzymes of the non-oxidative branch of the pentose shunt
Definition
transketolase and transaldolase
Term
what does transketolase (non-oxidatve branch, pentose shunt) REQUIRE
Definition
TPP (thiamine pyrophosphate)
Term
what hapens with a thiamine deficiency?
Definition
TPP sucks, so transketolase is inhibited and non-oxidatve branch of pentose shunt sucks too
Term
in the pentose shunt, of R-5-P isn't needed, what happens
Definition
it is converted back into glycolytic intermediates
Term
what step of the pentose shunt is regulated
Definition
think: first step
G6PDH
Term
which hormone induces G6PDH
Definition
insulin
Term
what inhibits G6PDH
Definition
think pentose shunt...product?
NADPH
Term
why is a reducing environment important for RBCs
Definition
1) to protect membranes against ROS
2) keep iron in reduced Fe 2+ state
Term
oxidized state of iron?
Definition
Fe 3+
Term
reduced state of iron
Definition
Fe 2+
Term
G6PDH deficiency causes what
Definition
normally, no problem, bc supply exceeds need
with drugs, causes drug-induced hemolytic anemia
Term
what is activated form of Glucose-6-phosphate
Definition
UDP-glucose
Term
if u need to add glucose to something, what form do u want it in
Definition
UDP-glucose
Term
what does phosphoglucomutase do and in what kind of reaction
Definition
converst G6P to G1P

activation of UDP-glucose

it's reversible
Term
what is added to G1P to make UDP-glucose
Definition
UMP
Term
what is the energy cost of adding one glucose
Definition
2 high energy bonds
Term
what provides reducing equivalents for fatty acid biosynthesis?
Definition
NADPH
Term
How does acetyl CoA reach the NADPH in the cytoplasm if it is made in the mitochondria?
Definition
The TCA cycle changes it to citrate, it goes into the cytoplasm, and is cleaved back into acetyl CoA
Term
purpose of ATP citrate lyase?
Definition
to convert citrate back into acetyl CoA because the reaction is very endergonic
Term
function of acetyl CoA carboxylase?
Definition
first step of fatty acid biosynthesis: converts Acetyl-CoA (with Bicarbonate) to make Malonyl-CoA
Term
what does the first step of fatty acid biosynthesis require?
Definition
ATP
Term
what does biotin carry?
Definition
carboxyl groups
Term
what is the key regulated enzyme in fatty acid biosynthesis
Definition
acetyl Co-A carboxylase
Term
what is the activated form of Acetyl CoA?
Definition
Malonyl CoA
Term
in fatty acid synthesis, how are acyl groups carried
Definition
as thioesters of cysteine OR as phosphopantethiene
Term
essential cofactor for fatty acid synthase?
Definition
phoshpopantetheine
Term
essential cofactor for acetyl co-A carboxylase?
Definition
biotin
Term
what is initiation reaction of fatty acid synthesis?
Definition
Acetyl CoA and Malonyl CoA charge ACP. Condensation reaction occurs, CO2 is released, and Acetoacetyl ACP is formed
Term
3 phases of "remodeling" of the fatty acid chain
Definition
1. reduction
2. dehydration
3. reduction
Term
how many NADPH are needed for the elongation phase of fatty acid synthesis
Definition
2 (bc there are 2 reduction phases)
Term
what is final product of elongation phase of fatty acid synthesis
Definition
fatty acyl Co-a
Term
how many acetyl-CoA's are needed for elongation phase?
Definition
8
Term
how many malonyl-CoA's are needed for elongation phase of fatty acid synthesis?
Definition
7
Term
how many ATP's are needed for elongation phase of fatty acid synthesis?
Definition
7
Term
how many NADPH's are needed for elongation of fatty acid synthesis
Definition
14 (7 cycles x 2 NADPH for 2 reduction phases)
Term
what is the activated form for fatty acids?
Definition
fatty acyl coA esters
Term
how is phosphatidate synthesized
Definition
from DHAP and fatty acyl coA esters
Term
what enzyme is used to make phosphatidate
Definition
acyltransferase
Term
how many acyl groups does phosphatidate have
Definition
2
Term
when VLDL-TAGs reach adipose tissue, what happens?
Definition
Free fatty acids are cleaved off and used to resynthesize TAGs for storage in adipose
Term
insulin's effect on liver
Definition
increases glycogen production, TAG/fatty acid biosynthesis, decreases glucose production
Term
Summarize Carbo-Fat pathway
Definition
glucose>pyruvate>Acetyl CoA>Citrate>Acetyl CoA>Malonyl Co A> fatty acid
Term
what enzyme activates acetyl CoA carboxylase?
Definition
citrate (feed forward)
insulin
Term
What inhibits Acetyl Co A carboxylase
Definition
Palmitoyl Co A
glucagon
Term
what can't insulin and glucagon regulate?
Definition
things inside the mitochondria (PDH and ATP citrate synthase)
Term
what pathway is glucose6-phosphate dehydrogenase in
Definition
pentose shunt
Term
insulin induces pentose shunt why?
Definition
bc we need NADPH
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