TCA Flashcards
(31 cards)
H2O moves out of what part of the loop of henel
descending, as go deeper into the medulla osmolarity gets greater so water leaves to dilute
what hormone do alcohol and caffeine affect?
inhibit ADH —> aquaporin in collecting duct
why does glucokinase have a higher km than hexokinase
want to ensure that other parts of the body gets the first crack at the glucose
what differences are there in the feedback mechanisms of glucokinase and hexokinase
- glucokinase is indices by insulin, hexokinase is not
- hexokinase is inhibited by excess G6P, glucokinase is not
the rate-limiting step of glycolysis
PFK1. ( catalyze fructose 6-p —-> fructose 1,6 bisp)
PCT vs DCT
PCT- right after the Bowen capsule where aa, glucose, vitamins, salts, h2o are reabsorbed
- concentration and ph of filtrate through the kidney
DCT- after the loop of henel, this is where aldosterone can have an impact- reabsorb sodium and water
- concentration and ph of urine
pyruvate has 3 fates
Oxaloacetate, lactic acid, acetyl CoA
fermentation
reduce pyruvate to lactic acid in order to oxidize NADH —> NAD+
pyruvate decarboxylation
right after glycolysis, in mito matrix
- pyruvate is oxidized to CO2, NAD+ is reduced and acetyl-CoA is produced
what enzyme pyruvate —-> acetyl-CoA
pyruvate dehydrogenase complex (PDH)
what activates PDH
insulin
what inhibits PDH
NADH and its product acetyl CoA
what’s important in PDH complex
B1, lipoic acid, Mg2+, pyrophosphate, FAD, NAD+
the main goal of TCA
to oxidize acetyl CoA to Co2 and H2O while reducing NAD+ and FAD
is PDH rxn spontaneous
yes very
how is CoA bonded to the acetyl group
thioester bond - creates a huge amount of energy when broken
can alcohol get converted to acetyl CoA?
yes, by alcohol dehydrogenase BUT NADH build-ups up which inhibits TCA, therefore, a lot of the acetyl coa made from alcohol gets converted to FA
synthases vs synthetases
with “e” needs energy input
- both form new covalent bonds
rate limiting step of TCA
isocitrate dehydrogenase
- and first step when NADH is produced and CO2 is lost
what steps reduce NAD+ and lose CO2
step 3 and 4
- iso–> keto (rate lim)
- keto- succinyl-coA
what step reduces FAD
step 6 (succinate to fumigate) y succinate dehydrogenase
what step generates ATP and why/how?
succinyl-CoA—> succinate + CoA-SH
bc the high energy thioester bond is hydrolyzed -RELEASES a shit ton of energy - enough to couple with GDP–> GTP
whats the last step that reduces another NAD but no Co2 is produced?
step 8 (malate –> oxaloacetate + NADH)
- enzyme is malate dehydrogenase ( the same as the aspartate-malate shuttle= 2.5 ATP)
how to remember the order of TCA
Please Can I….. keep selling seashell for money, officer?
