quiz 7 Flashcards
for step 0 of cac
substrate:
product:
enzyme
pyruvate, CoA, NAD+
NADH, acetyl CoA
pyruvate dehydrogenase complex
also uses TPP, lipoate, FAD
how is pyruvate transported to the mitochondria
tramsmembrane transporter proteins
what does a low EC mean
pyruvate is metabolized by pyruvate dehydrogenase and acetyl CoA and CO2 is formed
what are the 5 enzymes needed for step 0
NAD+/NADH
FAD/FADH2
CoA
TPP
a-lipoic acid
describe NAD+
derived from niacin (B3)
transfers 2e- at once leaving H-
pellagra is a B3 deficiency
describe FAD
derived from riboflavin (B2)
reduced to FADH2 by transferring 2e-
transfers one e- at a time when
cheilosis is a B2 deficiency
describe CoA
derived from panthothenic acid (B5)
cofactor for fatty acid, acetyl choline, heme, cholesterol
required for energy conversion in cac
a deficiency is rare
how does CoA cross the membrane
CoA is degraded by enzymes to B5
crosses membrane and reverts to CoA
ATP and cys are added
describe TPP
derived from thiamine (B1)
absorbed in gut and phosphorylated
beriberi is a B1 deficiency
describe a-lipoic acid
synthesized in plants and animals (esp broccoli, liver, spinach, tomatoes)
provides disulphide for redox rxn
receives acetyl from TPP and transfers it to CoA
describe rxn 0
occurs before cycle begins
irreversible
pyruvate changes to acetyl CoA
define oxidation
loss of e-
define reduction
gain of e-
define oxidant
oxidize other molecules, accepts e-, reduced
define reductant
reduce other molecules
donates e-
oxidized
define coupled rxn
combined 2 half rxns with a common intermediate
standard reduction potential
free energy
which steps are regulated
0, 1, 3, and 4
what is the net rxn for CAC
acetyl CoA + 3NAD+ + FAD + GDP + Pi + 2H2O —-> CoA + 2CO2 + 3NADH + 3H+ + FADH2 + GTP
step 1
substrate:
product:
enzyme
acetyl CoA, oxaloacetate, H2O
citrate, CoA
citrate synthase
step 2
substrate:
product:
enzyme
citrate
isocitrate
aconistase
step 3
substrate:
product:
enzyme
isocitrate, NAD+
a-ketogluterate, NADH, CO2
isocitrate dehydrogenase
step 4
substrate:
product:
enzyme
a-ketogluterate, NAD+, CoA-SH
succinyl-CoA, NADH, CO2
a-ketogluterate dehydrogenase
step 5
substrate:
product:
enzyme
succinyl-CoA, Pi, GDP
succinate, CoA, GTP
succinyl-CoA synthetase
step 6
substrate:
product:
enzyme
succinate, FAD
fumarate, FADH2
succinate dehydrogenase
step 7
substrate:
product:
enzyme
fumarate, H2O
malate
fumerase
step 8
substrate:
product:
enzyme
malate, NAD+
oxaloacetate, NADH+H+
malate dehydrogenase
what is the regulation of pyruvate dehydrogenase
regulated by energy charge
what is citric acid used for
commercial food preservation
how is redox power generated
oxidizing acetyl CoA and reducing NAD and FAD
how many intermediates are shared by other pathways
5
where does the majority of ATP come from
oxidative phosphorylation
what is oxidative phosphorylation powered by
chemiosmosis
define chemiosmosis
chemical osmosis
pumps protons
define crista
folds of the inner membrane where ATP synthase occurs
define matrix
aqueous interior of mitochondria where CAC occurs
how is ATP produced
when H+ flows through ATP synthase
describe slow muscle twitches
aerobic energy
long periods of
more mitochondria
describe fast muscle twitches
aerobic energy
short bursts
less mitochondria
describe chloroplast in the plant cells
analogous to mitochondria
uses light energy
circuit is flipped
what is potential energy modified to
work
define ATP synthase
motor that preforms work
define uncoupler
circuit continues but via an alternate route
define inhibitor
blocks circuit and stops the floe
what does uncoupleS oxidative phosphorylation do
allows H+ to flow without ATP synthase
what does a low pH cause? a high pH?
pronation
depreciation
define oligomycin
blocks protein circuit
creates a high pH in matrix
causes cellular death
