Unit 1 Review Flashcards
Glycolysis
Breaks 6C glucose into 2 3C pyruvate, forming 2 net ATP
Citric Acid Cycle
Oxidizes acetyl CoA into 2 CO2, 3 NADH, 1 FADH2, 1 GTP
Where does glycolysis occur?
The cytoplasm
Where does the citric acid cycle occur?
The mitochondrial matrix
PDH E1
Pyruvate Dehydrogenase (“Poor Drivers Don’t Take Defensive Driving” mnemonic)
PDH E2
Dihydrolypoyl Transacetylase (“Poor Drivers Don’t Take Defensive Driving” mnemonic)
PDH E3
Dihydrolipoyl Dehydrogenase (“Poor Drivers Don’t Take Defensive Driving” mnemonic)
What does the PDH complex do?
Converts pyruvate to acetyl CoA
What are the cofactors associated with PDH?
TPP, Lipoamide, CoA, FAD, NAD+
Defining features of PDH steps
1) TPP E1 decarboxylates pyruvate, forming hydroxyethyl
2) Hydroxyethyl to dihydrolipoamide
3) Transesterification to Acetyl CoA
4) E3 takes protons from E2 (SH - DS)
5) E3 transfers protons to FAD, then NAD+
What is the rate-limiting step of the citric acid cycle?
Enolate formation during citrate synthase rxn
Citric Acid Cycle Mnemonic
Can I Keep Selling Seashells for Money, Officer?
During which steps of the citric acid cycle are NADH formed?
Isocitrate dehydrogenase (+CO2), AKG dehydrogenase (+CO2), malate dehydrogenase
During which step of the citric acid cycle is FADH2 formed?
Succinate Dehydrogenase
During which step of the citric acid cycle is GTP formed?
Succinyl CoA synthetase
Which enzyme in the citric acid cycle has a covalently bound FAD?
Succinate dehydrogenase (same one that produces FADH2)
Which reaction in the citric acid cycle is endergonic?
Malate –> OAA (malate dehydr.)
How many ATP generated per NADH?
2.5
How many ATP generated per FADH2?
1.5
Pyruvate dehydrogenase kinase _________ the PDH complex, insulin ________ activates.
PDK inhibits, insulin activates
Allosteric inhibition of CAC
NADH and Acetyl CoA slow cycle
3 Mechanisms of CAC Flux Control
Substrate Availability (e.g. OAA)
Product inhibition
Competitive feedback inhibition (e.g. NADH, acetyl CoA)
Glyoxylate Cycle
Formation of OAA from 2 molecules acetyl CoA, skipping the CO2-producing step. Plants, bacteria, fungi (glyoxysome).
What are the two new enzymes associated with the glyoxylate cycle?
Isocitrate lyase
Malate synthase
What are the three substances that can freely diffuse through the IMM?
CO2, H2O, O2
Malate-Aspartate Shuttle
Moves OAA into the matrix by temporarily converting it back to malate (AST Rxn). Heart, liver, kidneys.
Glycerophosphate Shuttle
Lets NADH’s electrons enter the ETS via FADH2, regenerating NAD+ for the CAC
What molecule carries the electrons between CI, CII, and CIII?
CoQ/Ubiquinone
What molecule carries the electrons between CIII and CIV?
Cytochrome C
How many alpha-beta subunits in F1 of ATP synthase?
3
Open conformation
Can’t bind nucleotides
Loose conformation
Can bind ADP and Pi
Tight conformation
Can bind ATP
What are the two gradients in the chemiosmotic model?
Electric and chemical gradients
How many C subunits in human ATP synthase?
8 subunits
What residue on ATP synthase picks up protons?
Glu or Asp
P/O Ratio
Protons into IMS/4 protons per ATP
2,4-DNP
Can cross membrane; dissipates gradient by grabbing protons then diffusing back into the matrix.
Brown Adipose Tissue
UCP1 allows protons to reenter the matrix without going through ATP synthase
Where do the light reactions take place?
Thylakoid Membrane
Where is the high proton concentration generated during the light reactions?
Thylakoid lumen
What does photosystem II do?
Oxidizes H2O, releases O2, and generates ATP
What does photosystem I do?
Reduces NADP+
Where does the Calvin Cycle occur?
Stroma
What can be produced by G3P and DHAP isomerization?
Amylose, amylopectin, cellulose, sugars
What happens if rubisco incorporates O2 instead of CO2?
Intermediate makes 1 G3P, 1 2-phosphoglycolate; glycolate to peroxisome for conversion to G3P (costs ATP, NADH)
