Midterm 2 Content Flashcards
What enzyme is not in the mitochondrial matrix in the Krebs cycle?
succinate dehydrogenase, bound to inner mitochondrial membrane
How many NADH and FADH2 yielded in Krebs?
3 NADH + H+ and 1 FADH2
Three irreversible reactions in Krebs
oxaloacetate–> citrate
isocitrate –> alpha-KTG
alpha-KTG–> succinyl CoA
What inhibits PFK in the liver?
excess citrate
anaplerosis
act of “filling in the gaps” to replenish diminished levels of metabolic intermediates
3 anaplerotic reactions in Krebs
- pyruvate –> oxaloacetate
- PEP –>oxaloacetate
- pyruvate –> malate
Electrons from NADH and FADH2 will be used in oxidation of H2O into O2 T/F?
false, reduction of O2 into H2O
What drives ATP synthesis
proton gradient and reduction of O2
oxidative phosphorylation
NADH and FADH2 are oxidized in the mitochondrial matrix while free energy from electron transfer will phosphorylate ADP using Pi
Where are ETC complexes located?
embedded within the inner mitochondrial membrane
What elements carry electrons in ETC?
FAD, FMN, ubiquinone, iron sulfur centers, cytochromes
How many protons and electrons can (Q) ubiquinone accept?
2 protons and 2 electrons one of each at a time
How many electrons does Fe3+ accept?
1 to generate Fe2+, and pass it along the chain
How many electrons do cytochromes accept or donate?
1 electron associated with outer orbitals of iron atom
Prosthetic groups and activity of Complex 1
NADH dehydrogenase
FMN and Fe-S complexes
Prosthetic groups and activity of Complex 2
succinate dehydrogenase
FAD, Fe-S
Prosthetic groups and activity of Complex 3
ubiquinone: cytochrome c oxidoreductase
Heme, Fe-S complexes
Prosthetic groups and activity of Complex 4
cytochrome oxidase
Hemes, copper binuclear centers (2!)
How many H+ removed by complex 1?
4
How many H+ removed by complex 2?
0
How many H+ removed by complex 3?
4
How many H+ removed by complex 4?
2
proton motive force (PMF)
imbalance of charge between matrix and inter membrane space. electrical gradient and chemical imbalance. High H+ in inter membrane space creates PMF
NADH and H+ yields how many H+?
10
FADH2 yields how many H+?
6
Every 4 H+ yields how many ATP?
1
How does ATP/ADP shuttle between matrix and elsewhere?
ATP-ADP translocate, antiport
What happens when ATP synthesis is disrupted (uncoupled)?
heat is generated.
Physiological uncoupling
brown adipose tissue. proton gradient disrupted by uncoupling protein-1 (thermogenin)
Chemical uncoupling
DNP, drug for weight loss, punched holes in the inner mitochondrial membrane disrupting the proton gradient
PDH makes how many ATP?
5
Krebs makes how many ATP?
20
Glycolysis makes how many ATP?
2 (+3 or +5)
NADH formed during glycolysis goes into what shuttles?
malate aspartate shuttle
glycerol-3-phosphate shuttle
In malate aspartate shuttle what has to transport oxaloacetate and NADH?
malate
How many ATP from malate aspartate shuttle?
5
How many ATP from glycerol-3-phosphate shuttle?
3
What inhibits cytochrome oxidase?
cyanide and carbon monoxide
What uncouples phosphorylation from ET?
DNP and uncoupling protein 1
Starting and end material for fatty acids?
acetyl-CoA
What delivers fatty acids to tissues?
albumin
Where does glycerol broken down form TAGs go?
glycolysis or gluconeogenesis!
Fatty acid degradation (lipolysis)
FA–> acyl CoA –> transfer to inner mitochondrial membrane –> four enzymes break to CoA-2 and acetyl CoA
When linked to carnitine, how do long chain fatty acids enter inner mitochondrial membrane?
carnitine acyltransferase I
Step 1 FA oxidation
oxidation of beta carbon by acyl CoA dehydrogenase generating CoA and FADH2
Step 2 FA oxidation
hydration of CoA by enol CoA hydratase generating L-3-hydroxyacyl CoA
Step 3 FA oxidation
oxidation of L-3-hydroxyacyl CoA by L-3-hydroxyacyl CoA dehydrogenase to generate 3-keotacyl CoA and NADH
Step 4 FA oxidation
cleavage of 3-ketoacyl CoA by beta-ketothiolase to generate acetyl CoA and FA chain 2 carbons shorter
How many bonds break in degradation in palmitate (16 C)?
7
How many acetyl CoA will be formed ?
8
How many molecules of ATP formed by oxidation of palmitate?
106 net. 108 total but uses 2
Where does ketone body synthesis take place?
liver
What intermediate in ketone body synthesis is used in cholesterol synthesis?
3-hydroxy-3-methyl-glutaryl CoA
For FA synthesis, what is the carrier for the acetyl groups from mitchondria to cytoplasm?
citrate
What is the enzyme that produces acetyl CoA from citrate?
ATP-citrate lyase
Where does oxaloacetate formed from citrate shuttle go?
Krebs cycle
What does citrate get turned into in the cytoplasm?
malonyl CoA
What is the rate limiting enzyme of FA synthesis?
acetyl CoA carboxylase, BIOTON REQURING
Fatty acid synthesis enzyme
fatty acid synthase
What is used as an electron donor in FA synthesis?
NADPH
At the end how many of __ in FA synthesis?
acetyl CoA: 8
ATP: 7
NADPH: 14
What is the precursor for TAGs and phospholipids?
phosphatidate
Phosphatidate + acyl CoA=
TAGs (Liver ER)
Phosphatidate + alcohol =
phospholipids (ER)
1st step of cholesterol synthesis
acetyl CoA and acetoacetyl CoA to for 3-hydroxy-3-methyl-glutaryl-CoA (cytosol)
Rate limiting enzyme in cholesterol synthesis
HMG CoA reductase to form mevalonate
How do phospholipids, triglycerides, cholesterol, and cholesterol esters transport?
packaged into lipoproteins
What form of cholesterol is stored in the body
cholesteryl esters
What is most important mechanism in managing heart disease?
controlling LDL