Biochem Processes

Question 1

Any dehydrogenases before vs after pyruvate

Answer 1

NAD+ –> NADH vs NADH –> NAD+ (except when malate becomes oxaloacetate)

Question 2

Any kinases before vs after pyruvate

Answer 2

ADP+ –> ATP vs ATP –> ADP+

Question 3

Pyruvate carboxylase and acetyl CoA carboxylase also has what buddy?

Answer 3

biotin

Question 4

PEP carboxykinase releases what energy?

Answer 4

GTP –> GDP and CO2

Question 5

Pyruvate decarboxylase also has what buddy?

Answer 5

TPP

Question 6

Which enzymes have biotin or TPP as buddies?

Answer 6

Pyruvate carboxylase and acetyl CoA carboxylase has biotin; pyruvate decarboxylase, E1, and transketolase has TPP

Question 7

High glycolytic and Kreb cycle intermediates and/or low AMP stimulate what process vs low intermediates and/or high AMP stimulate what process?

Answer 7

Gluconeogensis vs glycolysis

Question 8

A single glu molec produces how many NADH in cell respiration?

Answer 8

10: 2 in glycolysis, 2 in pyruvate dehydrogenase complex (converts pyruvate to acetyl CoA), and 6 in Kreb’s cycle

Question 9

Irreversible steps of glycolysis

Answer 9

How Glycolysis Pushes Forward the Process: Kinases

Hexokinase, glucokinase (present in liver and pancreas), PFK-1, pyruvate kinase

Question 10

What’s the starting material for Krebs cycle? For gluconeogenesis?

Answer 10

Acetyl CoA. Pyruvate or lactate (and maybe glycerol)

Question 11

Briefly describe anaerobic fermentation. How does fermentation help?

Answer 11

Basically glycolysis w/o O2 (so if glycolysis = inhibited —> you can’t have anaerobic fermentation either)
Help oxidize NADH into NAD+, can recycle

Question 12

How many ATP is produced per NADH and FADH2?

Answer 12

2.5 ATP per NADH, 1.5 ATP per FADH2

Question 13

Describe the carnitine shuttle for FA [O]

Answer 13

1) acyl CoA synthetase uses ATP to react FA with CoA-SH to yield acyl CoA
2) carnitine acyl transferase I attaches carnitine to acyl CoA (CoA-S becomes a leaving group) to yield acyl carnitine; this is the rate limiting step, malonyl CoA inhibits CAT I
3) acyl carnitine diffuse from cytoplasm into intermembrane space thanks to porins that made the OMM porous
4) acyl carnitine translocase guides acyl carnitine from intermembrane space to matrix b/c IMM isn’t porous
5) carnitine acyl transferase II attaches CoA back to FA and kicks out carnitine to yield acyl CoA
6) acyl CoA undergoes beta [O] and indirectly ETC to yield acetyl CoA and shorter acyl CoA (the new acyl CoA lost 2 carbons)

Question 14

DeltaG for anabolic (monomer to polymer) vs catabolic (polymer to monomer) rxns

Answer 14

> 0, energy-requiring rxns vs < 0, energy-releasing rxns

Question 15

Describe FA synthesis

Answer 15

Acetyl CoA can’t diffuse from mito to cyto, but citrate can. Citrate diffuses from mito to cyto —> citrate lyase breaks cit into acetyl CoA and oxalo —> oxalo can be converted back to pyruvate and yield NADPH in the process; acetyl CoA carboxylase, ATP, and CO2 converts acetyl CoA to yield malonyl CoA and ADP + Pi —> FA synthase and 2 NADPH converts malonyl CoA to yield palmitic acid (C16H32O2), water, and CO2

Question 16

FA synthesis overall eqn

Answer 16

8 acetyl CoA + 7 ATP + 14 NADPH —> palmitic acid (C16H32O2) + 7 ADP + 7 Pi + 14 NADP+ + 6 H2O + 8 CoA

Question 17

Describe ETC. Is it endergonic or exergonic? How does flow of e- change in anabolic vs catabolic rxns?

Answer 17

NADH goes thru complex I and FADH2 goes thru complex II —> Coenzyme Q/ubiquinone (small, hydrophobic –> moves freely in inner mito membrane) —> complex III —> cytochrome c (sticks out in matrix side) —> complex IV —> O2 = last e- acceptor —> becomes water. Energy released from moving b/w complexes drives H+ from matrix to intermembrane space; ATP synthase uses H+ gradient (moving from intermembrane space to matrix) to make ATP from ADP+Pi
Exergonic
flow of e- inc vs dec

Question 18

Chemiosmosis

Answer 18

Mechanism that couples proton motive force and ATP synthesis (done by ATP synthase)

Question 19

Substrate level phosphorylation vs oxidative phosphorylation. In what processes does each occur?

Answer 19

Make ATP by directly adding phosphate group from substrate to ADP, happens in glycolysis and Krebs vs make ATP by oxidizing e- carriers in presence of oxygen, happens in ETC

Question 20

Is ATP hydrolysis endergonic or exergonic?

Answer 20

Exergonic

Question 21

Complex I of ETC

Answer 21

Site where NADH goes and = oxidized by NADH dehydrogenase. 4 p+ = pumped from matrix to intermembrane space

Question 22

What does NADPH do?

Answer 22

Help with FA synthesis, cholesterol and steroid hormone synthesis, prevent oxidative damage from reactive O2 species. DOESNT OXIDIZE CHOLESTEROL IN LIVER

Question 23

Pyruvate dehydrogenase aka PDH = inhibited by what?

Answer 23

acetyl CoA

Question 24

What happens to lactate that has been released into blood in lactic acid fermentation?

Answer 24

Can become glu in liver or pyruvate in muscle, heart, or brain cells

Question 25

Reversible and irreversible steps of PPP

Answer 25

non-oxidative phase: Ru5P <=> R5P vs oxidative phase: G6P = [O] is form 6-phosphogluco-delta-lactone --> 6-phosphogluconate, and 6-phosphogluconate --> Ru5P

Question 26

GLUT1 vs GLUT2 vs GLUT4

Answer 26

glucose transporter into cell vs glucose transporter into cell; found in liver, intestines, kidneys, beta islet cells of pancreas vs glucose transporter into cell, insulin-regulated, found in adipose tissue and striated muscle (ie. skel and cardiac muscle). All to do glycolysis

Question 27

Any rxn in the body = spont

Answer 27

so all rxns in body will have deltaG<0

Question 28

F0 vs F1 of ATP Synthase

Answer 28

proton channel embedded in membrane vs ATP synthesis that sticks into matrix

Question 29

Is water a product of glycolysis?

Answer 29

Yep