NAD+ regeneration the catabolism of pyruvate

Question 1

maintaining redox balance

Answer 1

Only limited amounts of NAD+ are present in a cell
Glycolysis reduces NAD+ to NADH + H+
NADH must be re-oxidised to let glycolsis continue
NADH+ is regenerated through the metabolism of pyruvate

Question 2

glycolysis and cellular respiration

Answer 2

glycolysis, in the presence of O2 pyruvate is oxidized which leads to the citris acid cycle, electron transport and CO2 and H2O

Question 3

glycolysis and fermentation

Answer 3

glycolsis, pyruvate absent of o2 leads to fermentation –> lactate or alcohol

Question 4

fate of glucose after glycolysis

Answer 4

pyruvate —> lactate, catalyzed by lactate dehydrogenase with the formation of NAD+ from NADH

Question 5

how does pyruvate get to ethanol

Answer 5

it loses a CO2 and becomes acetaldehyde, that is then broken down by alcohol dehydrogenase to become ethanol

Question 6

what happens in an anaerobic reaction

Answer 6

this is in the absence of oxygen
-alcohol fermentation
yeast and some microorganisms can form ethanol from pyruvate
-lactic acid fermentation
some microorganisms and humans can convert pyruvate to lactate

Question 7

what happens in an aerobic reaction

Answer 7

in the presence of oxygen
-pyruvate is further oxidised, and much more energy is released

Question 8

lactic acid fermentation

Answer 8

It takes place in many microorganisms such as cheese

Muscles during anaerobic exercise feel soreness due to low pH. It is eliminated in the liver, and heart and resting the working muscle

Plasma lactate during exercise predicts endurance performance

Question 9

what is the summary equation of the reactants and products in lactate fermentation

Answer 9

C6 H12 O6 + 2ADP + 2Pi —> 2 Lactate + 2 ATP

Question 10

Alcoholic fermentation

Answer 10

Takes place in some yeasts and some plants
-bread
- booze

Question 11

what is the summary equation of the reactants and products in alcoholic fermentation?

Answer 11

C6 H12 O6 + 2ADP + 2 Pi —> 2 ethanol + 2CO2 + 2ATP

Question 12

Glycolysis and fermentation summary or reactant and products

Answer 12

C6 H12 O6 —> 2 lactate (or 2 ethanol + 2CO2) + 2

Question 13

Glycolysis and cellular respiration summary of reactants and products

Answer 13

C6 H12 O6 +6O2 —> 6CO2 + 6H2O + 32 ATP

Question 14

Aerobic metabolism of pyruvate

Answer 14

pyruvate enters the mitochondria via a specific transporter

there the pyruvate dehydrogenase complex (PDC) catalyses sees the oxidative decarboxylation of pyruvate to acetyl- CoA

Question 15

what does the inner membrane of the mitochondria contain

Answer 15

contains proteins for the electron transport chain, ATP synthase, and transport proteins

Question 16

what does the inner membrane of the mitochondria contain

Answer 16

contains proteins for the electron transport chain, ATP synthase, and transport proteins

Question 17

what does the matrix of the mitochondria contain

Answer 17

contains enzymes of the TCA cycle

Question 18

explain the pyruvate dehydrogenase complex (PDC)

Answer 18

PDC consists of 3 enzymes involved in the actual reaction mechanisms (E1, E2, E3)

plus 2 enzymes involved in the control of PDC (kinase and phosphatase in a single polypeptide)

plus 5 coenzymes (thiamine, lipoic acid, conenzyme A, FAD, NAD+)