Lecture 20: Anaerobic Fermentation

Question 1

How much energy is harvested from conversion of one glucose to 2 pyruvate molecules?

Answer 1

-2 ATP
-2NADH

Question 2

Oxidative phosphorylation

Answer 2

1. oxidation: electrons transferred from NADH and FADH2 to O2
   -harvest ATP
   -electron transfer coupled with transfer of protons across membrane to generate proton-motive force
2. Phosphorylation: ATP synthase produce ATP using proton motive force

Question 3

Where does oxidative phosphorylation occur?

Answer 3

mitochondrial inner membranes

Question 4

Energy yield of oxidative phosphorylation

Answer 4

-2.5 ATP per NADH
-1.5 ATP per FADH2

Question 5

Energy yield of complete oxidation of glucose to CO2 and H20 by glycolysis, TCA cycle, and oxidative phosphorylation

Answer 5

32 ATP

Question 6

Anaerobic Fermentation

Answer 6

-oxidative phosphorylation cannot occur without oxygen
-instead pyruvate must be REDUCED to lactate using 2 NADH
-cytosol
= 2 lactate + 2 ATP

Question 7

ATP generation in red blood cells

Answer 7

-only by anaerobic fermentaition
-they have no mitochondria

Question 8

Lactate

Answer 8

-decreases INTRAcellular pH which inhibits glycolysis
-too much may decrease BLOOD pH

Question 9

lactic acidosis

Answer 9

-decrease of blood pH bc of excess lactate
-hypoxia, exercise, liver disease, ethanol, thiamin deficiency

Question 10

Fate of Lactate

Answer 10

-transported with H+ to blood stream
-converted to pyruvate again where O2 supply is sufficient

Question 11

lactate-H+ symporter

Answer 11

-transfers lactate and H+ from cytosol to blood stream

Question 12

Ethanol Fermentation

Answer 12

-yeast converts pyruvate to ethanol when no oxygen
-ethanol later converted to acetate (used as energy source) when oxygen available
-bread and alcohol

Question 13

Pyruvate decarboxylasse

Answer 13

-pyruvate to ethanol
-NADH to NAD+

Question 14

Pyruvate dehydrogenase complex

Answer 14

-mitochondria
-catalyzes pyruvate to acetyl CoA
-IRREVERSIBLE
-INHIBITED by Aceytl CoA
-3 enzymes

Question 15

Pyruvate dehydrigenase enzymes

Answer 15

E1: pyruvate dehydrogenase
E2: dihydrolipoyl TRANSacetylase
E3: hihydrolipoyl DEHYDROGENASE

Question 16

Acetyl CoA

Answer 16

-produced from glucose, fatty acids, some amino acids (ketogenic)
-fuel TCA cycle
-material for fatty acid synthesis and ketogenesis
-CANNOT make glucose

Question 17

Acetyl CoA produced by:

Answer 17

-pyruvate
-fatty acids
-ketogenic amino acids

Question 18

Acetyl CoA produces

Answer 18

-CO2
-ketone bodies
-fatty acids
-cholesterol

Question 19

Tricarboxylic Acid (TCA) cycle

Answer 19

-mitochondria
= 2 CO2
= 3 NADH, 1 FADH2, 1 GTP

-TOTAL concentration of intermediates does not change

Question 20

TCA intermediates

Answer 20

-building blocks for gluconeogenesis and amino acid synthesis (neurotransmitters)
-decrease in concentrations slow down utilization of acetyl CoA and energy production

Question 21

Citrate use

Answer 21

-fatty acid and sterol synthesis

Question 22

a-Ketoglutarate use

Answer 22

-amino acid synthesis
-neurotransmitters

Question 23

Succinyl CoA use

Answer 23

-heme synthesis

Question 24

Malate use

Answer 24

gluconeogenesis

Question 25

Oxaloacetate use

Answer 25

-amino acid synthesis

Question 26

Anaplerotic reactions

Answer 26

-supply TCA intermediates -when amino acids are not sufficient (growing cells), pyruvate is main source

Question 27

Pyruvate carboxylase

Answer 27

-catalyzes most important anaplerotic reaction -NEED for gluconeogenesis -High in liver and nervous tissue -pyruvate to oxaloacetate

Question 28

Pyruvate carboxylase deficiency

Answer 28

-severe lactic acidosis -infant death -triheptanoin treatment

Question 29

Triheptanoin

Answer 29

-treat pyruvate carboxylase deficiency -triglycerid with fatty acid -converted to succinyl CoA

Question 30

Glycolysis and TCA summary

Answer 30

-in: glucose -out: 6 CO2 -energy harvested: 2 ATP, 2 GTP, 10 NADH, 2 FADH2