Chapter 18 (Pyruvate onward)

Question 37

What is the fate of pyruvate and NADH when O₂ is present (aerobic)

Answer 37

NADH is re-oxidized in the electron transport pathway, making ATP in oxidative phosphorylation

Pyruvate enters the citric acid cycle (TCA cycle)

Question 38

What is the fate of NADH and pyruvate when no O₂ is present (anaerobic)

Answer 38

NADH is re-oxidized to NAD⁺ providing additional NAD⁺ for more glycolysis

Pyruvate can go to lactate (muscle) or ethanol (yeast)

Question 39

To get the maximum energy gain glucose needs to (oxidized/reduced) to the level of ___

Answer 39

oxidized

CO₂

Question 40

Anaerobic glycolysis reaction

Lactate Dehydrogenase (LDH)

Answer 40

The ketone in pyruvate is reduced to a hyrdoxyl group (-OH) and a NADH is oxidized to a NAD+

Reversible

Occurs in the muscle

Question 41

The NAD+ created in Lactate Dehydrogenase is then used in the ___ enzyme reaction

Answer 41

GADPH

Question 42

What is the net yield when anaerobic glycolysis takes place

Answer 42

NADH = 0

Pyruvate = 0

ATP = 2

Question 43

NAD⁺ to NADH + H is (oxidation/reduction)

Answer 43

Reduction

NAD⁺ gained an electron

Question 44

Anerobic fermentation reaction

(Step 1)

Pyruvate Decarboxylase

Answer 44

Pyruvate is decarboxylated at the C#3/4 (removal of CO₂) which produces Acetaldehyde (which is only 2 C’s)

Irreversible

Question 45

Anaerobic fermentation

(Step 2)

Alcohol Dehydrogenase

Answer 45

The aldehyde on Acetaldehyde is reduced to a primary alcohol which produces Ethanol

a NADH + H is oxidized during this reaction to NAD⁺

Question 46

Decarboxylase

Answer 46

Removes a carbondioxide

These reactions are usually irreversible

Question 47

What does the drug Disulfiram do for the treatment of alcoholism

Answer 47

It inhibits the enzyme Aldehyde Dehydrogenase which causes a person to become violently ill when they drink alcohol becasue they cannot convert Acetaldehyde to Acetate

Question 48

Thiamine Pyrophosphate (TPP)

Answer 48

Found in Thiamine (vitamin B₁)

Carries actived aldehyde groups

Goes into the ylid form so that the C^- on the ring can attack the middle C in Pyruvate

Question 49

Pasture affect

Answer 49

Yeast consumes more sugar when grown under anaerobic conditions

Question 50

The rate of ATP production via anaerobic glycolysis can be up to ___ times faster than that of ___ and is not done all the time in tissues because

Answer 50

100x

Oxidative phosphorylation

This is not done all the time in tissues because it requires more glucose and produces more waste products (lactate)