Cell Biology Exam Two - Fermentation and Gluconeogenesis

Fermentation:

anaerobic process but not anaerobic respiration

What does respiration refer to?

Respiratory Electron Transport Chain

Where does fermentation occur in Prokaryotes and Eukaryotes?

Cytoplasm

What is the circumstance needed for fermentation?

Needs deprivation of oxygen

Fermentation regenerates

NAD+

In fermentation coenzyme concentrations are

low

need to recycle ___ back to ____

NADH

NAD+

In fermentation there is no _____ electron acceptor

external

What is the internal electron acceptor?

pyruvate

In fermentation where do electrons and hydrogen ions go?

pyruvate

Who does lactate fermentation?

Some bacteria cells

Muscle cells

What is the enzyme involved in lactate fermentation?

lactate dehydrogenase

What does this represent?

Lactate Fermentation

Is lactate fermentation a ____ reaction

reversible

Alcoholic fermentation requires ___ steps

two

What is the first step of alcoholic fermentation?

pyruvate loses a carbon (CO2) and is converted to acetylaldehyde

What is the second step of alcoholic fermentation?

NADH reduces acetaldehyde to ethanol

What enzyme(s) are involved in alcoholic fermentation?

Pyruvate decarboxylase

Alcohol dehydrogenase

What does this represent?

Alcoholic fermentation

What are some other fermentation pathways?

Propionate fermentation

Acetone

Isopropyl alcohol

Butyrate

ATP count for glycolysis and fermentation

Glycolysis =

2 (net)

ATP count for glycolysis and fermentation

Fermentation =

0 (net)

NADH count for glycolysis and fermentation

Glycolysis =

2 (net)

NADH count for glycolysis and fermentation

Glycolysis fueled by fermentation =

2 (net)

What is the purpose of fermentation?

allows glycolysis to continue by freeing up NAD+

Gluconeogenesis is the formation of

“new” glucose

In gluconeogenesis you are making glucose from

3 and 4 carbon precursors

What are the most common precursors in gluconeogenesis?

pyruvate

oxaloacetate

Most gluconeogenesis reactions are simply glycolysis reaction in

reverse

Is gluconeogenesis reversible

no (bypass reactions)

Reaction 1

Gly-1 requires ATP and is not reversible

Bypass using a simple hydrolytic reaction

Reaction 3

Gly-3 requires ATP and is not reversible

Bypass using a simple hydrolytic reaction

Reaction 10

Gly-10 (PEP to pyruvate) is bypassed by a two reaction sequence requiring both ATP and GTP

Gluconeogenesis vs Glycolysis Reaction 1

Gluconeogenesis vs Glycolysis Reaction 3

Gluconeogenesis vs Glycolysis Reaction 10

What are the two type of regulation?

spatial

temporal

Spatial Regulation:

both pathways can occur simultaneously in different parts of the body

Temporal Regulation:

cannot do both reactions at the same time in the same part of the body

In relation what happens to the types of regulation?

stimulate one, inhibit the other

What are the key places of allosteric regulation during glycolysis?

hexokinase

phosphofructokinase-1

pyruvate kinase

What are the key places of allosteric regulation during gluconeogenesis?

fructose-1,6-biphosphatase

pyruvate carboxylase

AMP is an ______ for glycolysis and an _____ for gluconeogenesis

allosteric activator

allosteric inhibiter

High energy molecule

inhibit glycolysis

activate gluconeogenesis

low energy molecules

inhibit gluconeogenesis

activate glycolysis

ATP is both a substrate and an allosteric inhibitor of

PFK-2

At low [ATP]

it binds to the active site, glycolysis goes

At high [ATP]

inhibits glycolysis

The most common 3 carbon precursor for gluconeogenesis is

pyruvate

What is the name of the enzyme responsible for the oxidation / reduction reaction in ethanolic fermentation?

Alcohol dehydrogenase

The new output of ATP from glycolysis followed by fermentation is ______, and the NADH yield from glycolysis followed but fermentation is _________.

2 ; 0

During strenuous exercise, you may notice that your muscles burn. Which of the following statements best explains this phenomenon?

Without oxygen, pyruvate is being converted to lactic acid

The process by which lactase is removed from muscle tissue and returned to the liver to produce glucose is called

Gluconeogenesis

Which of the following is NOT an allosteric inhibitor of an enzyme in glycolysis.

Fructose-2,6-biphosphate