Thompson 4

Question 0

During fasting, the liver must increase _____ levels, and thus undergoes _____.

Answer 0

blood glucose, gluconeogenesis

Question 1

After a meal, ____ (ultimately) provides carbon for the synthesis of _______. This is a primary mechanism of energy _______.

Answer 1

glycolysis, fatty acid, storage

KEY CONCEPT: the liver works to maintain BLOOD GLUCOSE levels, not ATP levels.

Question 2

In gluconeogenesis, the ______ converts _______ precursors into glucose.

Answer 2

liver, NON-carbohydrate (lactate, glycerol, amino acids..)

Question 3

Gluconeogenesis requires how many ATP equivalents?

Answer 3

6.

Question 4

Lactate dehydrogenase converts ____ into ____.

Answer 4

Pyruvate, lactate (and reverse)

Question 5

Alanine aminotransferase interconverts which two molecules?

Answer 5

Alanine, pyruvate

Question 6

The irreversible conversion of pyruvate to oxaloacetate requires the enzyme ____ and the cofactor _____.

Answer 6

Pyruvate carboxylase, biotin (also requires 2 ATP per glucose synthesized or 1 per pyruvate)

Question 7

There are two ways to convert pyruvate to PEP. Pyruvate is transferred to the ____ in both pathways. _____ is used to transfer reducing eqs back to the cytosol where _____ catalyzes the final reaction to PEP. If ____ is the precursor to pyruvate, _____ catalyzes the final reaction and PEP is transported to the cytosol.

Answer 7

mitochondria, malate (NADH), cytosolic PEP carboxykinase, lactate, mitochondrial PEP carboxykinase

Question 8

Gluconeogenesis occurs primarily in the _____ because it is the only tissue with _____, which secretes free glucose into the blood.

Answer 8

liver, G6 phosphatase

Question 9

In which direction does acetyl CoA regulate gluconeogenesis? Why?

Answer 9

Upregulates conversion of pyruvate to oxaloacetate (promotes gluconeogenesis) because a high level of acetyl CoA means there is a high amount of TCA activity and ATP production (or that a lot of catabolism just took place and macromolecules have been broken down into acetyl CoA), and thus glycolysis is not needed because the body is likely in a fasting state now. Blood glucose needs to be raised, so the liver must release glucose, requiring gluconeogenesis.

Question 10

Excessive alcohol consumption creates an excess of ______ which diverts precursors of _____ to other pathways, thereby inhibiting it.

Answer 10

NADH, gluconeogenesis (pyruvate gets reduced to lactate and oxaloacetate gets reduced to malate)

Question 11

Two compounds can be converted to pyruvate. What are they and what enzymes do they use? Pyruvate is converted to OAA using which enzyme and cofactor?

Answer 11

Lactate, lactate dehydrogenase (uses NAD+); alanine, alanine aminotransferase; pyruvate carboxylase, biotin (and CO2 and ATP)

Question 12

The elongation bond in glycogen is ____, and the branching bond is _____.

Answer 12

Alpha 1-4 glycosidic, alpha 1-6 glycosidic

Question 13

There is only one glucose monomer in glycogen with a reducing end that is not attached to another glucose. What is it attached to?

Answer 13

Glycogenin

Question 14

Glucose to UDP-glucose requires how many ATP equivalents?

Answer 14

Two. 1 in G -> G6P, and 1 in the form of UTP (G1P -> UDP-G)

G6P is converted to G1P by mutase. UTP adds only 1 phosphate (G1P already has one) leaving PPi.