?

Biochemistry

Free Version

Upgrade subject to access all content

Moderate

Glucose-Alanine and Cori Cycles

BIOCHM-J9NJRS

During intense exercise, your muscles obtain fuel by burning glycogen and also proteins and their amino acids. The carbon skeleton products of these reactions are salvaged and recycled or, if potentially toxic, converted to an excretable form. This is accomplished by two cycles, the glucose-alanine cycle and the Cori (or lactic acid) cycle. The simplified schematic below illustrates the interweaving of these two pathways.

Arya Bima. "Cori & Alanine Cycle." Wikimedia Commons. N.p., 27 Mar. 2011. Web. 05 Sept. 2016.

After reviewing the two pathways and noting the unnamed "body/tissue locations" marked by boxes A, B, and C, and the unnamed biochemical reactions or pathways numbered 1-4, identify ALL of the following statements which are TRUE.

Select ALL that apply.

A

The pathway/reaction indicated by #1 is gluconeogenesis and #2 is glycolysis.

B

Lactate and alanine, both generated by the Cori cycle, are transported in the blood (indicated by Box B).

C

The most common source of lactic acid in actively respiring muscle is the anaerobic breakdown of glycogen by glycogenolysis and glycolysis.

D

Alanine is a carrier of potentially toxic​ ammonia in the glucose-alanine cycle.

E

The ATP generated by glycolysis in muscle tissue can be used to power gluconeogenesis.

F

In both the Cori cycle and the glucose-alanine cycle, the final carbon skeletons are salvaged by conversion back to glucose via gluconeogenesis in the liver.

G

In the glucose-alanine cycle, NADH is conserved relative to the Cori cycle, making it available for mitochondrial oxidation and ATP synthesis via the electron transport chain.

H

The reaction indicated by #1 is a transamination, and a common amino group donor is the amino acid glutamate.