Carbohydrate Metabolism [Glycogenesis, Glycogenolysis, The Cori Cycle, and The Pentose Phosphate Pathway]

Glycogen

Branched polymeric form of glucose

Glycogen

Storage form of carbohydrates in humans

Glycolysis

In muscle, it is the source of glucose for (?)

Liver

In (?) tissue, it is the source of glucose required to maintain normal blood glucose levels

A

Identify the step in Glycogenesis

1.) Starting material is glucose 6-phosphate (available from the first step of glycolysis)

A.) Step 1: Formation of glucose 1-phosphate

B.) Step 2: Formation of UDP-glucose

A

Identify the step in Glycogenesis

2.) Enzyme phosphoglucomutase effects the change from a 6-phosphate to a 1-phosphate

A.) Step 1: Formation of glucose 1-phosphate

B.) Step 2: Formation of UDP-glucose

B

Identify the step in Glycogenesis

1.) High-energy compound UTP (uridine triphosphate) activates glucose 1-phosphate to form uridine diphosphate glucose (UDP-glucose)

A.) Step 1: Formation of glucose 1-phosphate

B.) Step 2: Formation of UDP-glucose

UDP

Glucose transfer to a glycogen chain

1.) Glucose unit of UDP-glucose is attached to the end of a glycogen chain and (?) is produced

Pentose Phosphate Pathway

This is the pathway in which glucose 6-phosphate is used to produce NADPH, ribose 5-phosphate (a pentose phosphate), and numerous other sugar phosphates.

UTP; ADP

Glucose transfer to a glycogen chain

2.) UDP reacts with ATP to form (?) and (?)

Glycogenolysis

Breakdown of glycogen to glucose

Glycogen

Glycogenolysis

Once the blood glucose levels are low, it will utilize the stored (?) to replenish it.

2

How many steps are there in Glycogenolysis?

Glycolysis

Pentose Phosphate Pathway

When ATP demand is high, the pathway continues to its end products, which enter (?).

B

Two-step process of Glycogenolysis

Phosphoglucomutase catalyzes the isomerization process whereby the phosphate group of glucose 1-phosphate is moved to the carbon 6 position (reverse of the first step of glycogenesis)

A.) Phosphorylation of a glucose unit

B.) Glucose 1-phosphate isomerization

Cori Cycle

The cycle of lactate to glucose between the muscle and liver

pyruvate

Cori Cycle

Gluconeogenesis uses lactate as a source of (?)

A

Two-step process of Glycogenolysis

Glycogen phosphorylase effects the removal of an end glucose unit from a glycogen molecule as glucose 1- phosphate

A.) Phosphorylation of a glucose unit

B.) Glucose 1-phosphate isomerization

Liver

Cori Cycle

Lactate is formed during strenuous exercise. It diffuses from muscle cells into the bloodstream and is transported to the (?)

2 ATP

Glucose transfer to a glycogen chain

3.) Adding one glucose unit to a glycogen chain requires the investment of (?) molecules

Pyruvate; Lactate; Pyruvate; Glucose

Cori Cycle

Glucose → (?) → (?) [then goes to liver] → (?) → Glucose-6-Phospate → (?) → Goes back to the cell to perform glycolysis

Lactate dehydrogenase

Cori Cycle

Which enzyme converts lactate to pyruvate in the liver?

recycled

Pentose Phosphate Pathway

When NADPH demand is high, intermediates are (?) to glucose 6-phosphate (the start of the pathway), and further NADPH is produced.

It helps generate ribose 5- phosphate for nucleic acid and coenzyme production

Muscles

Cori Cycle

Pyruvate is then converted to glucose via gluconeogenesis. The glucose enters the bloodstream and is transported to the (?)

Oxidative; Non-Oxidative

What are the two stages of Pentose Phosphate Pathway?

Oxidative stage

Pentose Phosphate Pathway

Identify the stage:

Involves three steps through which glucose 6-phosphate is converted to ribulose 5-phosphate and CO2

Non-Oxidative stage

Pentose Phosphate Pathway

Identify the stage:

In the first step, ribulose 5-phosphate (a ketose) is isomerized to ribose 5-phosphate (an aldose)