Glycogenesis & Glycogenolysis (Exam 2)

Question 1

Between the liver and muscle tissue, which has a larger capacity for glycogen storage?

Answer 1

The muscle tissue

Question 2

Between the liver and muscle tissue, which stores more glycogen?

Answer 2

The LIVER - 5.0% glycogen of tissue weight compared to 0.7% in the liver (this does vary based on the individual)

Question 3

What is the role of glycogen within the muscle tissue?

Answer 3

Muscle glycogen acts as a fuel reserve for ATP within the muscle, and is NOT important of the maintenance of BG levels

–Muscle glycogen levels vary MUCH less in response to food intake as compared to liver glycogen

Question 4

What is the role of glycogen within the liver tissue?

Answer 4

It serves as a glucose reserve for maintaining BG levels, between meals, short-fasting, and overnight.

–VARIES WITH FOOD INTAKE, with a high level after a meal, and decreasing slowly as it is mobilized to maintain BG levels, until the next meal is consumed.

Question 5

(TRUE/FALSE)

Muscle glycogen is used for between meals, and to a greater extent during the nocturnal fast.

Answer 5

FALSE

LIVER GLYCOGEN

Question 6

What mobilizes muscle glycogen to form ATP?

Answer 6

Exercise

Question 7

Red muscles cells

Answer 7

Supplied with rich supply of blood, which have a large amount of MYOGLOBIN and are packed with MITOCHONDRIA

Question 8

White muscle cells

Answer 8

Poor supply of blood and oxygen and fewer mitochondria

Question 9

What determines the yield of ATP and the fate of carbons from glycogen?

Answer 9

The muscle cell type, if it’s ‘white’ or ‘red’

Question 10

Where does glycogen in ‘red muscle’ go?

Answer 10

The glycogen will be converted to glucose and then to pyruvate. Then pyruvate is completely oxidized to CO2, H2O, and ATP (due to O2 and MITO)

Question 11

Where does glycogen in ‘white muscle’ go?

Answer 11

Glycogen is converted to LACTATE primarily (which will go to the Cori Cycle, in the liver)

The Krebs Cycle is not utilized as much due to the limited amount of mitochondria

Question 12

In which color muscle cell does glycogen provide energy for long-sustained activities?

Answer 12

RED muscle cells (requires more ATP)

Question 13

In which color muscle cell does glycogen provide energy for short periods of maximal activity?

Answer 13

WHITE muscle cells (as glycogen is mobilized rapidly)

Question 14

(TRUE/FALSE)

In humans, most skeletal muscles are a mixture of red and white fibers to provide for both rapid and sustained muscle activity.

Answer 14

TRUE

Question 15

Which color muscle has more capacity for glycogenolysis and glycolysis than red muscle fibers?

Answer 15

WHITE MUSCLE CELLS

Question 16

What is glycogen comprised of?

Answer 16

Many glucose molecules (aka glycosyl residues)

Question 17

Through what type of bond are glycosyl residues (glycogen) linked together by?

Answer 17

Alpha-1.4 glyosidic linkages

Question 18

Through what type of bond does branching occur?

Answer 18

Alpha-1,6 glycosidic linkages

Question 19

What is the purpose of branching?

Answer 19

The branching allows a much HIGHER CAPACITY OF STORAGE versus having one long strand. It also increases SURFACE AREA so when its time to start breaking down glycogen, the enzymes are able to have more targets