LG 1.8 - Biochem Muscle Metabolism

Question 1

When is Anaerobic Metabolism useful?

Answer 1

Although anaerobic metabolism is inefficient,
sometime you just feel like moving fast.

Anaerobic metabolism is useful only for extremely short time frames.

anaerobic metabolism can save lives so that later the body can find opportunities to replenish its depleted energy stores.

Question 2

Aerobic metabolism

ends with the production of _______

Answer 2

Pyruvate

Question 3

Anaerobic metabolism

requires the additional step of reducing pyruvate to lactate. WHY??!

Answer 3

Dehydrogenase enzymes interconvert NAD+ and NADH
Need the energy.

NAD+ is an essential substrate of glycolysis.. The NAD+ produced by lactate dehydrogenase exactly balances the NADH produced by glycolysis

Question 4

What does Anaerobic Metabolism use as fuel?

Answer 4

Glucose

Question 5

What does aerobic metabolism begin with?

Answer 5

Acetyl CoA

Question 6

How many ATP are yielded by Aerobic Metabolism

Answer 6

one molecule of glucose yields at most 38 ATP due to variable mechanical loses the net production per glucose molecule is ~30 ATP.

Question 7

How many ATP and NADH are yielded by Anaerobic Metabolism?

Answer 7

yields only 2 ATP and 2 NADH

Question 8

What does gluconeogenesis use as precursors when created glucose de novo in the liver?

Answer 8

liver at some expense in ATP uses precursors that have at least 3 carbons such as: lactate, pyruvate, alanine, and glyerol

Question 9

The most sensitive signals of low energy within the cell is ___.

Answer 9

AMP

Question 10

Which adenylate will have the greatest change in concentration relative to its initial concentration (ATP, ADP, or AMP?

Answer 10

AMP the most sensitive signals of low energy with in a cell.

AMP is normally at such low concentration in the cell
that even a small change in absolute concentration may lead to a 10 fold or 100 fold in relative concentration.

Question 11

Creatine diet supplement uses

Answer 11

1. increase muscle mass if used after exercise.
2. have some beneficial effects on muscle mass for elderly if used in combination with other nutrients
3. damage the liver and kidney if taken in excess.

Question 12

Creatine Phosphate vs. ATP

Answer 12

Creatine phosphate is simpler, more soluble, and less expensive than ATP.
A higher cellular concentration of creatine phosphate is possible, because it can diffuse rapidly through a cell.

Question 13

Where is creatinine cycled out and how is it created?

Answer 13

Creatine spontaneously cyclizes at a slow rate to form creatinine which serves no biological function and is eliminated by the kidneys

Question 14

What enzyme regulates degradation of glycogen?

Answer 14

Glycogen phosphorylase

Question 15

What is the Creatine Shuttle Hypothesis

Answer 15

Creatine not only provides a buffer for high energy phosphate bonds, but it is a transporter that carries high energy phosphoryl groups from the source of ATP production (mitochondria), to the location of ATP hydrolysis (myosin)

Question 16

Diagram the Creatine Shuttle

Answer 16

See slide 12

Question 17

See Slide 2

Answer 17

See Slide 2

Question 18

See Slide 3

Answer 18

See Slide 2

Question 19

Name the muscle fiber types color, mitocondria, myoglobin, etc

Answer 19

See slide 5

Question 20

Explain how, during vigorous exercise, active muscle meets its extreme need for ATP and summarize each of the various relevant mechanisms

Answer 20

See Slide 9

Question 21

What enzyme converts Glucose to Glycogen?

Answer 21

Glycogen synthase

Question 22

How does glycogen phosphorylase work?

Answer 22

Breaks glucose monomers off of glycogen polymers

Uses the energy of glycosidic bond to form a high energy phosphate bond. See slide 12.

Question 23

Is glycogen phosphorylase more regulated by AMP or ATP?

Answer 23

AMP.

AMP is a more sensitive indicator of cellular energy than is ADP or ATP

Question 24

Will high AMP concentration stimulate or inhibit glycogen phosphorylase?
Will high ATP concentration stimulate or inhibit glycogen phosphorylase

Answer 24

Energy production is generally signaled by low energy compounds.
Energy storage is generally signaled by high energy compoudns.

Question 25

Where is Glycogen Phosphorylase Activity?

Answer 25

In the liver. Liver cells export glucose monomers in time of need-gluconeogenesis

Question 26

What are the 3 forms of glucose?

Answer 26

G1P, G6P, and F6P

Question 27

What is Von Gierke disease?

What can it lead to?

Answer 27

Type I glycogen storage disease. Results from mutations that inactivate glucose-6-phosphatase.

It can lead to hepatomegaly, accumulation of fat and glycogen in the liver

Question 28

What is the function of Myoglobin and Hemoglobin? What are the differences between myoglobin and hemoglobin?

Answer 28

Oxygen is transported and stored bound heme groups on proteins, Myoglobin and hemoglobin

Myoglobin globular protein monomer found in muscle

Hemoglobin globular protein tetramer found in blood

See Slide 13 for graph

Question 29

What is excess post-exercise oxygen consumption (EPOC) or oxygen debt?

Answer 29

Represents the extra amount of oxygen that must be taken in after strenuous exercise to achieve metabolic homeostasis.

Question 30

Why does hemoglobin bind oxygen less tight than myoglobin inside the muscle tissue?

Answer 30

• Hemeglobin drops oxygen off in the tissues and therefore does not need to bind oxygen as tightly in the tissue.
• Myoglobin is holding onto that oxygen inside muscle cells and saving it for a time of need, therefore can hold it tighter until necessary to release

Question 31

In muscle, what enzyme converts Pyruvate–>lactate?

Answer 31

Lactate dehydrogenase

Question 32

In the liver, what enzyme converts Lactate–>Pyruvate?

Answer 32

Lactate dehydrogenase