Metabolism 1

Question 1

What is the The First Law of Thermodynamics?

Answer 1

Energy is neither created nor destroyed, it is only altered in form.

Question 2

What is Adenosine Triphosphate?

Answer 2

aka… ATP

• Stores energy transferred from the breakdown of carbohydrates, fats and proteins.
• A necessity for proper cellular functioning.

Question 3

What is ATP Hydrolysis?
What are its Products?

Answer 3

• Addition of water (hydro) to breakdown (lyse) ATP
• Energy released during this reaction

Products:

• ADP
• Pi
• H+
• Energy

Question 4

How do we transfer energy from food
nutrients to ATP?

Answer 4

Metabolic Pathways
1. ATP-CP ( aka PCr aka the phosphagen system)
2. Phosphorylation via glycolytic pathways in the cytosol (CHO)
3. Oxidative Phosphorylation in the mitochondria

Question 5

ATP-CP
What, Where, When, Who?

5

Answer 5

• Anaerobic
• Location: cytosol
• ATP Availability: immediate
• ATP sustainability: ~15-30s
• Enzyme: creatine kinase

Question 6

ATP-CP

What is happening to creatine at rest?

Answer 6

Creatine (Cr) is phosphorylated into creatine phosphate (CP) in the muscle cells.

CP is replenished to concentrations approximately 5 times that of ATP.

Question 7

ATP-CP

What is happening to creatine during excersize?

Answer 7

As exercise begins, there’s an increase in the concentration of adenosine diphosphate (ADP), which is a byproduct of ATP breakdown.

This increase in ADP concentration triggers the hydrolysis of CP back into Cr and phosphate (Pi).

Consequently, the concentration of CP decreases.

Question 8

ATP-CP

What happenes to the concentration of ATP, ADP and CP during the onset of excersize?

Answer 8

[ADP] increase
[CP] decrease
[ATP] stable

Question 9

How is ATP-CP limited?

Answer 9

Pathway is limited by concentration of CP in the myofibre

Question 10

Glycolosis
What, Where, When, How?

Answer 10

• Anaerobic
• Location: cytosol
• ATP Availability: quick (when substrates and enzymes are available)
• ATP Sustainability: ~2 minutes
• Important Enzymes: hexokinase, phosphofructokinase (PFK

Question 11

What is the net ATP gain from glycolosis?

Answer 11

Net ATP Gain: 2

Question 12

Reactants and Products of Glycolosis:

Answer 12

Question 13

When is Glycolysis used?

Answer 13

• 10 enzymatic reactions
• Contributes a significant fraction of ATP when exercise exceeds ~70% of the maximal rate of ATP breakdown

Question 14

Glycolosis Simplified

Answer 14

Question 15

After Glycolosis, which 2 pathways can Pyruvate take?

Answer 15

1. Converted to lactate (producing little energy)

• Substrate-level oxidation
• Does not require oxygen - Anaerobic Glycolysis

2. Continue through the Krebs Cycle and onto OXPHOS

• Produces a lot of energy
• Requires oxygen - Aerobic Glycolysis

Question 16

What happens during Anaerobic Glycolysis?

Answer 16

• Hydrogen atoms derived from NADH + H are transferred to pyruvate to form lactate
• This replenishes NAD+ for glycolysis