Lecture 17

Question 1

what is the RER for a normal mixed diet

Answer 1

= 0.82 = 60% fats + 40% CHO

Question 2

situations where gas exhange does not reflect RQ

Answer 2

1- exhaustive exercise
2- incremental (non stready state) exercise 
3- hyperventilaton
4- excess post exercise V02 uptake 
5- prolonged exercise

Question 3

ATP functions

Answer 3

• ATP is constantly breaking down to supply us with energy

- ATP is constantly being rebuilt using energy from fats & CHO & protein

Question 4

ATP stucture

Answer 4

High energy bonds = unstable & can be broken in the presence of water
adenine + ribose = adenosine

Question 5

ATP hydrolysis yields energy

Answer 5

Energy is released when the terminal phosphate is cleaved from the molecule (hydrolysis).
= Adenosine diphosphate (ADP) + Pi + 7.3 kcal.mol energy

Question 6

when energy is needed in the body

Answer 6

• ATP is broken down to ADP + Pi + energy
• Energy is used for building/anabolism of other products as well as to perform work.
• ADP + Pi are reformed back to ATP using energy from the breakdown/catabolism of foodstuffs.
• ATP is continually recycled from intracellular ADP, Pi, plus energy released from stored macronutrients.

Question 7

How can ATP created with and without oxygen

Answer 7

• can be created with energy from foods (CHO + fats) + oxygen in the mitocondria - aerobic metabolism: serobic metabolism
  OR without oxygen: With energy from food, (CHO) but without oxygen in the Cytosol / cytoplasm = Anaerobic metabolism

Question 8

Phosphocreatine

Answer 8

= immediate energy

Phosphocreatine is an intracellular high energy phosphate molecule that stores energy within the muscle.

Question 9

PCr and ATP

Answer 9

• stores energy

- supplies energy to resynthesis ATP

Question 10

Phosphocreatine

Answer 10

• Cells store approx 4-6 times more PCr than ATP (320-600g)

- Thus PCr serves as a ‘reservoir’ of high energy phosphate bonds.

Question 11

PCr allows for the most rapid ATP resynthesis for max activity because

Answer 11

• PCr located in near the contractile muscle
• PCr hydrolysis liberates energy without a long series of reactions
• PCr does not depend on a supply of O2 = Anaerobic

Question 12

How is PCr rebuilt back? when run out

Answer 12

ATP resynthesis via phosphocreatine
- The reaction is reversible in that a Pi + creatine (Cr) can rejoin to form PCr again - energy is needed!
- The energy needed to ‘glue’ PCr back together comes form energy released during the breakdown of ATP.
Energy from fats and CHO constantly remake ATP)
- Resynthesis occurs during recovery from exercise

Question 13

how to test phosphocreatine - tests must be maximal and less than 6 second duration

Answer 13

• stair sprinting test
• jump and reach
• broad jump
  physiological tests:
• measurement of the intramuscular ATP/PCr concentrations;
• measurement of depletion rates of ATP/PCr pool

Question 14

Phosphorylation

Answer 14

Phosphorylation occurs when an inorganic phosphate (Pi) is coupled/attached to ADP

Question 15

The energy needed to allow phosphorylation to occur is

Answer 15

1- the breakdown of PCr

2- food sources