Ch. 2 Bioenergetics Flashcards
When do nonelite marathon runners normally have “hit the wall” when competing
Around mile 20-22
Why do runners “hit the wall”
They run out of glycogen energy
Most runners store around… calories of glycogen
2k-2.2k
Fuel sources from which we make energy
(adenosine triphosphate [ATP])
Energy substrates
Example of energy substrates
Carbohydrate, fat, protein
Process of converting substrates into energy at CELLULAR LEVEL
Bioenergetics
Chemical reactions in the body
Metabolism
Words describing breaking down & building up
Catabolic (break down)
Anabolic (build up)
How can you calculate energy released from a biological reaction
Heat produced
What are the units for energy in humans?
Kcal (kilocalorie)
Energy from chemical bonds in food stored
in high-energy compound
ATP
How many kcal stored in the body?
2,500 kcal stored in body
Where is extra glycogen stored in?
Liver & muscle
Necessary carbohydrates that convert to glucose size
4.1 kcal/g
Efficient fat kilocalories stored in body
– 9.4 kcal/g
– +70,000 kcal stored in body
Substrate for prolonged, less intense exercise
– Fat
Must be broken down from triglyceride to free fatty
acids (FFAs) and glycerol
– Only FFAs are used to make ATP
Energy substrate during starvation (protein)
-4.1 kcal/g
The process of converting non-carb substrates into glucose is known as
Gluconeogenesis
2 factors controlling rate of energy production
-availability of primary substrate
-Enzyme activity
Enzymes are
Protein molecules
Increase in enzyme activity =
Increase in product
Three ATP synthesis pathways
- ATP-PCr system (anaerobic metabolism)
- Glycolysis (anaerobic metabolism)
- Oxidative system (aerobic metabolism)
What catalyzes PCr?
Creatine Kinase
ATP yield for glycolytic system involving glucose and glycogen
Glucose 2
Glycogen 3
The net ATP yield from aerobic metabolism of glucose is … ATP
32
One molecule of 16 carbon FFA yields … acetyl-CoA
8
