Chapter 2: Fuel for Exercise: Bioenergetics and Muscle Metabolism
What is ATP?
adenosine triphosphate (high-energy compound)
substrates:
bioenergetics:
metabolism:
chemical reaction in the body
How is ATP of importance in metabolism?
because it is the useable storage form of energy we derive from food
What is the primary substrate used to provide energy at rest?
50% carbohydrates and 50% fats
What is the primary substrate used to provide energy during high-intensity exercise?
the use of more carbohydrates
Exercise that is short uses:
more carbohydrates
Exercise that is long uses:
carbohydrate, more fat
All dietary carbohydrate is converted to what?
glucose
What is the role of PCr in energy production?
What is the relationship between muscle ATP and PCr during sprint exercise?
What are the essential characteristics of the ATP-PCr system?
When ATP levels decrease:
ADP increases & CK activity increases
When ATP levels increase:
CK activity decreases
What are the essential characteristics of the glycolytic system?
Cons of the glycolytic system:
Pros of the glycolytic system:
What are the essential characteristics of the oxidative system?
What are the stages of oxidation of carbohydrate?
Characteristics of oxidation of carbohydrate:
Electron Transport Chain:
Krebs Cycle:
Why are the ATP-PCr and glycolytic energy systems considered anaerobic?
because they contribute energy during short-burst activities lasting up to 2 minutes and during the early minute of longer higher-intensity exercise
What role does oxygen play in the process of aerobic metabolism?
helps to breakdown substrates which intern provides more energy
What are the by-products of energy production from the ATP-PCr system?
1mol ATP/ 1mol PCr
What are the by-product of energy production from the Glycolysis system?
2-3mol ATP/ 1 mol substrate (glucose/glycogen)
What are the by-products of energy production from the Oxidative system?
32-33mol ATP/ 1 glucose; 100+ATP/ 1 FFA
Characteristics of oxidation of fat:
What is beta-oxidation of fat?
Characteristics of oxidation of fat:
What are all 3 energy systems stimulated by?
the presence of ADP
What will be the major fuel source for carbohydrates and skeletal muscle and why?
glycogen because it is right there in the cytosol
T or F: The transition from one fuel source to another does not depend on the previous one.
true
What is lactic acid and why is it important?
What are the interactions among energy systems?
How do type I muscle fibers differ from type II fibers in their respective oxidative capacities? What accounts for those differences?
What key message is depicted in this figure?
the presence of an enzyme lowers the activation energy required to produce ATP from phosphocreatine
The combination of his sprinting speed and powerful jumping abilities has made Luis a solid long jumper. Luis' body maintains his ATP levels during the long jump via the _____________ system.
ATP-PCr
The system that is maintaining Luis' ATP levels produces ATP without the aid of ____________, although it is always present.
oxygen
This system also uses the molecule phosphocreatine to rebuild ATP and maintain a relatively constant supply. The _________ enzyme acts on PCr to separate Pi from creatine. The energy released can then be used to couple Pi to an ADP molecule, forming ATP.
creatine kinase
Suppose that the next season, Luis adds the 800-meter run, an event that average high schoolers run in a little over 2 minutes. Think about Luis’ prior training and his energy systems. Initially, he will find his prior training to be _________ for the event.
inadequate
The first few seconds of the 800-meter race will likely feel good to Luis, but he will find that the length of the event will tax his ___________.
glycolytic system
Before Luis fully trains for the 800-meter race, he’ll probably find that he’s a _________ starter and a _________ finisher.
strong/weak
Glycogen is stored in the _________ until needed.
liver or muscle
T or F: The glycolytic system has a tremendous energy-yielding capacity, so it is the primary method of energy production during endurance events.
false
T or F: A healthy body uses little protein during rest and exercise.
true
Energy for muscular activity and cellular operations is primarily derived from:
carbohydrate, fat, and protein
T or F: When phosphorylation occurs without the aid of oxygen, it is called aerobic metabolism.
false
NADH molecules, formed in the _____________, cannot directly enter the mitochondria.
sarcoplasm