Physiology of Exercise Chapter 2


Terms in this set (...)

What do we make from substrates?
Energy aka ATP
The process of converting substrates to energy is what?
Where is bioenergetics performed?
At the cellular level
What is 1kcal equal to?
1 dietary calorie
What are the 3 types of substrates?
Carbs, fats, and proteins
What are the 2 primary substrates used?
Carbs and fats
What 4 components make up substrates?
1. Carbon
2. Hydrogen
3. Oxygen
4. Nitrogen
In short exercise, what substrates is mostly used?
In long exercise, what substrate is mostly used?
How many kcal/g is carbohydrates?
What is carbohydrates converted to?
What is the primary ATP substrate for the muscles and brain?
What is Glycogen converted back into _________ to make more ATP.
Where and what is extra glucose stored as?
Stored as glycogen in liver and muscles.
How many kcal/g is in fat?
What energy substrate is for prolonged, less intense exercise?
Which substrate has a high net ATP yield but slow ATP production?
What substrate must be broken down into free fatty acids (FFAs) and glycerol?
Why is carbohydrate replenishment so important?
Because more fat is stored in the body than carbohydrates
How many kcal/g are in proteins?
Which energy substrate is used during starvation?
Protein is converted into FFAs through what process?
What substrate uses lipogenesis for conversion to FFAs?
Protein is converted into glucose through what process?
What substrate uses gluconeogenesis to convert into glucose?
Mass Action Effect
If there's more available substrate, then cells rely more on that substrate for energy
Do not start chemical reactions; facilitate breakdown and lower the activation energy for a chemical reaction
Breaks ATP down into ADP+ Pi+ energy
Suffix: ase=
More enzyme activity means:
More product
Breakdown of ATP to release energy formula:
ATP+ water+ ATPase--> ADP + Pi+ energy
Synthesis of ATP from by-products formula:
ADP + Pi + energy----> ATP; can occur with or without O2
What process allows for the synthesis of ATP
Rate-limiting enzyme
Slows the overall reaction and prevents runaway reaction
3 ATP Synthesis Pathways:
1. ATP-PCr
2. Glycolytic
3. Oxidative
ATP- PCr System
Anaerobic, substrate level metabolism; 3-15 sec. max; Body breaks down PCr to make Creatine & Pi & energy; uses energy to synthesize ATP combine Pi and used ADP.
ATP-PCr is catalyzed by what enzyme?
Creatine Kinase
When ATP levels are up:
CK levels down
When ATP levels are down:
ADP & CK levels are up
Glycolytic System
Anaerobic; yield 2-3 ATP/substrate; lasts 15s to 2 min; breakdown of glucose via glycolysis
Breakdown of glucose; anaerobic or aerobic
Process by which glycogen is synthesized from glucose to be stored in the liver or muscle
Process by which glycogen is broken down into glucose-1phosphate to be used for Energy production
Where is 99% of glucose found?
T/F: Glucose used the majority of the time
True, but costs 1 ATP
ATP yield of Glycolysis
Glucose- 2
By-product of Glycolysis with O2
Pyruvic acid
By-product of Glycolysis without O2
Lactic Acid
Cons of Glycolysis
1. Low ATP yield
2. Lack of O2 causes lactic acid, which impairs muscle contraction
Pros of Glycolysis
1. Allows muscles to contract when O2 is limited
Rate-limiting Enzyme of the Glycolytic System
Oxidative System
Aerobic; 32-33 ATP/ glucose, 100+ ATP/FFA; lasts a long time; Occurs in the mitochondria, not the cytoplasm
3 Stages of Oxidation of Carbs
1. Glycolysis
2. Krebs Cycle
3. Electron Transport Chain
Occurs with or without o2, but yields the same ATP; converts Pyruvic Acid to acetyl-CoA
1 mole of glucose produces how many acetyl-CoA?
Krebs Cycle
Converts 2 acetyl-CoA to 2 GTP to 2 ATP; also produces NADH, FADH, H+
Too many H+ in a cell=
Too acidic
Electron Transport Chain
NADH, FADH molecules carry H+ electrons to ETC; H+, electrons travel down the chain; H+ combine with O2 to form H2O, which helps form ATP; 2.5 ATP/ NADH, 1.5 ATP/FADH
Oxidation of Carb Energy Yield
1 glucose= 32 ATP
1 glycogen= 33 ATP

Glycolysis= 2-3 ATP
GTP(Krebs Cycle)= 2 ATP
10 NADH= 25 ATP
Oxidation of Fat
Uses Triglycerides as a major fat energy source broken down into 1 glycerol & 3 FFAs; yields 3-4 times more ATP than glucose but slower
Beta-Oxidation of Fat
Converts FFAs to acetyl-CoA before Krebs Cycle; requires 2 ATP upfront; requires more 02, but more ATP later
Oxidation of Protein
Early used as substrate except during starvation; can be converted to glucose and acetyl-CoA
Control of Oxidative Phosphorylation
Negative feedback regulates Krebs Cycle; Isocitrate dehydrogenase- rate-limiting-enzyme; regulates etc, inhibited by ATP, activated by ADP
Interaction Among Systems
All 3 systems interact, not all doing 100%; cooperation during transition periods
3 Factors Determining Oxidative Capacity of Muscle:
1. Enzyme activity
2. Fiber type composition, endurance training
3. O2 availability vs. O2 need
Type 1 Fibers:
More mitochondria; high enzyme concentrations
Endurance Training
Enhances oxidative capacity of Type 2 fibers; develops more and bigger mitochondria
As intensity goes up,
So does ATP demand
O2 storage limited
use it or lose it
O2 use in muscle formula:
O2 levels leaving lungs- O2 levels enter lungs