Module 1: Introduction to exercise physiology and bioenergetics

Question 1

Describe the steps within the research process:

Answer 1

1. Observation
2. Hypothesis
3. Experiment
4. Results and Interpretation
5. Accept or reject hypothesis

Question 2

What is the difference between a longitudinal vs cross sectional research design?

Answer 2

Longitudinal research analyzes the same subjects over a period of time. On the other hand, cross sectional studies analyze and compare data between groups in a population.

Question 3

What is the difference between an acute vs chronic exercise response?

Answer 3

An acute exercise response is a change that results from a single session of exercise. Meanwhile, a chronic exercise response is change that results from repeated bouts of exercise overtime.

Question 4

What is a confounding variable? Provide examples:

Answer 4

A variable which is connected to both the independent and dependent variables in a study, which may detriment the legitimacy of the relationship found in a study.

i.e., a study analyzing obesity and heart disease may be confounded by age, diet, and smoking status.

Question 5

What does the x-axis represent when it comes to a graph?

Answer 5

Independent variable.

Question 6

What does the y-axis represent when it comes to a graph?

Answer 6

Dependent variable.

Question 7

What is the concept of bioenergetics?

Answer 7

Study of energy transfer via chemical reactions in living tissues.

Utilize foods as fuel (carbohydrates, fats, proteins), broken down into ATP (storage form of energy), energy is released to perform physiological functions and most is lost to heat.

Question 8

What are the four categories of energy?

Answer 8

Heat (unusable), chemical (breakdown of ATP), mechanical (SKM contractions), electrical (nerve impulses)

Question 9

What is the first law of energy transfer (thermodynamics)?

Answer 9

Energy can neither be created or destroyed, only transferred from one form to another.

Delta E = usable (free) + nonusable (heat)
Majority is lost as heat

Question 10

What is the most efficient fuel with regards to energy transfer?

Answer 10

Glucose - 40% of it is deemed usable.

Question 11

What is the basic structure of Adenosine Triphosphate (ATP)?

Answer 11

Adenosine (ribose + adenine) and three phosphate molecules (bonds between the molecules is where the energy is stored).

Question 12

What is the main difference between ADP and ATP?

Answer 12

Two phosphate molecules vs three, respectively.

Question 13

What is the idea of catabolism or hydrolysis with regards to ATP?

Answer 13

Breaking down ATP to ADP in order to release energy - ATPase is the enzyme which allows this to happen.

Question 14

What is the idea of anabolism or synthesis with regards to ATP?

Answer 14

Adding a phosphate group to ADP to form ATP which can be stored - ATP synthase is the enzyme which allows this to happen.

Question 15

What is the importance of ATP in energy transfer?

Answer 15

A tiny amount is needed in order for the breakdown of fuels to begin.

Question 16

Why does our body not store large amounts of ATP?

Answer 16

It is very molecularly heavy and we require a ton of it (~1kg of ATP is consumed hourly at rest, can increase 100 fold during exercise)

Question 17

What is an enzyme? What are three important things to note with regards to them?

Answer 17

A biological catalyst that increases the rate of a chemical reaction.
1. Does not cause a reaction to occur - simply speeds it up
2. Does not alter free energy change
3. Lower activation energy required for a chemical reaction to occur

Question 18

How do enzymes work mechanically?

Answer 18

Substrate binds to the active site of an enzyme formulating the E-S complex, product is formed and the enzyme separates from it to be used again

Question 19

What are the four factors which can influence enzyme activity?

Answer 19

1. Substrate and product concentrations - increased substrate will promote faster and greater enzyme activity whereas increased product concentrations will slow down and inhibit enzyme activity (negative feedback to the rate limiting enzyme)
2. Modulators - stimulators: speed up the rate of a reaction at a given substrate concentration, Inhibitors: decrease the rate of a reaction at a given substrate concentration
   i.e., key stimulator: ADP: an accumulation can signal to the enzyme ATP synthase to regenerate ATP, key inhibitor: ATP: an accumulation can signal ATP synthase to minimize or stop activity
3. Temperature
4. pH

Question 20

Are you able to increase the number of enzymes that you can use?

Answer 20

Yes, through exercise training. Detraining can decrease the number of enzymes.

Question 21

At what temperature do enzymes perform the best?

Answer 21

Approximately 38 degrees, colder or hotter (can denature an enzyme causing a very steep drop off) decreases the rate of the reaction

Question 22

At what pH do enzymes perform the best?

Answer 22

Approximately 7 (neutral)

Question 23

How can exercise alter our muscle pH? How do athletes buffer this affect?

Answer 23

Muscle pH becomes more acidic (decreases to 6.5) due to hydrogen ion accumulation from the lactic acid that is produced - can negatively impact performance. Athletes can ingest sodium bicarbonate before exercising which raises ones muscle pH in preparation for the drop

Question 24

What is one disadvantage that arises from the consumption of sodium bicarbonate (tums)?

Answer 24

Gastrointestinal distress (need to go to the bathroom)

Question 25

What are the three major fuel sources and their components?

Answer 25

Carbohydrates (glucose, liver and muscle glycogen (majority is muscle) - stored in SKM and liver), fats (FA’s - circulate in the blood, adipose and intramuscular TG’s (majority is adipose) - stored in SKM and adipose tissue), protein (AA’s and enzymes)

95-100% of total energy comes from CHO and fats.

Question 26

What are the three key tissues involved in exercise metabolism? Describe their functions:

Answer 26

1. SKM - site of where most metabolism occurs
2. Liver - can repurpose lactic acid received from SKM to glucose, can provide SKM glucose
3. Adipose tissue - components of broken down TG’s can be given to SKM to be used for energy, glycerol can go to the liver to be repurposed into glucose

Question 27

Explain the concept of supply and demand with regards to ATP:

Answer 27

At the initial onset of exercise, the reaction ATP + H2O -> ADP + Pi occurs. It is catalyzed by an enzyme known as ATPase (three types: myosin - breaks down ATP needed for crossbirdge cycling, Ca2+ - breaks down ATP needed for calcium to be pumped out of the SR pumps, Na/K+ - breaks down ATP for nerve impulses). These enzymes together produce a demand which is met by the three energy systems as a supply - Pcr, non oxidative glycolysis, aerobic.

Question 28

What is the difference between Type I and Type II fibers?

Answer 28

Type I: good for short intensity and long duration exercise, require oxygen for ATP production

Type II: good for high intensity, short duration exercise, generate ATP anaerobically

IIa - short, intense, endurance activities
IIx - short, explosive sprints

Question 29

How much energy do the three macronutrients contain?

Answer 29

CHO - 4.1, Fats - 9.4, Protein - 4.1