excercise physiology exam 1 chapters 1-4

Question 1

A.V. Hill – nobel prize

Answer 1

Heat production during muscle contraction and recovery

Question 2

Otto Meyerhof –nobel prize

Answer 2

Relationship of O2 consumption and lactic acid in muscle

Question 3

–August Krogh-nobel prize

Answer 3

Function of the capillary circulation

Question 4

D.B. Dill

Answer 4

–Directed the Harvard fatigue lab from 1927–1947; D.B Dill Conducted research in numerous areas such as Exercise, clinical, and environmental physiology. Basis of much of what we know today. He was able to make precise measurements with” new” instruments and techniques. Active Research Areas in the Harvard Fatigue Laboratory
–Aging –Blood–Physical fitness –Metabolism–Environmental physiology –Clinical physiology

Question 5

Homeostasis

Answer 5

Maintenance of a constant and “normal” internal environment

Question 6

Steady state

Answer 6

–Physiological variable is unchanging, but not necessarily “normal it is the Balance between demands placed on body and the body’s response to those demands

Question 7

Oxidation

Answer 7

Removing an electron

Question 8

Reduction

Answer 8

Addition of an electron

Question 9

Endergonic reactions

Answer 9

Require energy to be added to the reactant

Question 10

Enzymes

Answer 10

Catalysts that regulate the speed of reactions

Lower the energy of activation but do not alter nature of reaction

Question 11

Factors that regulate enzyme activity

Answer 11

Temperature, ph

Question 12

Exergonic reactions

Answer 12

Release energy

Question 13

Coupled reactions

Answer 13

Release of energy in an exergonic reaction drives an endergonic reaction

Question 14

Metabolism

Answer 14

Sum of all chemical reactions that occur in the body Anabolic reactions Synthesis of molecules Catabolic reactions
Breakdown of molecules

Question 15

Bioenergetics

Answer 15

Converting foodstuffs (fats, proteins, carbohydrates) into energy

Question 16

Cell membrane

Answer 16

Semipermeable membrane that separates the cell from the extracellular environment

Question 17

Nucleus

Answer 17

Contains genes that regulate protein synthesis

Molecular biology

Question 18

Cytoplasm

Answer 18

(called sarcoplasm in muscle). Fluid portion of cell
Contains organelles
Mitochondria

Question 19

Negative Feedback

Answer 19

Response reverses the initial disturbance in homeostasis

Question 20

example of negative feedback

Answer 20

Increase in extracellular CO2 triggers a receptor which Sends information to respiratory control center. Respiratory muscles are activated to increase breathing now CO2 concentration returns to normal

Question 21

Coenzyme functions

Answer 21

(1) Substrate such as pyruvate, need enzymes to be converted to other substrate.
(2) Before enzyme attaches to vitamin coenzyme, enzyme is in a closed position. After attachment, it is in opening position.

(3) The open, activated enzyme accepts the substrate.
(4) Split the substrate into two compounds while releasing the enzyme and vitamin coenzyme.

Question 22

Some factors that affect enzyme function are

Answer 22

Temperature–Small rise in body temperature increases enzyme activity–Exercise results in increased body temperature-pH–Changes in pH reduces enzyme activity–Lactic acid produced during exercise

Question 23

Carbohydrates

Answer 23

Blood sugar Glycogen Storage form of glucose in liver and muscle
Synthesized by enzyme glycogen synthase Glycogenolysis Breakdown of glycogen to glucose

Question 24

Fats:

Answer 24

Fatty acids
Triglycerides → glycerol and fatty acids
Storage form of fat in muscle and adipose tissue. Breaks down into glycerol and fatty acids Phospholipids
Not used as an energy source
Provide the structural integrity of cell membrane Provide the insulation of sheath around nerve fibers

Question 25

Steroids

Answer 25

The most common steroid is cholesterol

–Needed to synthesize sex hormones

Question 26

Steroid hormones-

Answer 26

are lipid soluble, most are formed from cholesterol.

Question 27

Non-steroid hormones -

Answer 27

are formed from proteins and amino acid.

Question 28

Protein

Answer 28

Composed of amino acids nine amino acids are essential and cannot be made by our body. Some can be converted to glucose in the liver also known as Gluconeogenesis. Others can be converted to metabolic intermediates (e.g some enzymes)
Contribute as a fuel in muscle in the bioenergetics pathways.

Question 29

Steps in protein synthesis

Answer 29

1. DNA contains information to produce proteins.
2. Transcription produces mRNA.
3. mRNA leaves nucleus and binds to ribosome.
4. Amino acids are carried to the ribosome by tRNA.
5. In translation, mRNA is used to determine the arrangement of amino acids in the polypeptide chain(protein synthesis).

Question 30

Does Creatine Supplementation Improve Exercise Performance?

Answer 30

Depletion of PC may limit short-term, high-intensity exercise
Creatine monohydrate supplementation
Increased muscle PC stores
Some studies show improved performance in short-term, high-intensity exercise
Inconsistent results may be due to water retention and weight gain
Increased strength and fat-free mass with resistance training
Creatine supplementation for 8 weeks does not appear to pose health risks

Question 31

Fast glycolysis

Answer 31

energy derived from the breakdown of glucose (or glycogen) to 2 (or 3) molecules of ATP and 2 molecules of lactic acid

Question 32

Lactic Acid – Implications for Performance

Answer 32

Lactic acid alters the pH of the cell

The higher acidity of the cell as a result of lactic acid production alters enzymatic activity (reactions occur at a slower rate)

The more lactic acid an athlete can produce, the greater power output the athlete can generate

A speed athlete must produce and tolerate great amounts of lactic acid to be successful

Lactic acid does not cause muscle soreness

Question 33

Lactic Acid or Lactate?

Answer 33

Terms lactic acid and lactate used interchangeably
Lactate is the conjugate base of lactic acid
Lactic acid is produced in glycolysis
Rapidly disassociates to lactate and H+

The ionization of lactic acid forms the conjugate base called lactate

Question 34

Non-oxidative System (Fast glycolysis)

Answer 34

Non-oxidative energy sources in muscle are the breakdown of glucose (simple sugar) and glycogen (stored in liver).

The breakdown of glucose: Glycolysis
The breakdown of glycogen: Glycogenolysis
3. In skeletal muscle, the concentration of free glucose is very low so the
most of potential energy available from non-oxidative energy sources
comes from the breakdown of glycogen .

4. Non-Oxidative system offers about 15 Kcal/mole energy for total
   muscle mass that is greater than immediate energy system
   (11.1 Kcal/mole)

Question 35

Aerobic Metabolism

Answer 35

Aerobic ATP production occurs inside the mitochondria and involves the interaction of 2 cooperating metabolic pathways.

Question 36

Aerobic Metabolism: krebs cycle

Answer 36

Primary function is to complete the oxidation (H+ removal) of CHO, Fats or proteins using NAD & FAD as hydrogen (energy) carriers.
H+ molecules (their electrons) contain the potential energy in food molecules.This energy (H+ molecule) can be used in ETC (Electron Transport Chain) to combine:
ADP + Pi ATP.

Question 37

Aerobic Metabolism: Electron TRansport chain

Answer 37

Electron transport chain results in pumping of H+ ions across inner mitochondrial membrane (from inner compartment to outer compartment)
Results in H+ gradient across membrane
Energy released to form ATP as H+ diffuse back across the inner membrane (from outer compartment to inner compartment)

Question 38

Aerobic ATP Production

Answer 38

Electron transport chain
Oxidative phosphorylation occurs in the mitochondria
Electrons removed from NADH and FADH are passed along a series of carriers (cytochromes) to produce ATP
Each NADH produces 2.5 ATP
Each FADH produces 1.5 ATP
H+ from NADH and FADH are accepted by O2 to form water

Question 39

Efficiency of Oxidative Phosphorylation

Answer 39

Aerobic metabolism of one molecule of glucose
Yields 32 ATP
Aerobic metabolism of one molecule of glycogen
Yields 33 ATP
Overall efficiency of aerobic respiration is 34%
66% of energy released as heat

Question 40

Amino Acid Metabolism

Answer 40

Protein primarily utilized to build and repair tissue

Contributes only small percentage of total energy production

2-3% of total energy at rest
12-15% of total energy at maximal, exhaustive exercise

Question 41

Rate-limiting enzymes

Answer 41

An enzyme that regulates the rate of a metabolic pathway

Question 42

Modulators of rate-limiting enzymes

Answer 42

Levels of ATP and ADP+Pi
High levels of ATP inhibit ATP production
Low levels of ATP and high levels of ADP+Pi stimulate ATP production
Calcium may stimulate aerobic ATP production

Question 43

Interaction Between Aerobic/Anaerobic ATP Production

Answer 43

Energy to perform exercise comes from an interaction between aerobic and anaerobic pathways
Effect of duration and intensity
Short-term, high-intensity activities
Greater contribution of anaerobic energy systems
Long-term, low to moderate-intensity exercise
Majority of ATP produced from aerobic sources

Question 44

VO2

Answer 44

Ability to Deliver & Use Oxygen

Question 45

Absolute VO2

Answer 45

Liters per minute (L/min)

Question 46

Relative VO2

Answer 46

ml per kg of body weight per minute (ml/kg/min)

Question 47

Energy Requirements at Rest

Answer 47

Almost 100% of ATP produced by aerobic metabolism

Blood lactate levels are low (<1.0 mmol/L)

Resting O2 consumption (70 kg adult):

0. 25 L/min (absolute VO2)
1. 5 ml/kg/min (relative VO2)

Question 48

MET

Answer 48

The expression of energy cost for activities in a simple unit.

Question 49

Oxygen Deficit:

Answer 49

the difference between the total oxygen actually consumed during exercise and the total oxygen required (consumed) in steady-rate from the start of exercise.

Question 50

Summary for O2 Deficit

Answer 50

As begin exercise, not producing enough O2 to do work:

(1) Accumulate Lactate			
(2) This is the O2 deficit			
(3) This will have to be paid back (metabolized later

Question 51

Excess Postexercise Oxygen Consumption (EPOC)

Answer 51

After exercise, O2 consumption does not return to resting levels immediately.

Then, the extra O2 consumed during recovery, above a resting baseline is called Excess Postexercise Oxygen Consumption (EPOC). EPOC is also termed O2 debt. Oxygen consumption remains elevated following exercise Classical term – oxygen debt Depends on intensity and duration of activity Rapid curve component (“Rapid” portion ) – steep decline
Slow curve component (“Slow” portion)

Question 52

Metabolic Responses to Prolonged Exercise

Answer 52

Prolonged exercise (>10 minutes)
ATP production primarily from aerobic metabolism
Steady-state oxygen uptake can generally be maintained during submaximal exercise
Prolonged exercise in a hot/humid environment or at high intensity
Upward drift in oxygen uptake over time
Due to body temperature and rising epinephrine and norepinephrine

Question 53

Lactate Threshold

Answer 53

The point at which blood lactic acid rises systematically during incremental exercise
Appears at ~50–60% VO2 max in untrained subjects
At higher work rates (65–80% VO2 max) in trained subjects

Question 54

Factors affecting lactate appearance and disappearance

Answer 54

[La] = rate of appearance – rate of disappearance
What affects appearance?
Production and release
Recruitment of fast twitch fibers
LDH isoform
Increased epinephrine
What affects disappearance?
Rate of uptake into non-working muscles
Oxidation by muscles, liver
Blood flow

Question 55

Removal of Lactate

Answer 55

70% - oxidized by other tissues

20% - converted to glycogen or glucose in liver (Cori Cycle)

10% - converted to amino acids

Question 56

RER (respiratory exchange ratio)

Answer 56

RER-respiratory exchange ratio