Unit 1: Energy Production

Question 1

What is the role of ATP

Answer 1

ATP is an energy source used throughout the body. It provides the energy needed for cross bridge formation in muscle contraction.
Stored chemical energy

Question 2

What is an absolute and what is a relative workload. Give examples

Answer 2

Absolute: known or assumed to be below an individual’s maximum and is constant for everyone
i.e. all class members exercise at 150 bpm
May be light for some and high for others

Relative: individualizes a workload for each person
A heart rate workload may be to ask each person to work at a heart rate of 60% of heart rate max
This may be 96 bpm for an older individual and 120 bpm for a younger individual

Question 3

Name the 3 energy systems

Answer 3

1. ATP – CP system (alactic system) POWER
2. anaerobic glycolysis (lactic system) SPEED
3. aerobic metabolism (oxidative phosphorylation) ENDURANCE

Question 4

How many ATP does cellular respiration and glycolysis produce

Answer 4

38

Question 5

Describe Cellular respiration and Glycolysis

Answer 5

Can use CHO, FFA and PRO as substrate. Has Acetyl COA as the central converting substance. Glycolysis is first step when using CHO. Glycolysis needs no O2, and has glucose transported via GLUT transporters (GLUT 1 at rest GLUT 4 at exercise). Glycolysis is mediated by enzymes that include:
- hexokinase
- PFK
- Pyruvate Kinase
- 1,6 Diphosphate
- O2 (inhibits glycolysis).
Now NAD needs to be converted to Acetyl COA (central conversion substance) with use of O2. If no O2 NAD goes to H+ to accept H+
Net gain of 3 ATP w glycolysis

Question 6

Name the rate limiting enzymes in glycolysis

Answer 6

Hexokinase
PFK
Pyruvate Kinase
1,6 diphosphate
O2

Question 7

What happens to hydrogen during CR/glycolysis with activity

Answer 7

• with moderate activity, hydrogen is oxidized at the same rate as production à pyruvate (+ H2O) (slow glycolysis – glucose)
  • with intense activity, hydrogen production exceeds oxidation à lactate production from pyruvate (lactate dehydrogenase) (fast glycolysis – glycogen)
  • therefore lactate accumulation signals high anaerobic metabolism

Question 8

What does PFK do?

Answer 8

Breaks down glucose into pyruvate to produce ATP w no O2

Question 9

What is the primary outcome of the krebs cycle

Answer 9

generating electrons in the form of H+ to pass NAD and FAD into respiratory chain

Question 10

Role of NAD and FAD

Answer 10

Both transport hydrogen
reduce hydrogen when picking up and oxidize them

Question 11

Summarize the krebs cycle

Answer 11

Does not use O2 but must be aerobic, occurs in mitochondrial matrix and gets 2 ATP

Question 12

Explain ETC and Oxidative Phosphorlation

Answer 12

• A series of chemical reaction in the mitochondria that transfer electrons from the hydrogen atom carried NAD and FAD to oxygen
  
  • Water is formed as a by-product
  • The electrochemical energy released by the hydrogen ions is coupled to the formation of ATP from ADP and Pi via ATP synthase

Question 13

How many ATP for one glucose in skelatal muscle

Answer 13

• 2 ATP from anaerobic glycolysis
• 2 ATP from Acetyl-CoA in the Krebs Cycle
• 26 ATP from ETS/OP
  TOTAL 30 ATP (net)

Question 14

Where is CHO stored in body

Answer 14

Blood glucose 5-7g
Intramuscular glycogen 300-400 g
Liver Glycogen 100g

Question 15

Describe muscle vs liver glycogen

Answer 15

Muscle: Muscle cells lack enzyme glocise-6-phosphate, so intramuscular glycogen stores are destined for that muscle

Liver: Liver glycogen can be converted to glucose and used in blood for general use

Question 16

Where are triglycerides available

Answer 16

Intramuscular fat stores 3000 kcal
Adipose tissue stores virtually unlimited

Question 17

Describe fat mobilization/beta oxidation

Answer 17

The breakdown of TG into FFA is catalyzed by HSL. FFA that is transported in the blood is bound to albumin, then gets taken to acetyl COA. FFAs taken up by receptors on muscle cell then transported to mitochondrial matrix Whatever is converted into glycerol can enter the cytoplasm in some cells or be converted to glucose. beta oxidation is breaking down fat and enetring as Acetyl COA

Question 18

How many ATP from fat

Answer 18

147 from one 18 carbon fat molecule
for each triglyceride 441
total 460 atp

Question 19

Why cant we burn fats like CHO

Answer 19

need pyruvate to keep fat burn going - so, during exercise:
○ you can burn a combination of fat and CHO
○ you can burn only CHO (e.g. during high-intensity exercise)
○ but you can not burn only fat
○ therefore, carbohydrate sparing during exercise is important

Question 20

What is hitting the wall and how does it happen

Answer 20

Its when you have glycogen depletion and occurs because of:
- prolonged exercise duration (e.g. marathon, triathlon, etc.)
- multiple repetitive bouts of extremely high intensity work
- consecutive days of training (especially with inadequate CHO diet)
- inadequate energy intake/dietary limit of carbohydrates

Question 21

What is carb loading

Answer 21

When you load up on carbs before exercise
- CHO loading results in additional storage of glycogen in the muscle fibers that can be 2-3 times of normal
- This avoids hitting the wall

Question 22

What can low CHO do to Energy metabolism

Answer 22

• If CHO is inadequate, oxaloacetate is converted to glucose to maintain brain and nervous system function
• oxaloacetate is necessary to Krebs
• Without oxaloacetate acetyl coA derived from fatty acids become metabolites called ketones
• Ketones can be used as fuel or if accumulate can disrupt acid-base balance
• During exercise aerobically trained individuals can use ketones more effectively than untrained individuals
  cycle

Question 23

What is keto and effect on exercise

Answer 23

Is a significant reduction in CHO intake. Promotes the use of ketones as fuel. low muscle glycogen availability promotes molecular changes that enhance training-derived endurance adaptations. body can reserve large amounts of energy in the form of fat

Question 24

Describe protein metabolism

Answer 24

To be used a fuel must remove nitrogen
- Mostly undergo transamination – transfer of amino group from an amino acid to a keto acid
* Amino acid can enter into energy metabolism
- Keto acid forms alanine which undergoes gluconeogenesis containing amino group

Question 25

Describe intramuscular cellular regulation

Answer 25

• When ATP is adequate there is no need to increase production – negative feedback.
• When muscle activity begins and ATP is broken down into ADP and P these by products stimulate production of ATP so muscle contraction can continue

Question 26

Describe Extracelluar regulation of metabolism

Answer 26

• Regulation of blood glucose levels governed jointly by ANS and endocrine system
• When exercise begins, working muscles signal neurohormonal response from hypothalamus
• Hypothalamus stimulates anterior pituitary and SNS
• Norepinephrine and epinephrine are released and act directly on fuel sites
  ○ Increase in mobilization and utilization of FFA
  ○ Increase in breakdown of glycogen and increase in gluconeogenesis
  ○ Decrease in uptake of glucose into non working cells