Anatomy and Physiology - Energy for exercise Flashcards
What are the three energy systems?
- ATP/PC Energy system
- Glycolytic Energy system
- Aerobic Energy system
ATP/PC System
- Very high intensity activity/exercise
- Lasts from 3-10 seconds
- Used predominantly in events such as the 100m sprint
Glycolytic energy system
- Used for high intensity exercise/activity
- Lasts up to 3 minutes
- Used in the last lap of 1500M with the ATP/PC system being used in the last 50m of the race
Aerobic energy
- Used for low to moderate intensity exercise/activity
- Lasts for +3 minutes
- Used in Events such as long distance cycling and long distance running especially
What are the three sections of the Aerobic energy system?
- Aerobic glycolysis
- Krebs cycle
- Electron transport chain (ETC)
Aerobic glycolysis
• Breakdown of carbohydrates (in the form of glucose or glycogen) into pyruvic acid and resulting in the production of two ATP molecules.
• A total of 10 chemical reactions are required to convert carbohydrates into pyruvic acid.
• This takes place In the sarcoplasm.
- 2 ATP MOLECULES PRODUCED
Kreb’s cycle
• The pyruvic acid produced during aerobic glycolysis enters the mitochondria and is immediately converted to Acetyl Conzyme A.
This combines with Oxaloacetic acid to form a 6 carbon compound known as citric acid.
- 2 ATP MOLECULES PRODUCED
Electron transport chain
• Hydrogen atoms from the Krebs cycle are carried through the electron transport chain along the cristae (the inner membranes of the mitochondria) by NAD and FAD and is then split into a protein (H+) and an electron (H-).
• The electrons are then subject to a series of redox reactions which release a large amount of energy in order to resynthesise ATP.
• The protons also create energy by moving back through the inner membrane of the Mitochondria because of the redox reactions.
- 34 ATP MOLECULES PRODUCED
ATP/PC Process
- High-energy compound broken down by ATPase.
- This provides an immediate source of energy for muscular contraction exothermically.
- ATP/PC can be resynthesised to maintain energy production using energy from food fuel breakdown.
- It resynthesises ATP from the breakdown of phosphorcreatine (PC) by créatine kinase in a coupled reaction
- PC -> C +P + energy in an anaerobic reaction in the sarcoplasm yielding one mile of ATP.
Glycolytic process
- It resynthesises ATP from the breakdown of glycogen by GPP and glucose by PFK.
Glucose —> pyruvic acid + energy in the sarcoplasm yielding 2 miles of ATP.
Pyruvic acid —> lactic acid by LDH due to anaerobic conditions which accumulates to reach OBLA, causing fatigue.
Aerobic process
It resynthesises ATP from the breakdown of glycogen, glucose and FFAs by GPP, PFK or lipase.
Yields 38 moles of ATP in total
Aerobic system - Glycolysis equation
Glucose —> Pyruvic acid + energy by PFK in the sarcoplasm.
Aerobic system - Krebs cycle equation
Acetyl CoA —> CO2 + H + Energy in the matrix if the mitochondria
Aerobic system - Electron transport chain equation
H —> H2O + energy in the cristae of the mitochondria.
Energy continuum
Relative contribution of each energy system to overall energy production depending on intensity and duration.
Buffering capacity
The ability of hydrogen carbonate ions (buffers) to neutralise the effects of lactic acid in the blood stream
PFK
An enzyme which catalyses the breakdown of glucose (glycolysis)
OBLA
Onset blood lactate accumulation.
The point at which fatigue sets in
ATPase
An enzyme which catalysés the breakdown of ATP
Exothermic reaction
A chemical reaction which releases energy
Endothermic reaction
A chemical reaction which absorbs energy
Coupled reaction
Where the products of one reaction are used in another reaction.
Créatine kinase
An enzyme which catalyses the breakdown of Phosphocreatine (pc)
Phosphocreatine
A high energy compound stored in the muscle cell and broken down for ATP resynthesis
