Energy for Exercise Flashcards
What is energy?
the capacity to perform work and can exist in chemical, potential and kinetic forms
Explain chemical energy?
it is in the food we eat and can be stored as potential energy in the body tissues and converted into kinetic energy as we contract out muscles
What can the food we eat be stored as ?
- amino acids
- triglyceriides
- glycogen
What happens when the fuels are metabolised?
they are converted into the compound (adenosine triphosphate)
What is the metabolism?
- chemical processes that occur within a cell to maintain life. Some substances are broken down
WHat happens when ATP is broken down?
energy is provided for cellular processes such as digestion, nerve transmission and muscular contraction
Where is ATP stored?
in muscle cells
What is the only immediate source of energy for muscular contraction?
ATP
What is ATP made up of?
one adenosine and three phosphates
How is the energy extracted from ATP?
the enzyme ATPase is released which stimulates the final high energy bond to be broken. exothermic reaction releases energy for muscular contraction and leaved adenosine diphosphate and a single phosphate
Give the breakdown of ATP reaction?
ATP –> ADP + P + Enrergy
How long is the store of ATP in the muscle cell?
2-3 seconds
Give the equation for the resynthesis of ATP?
ADP + P + Energy –> ATP
What are the three energy systems that breakdown food fuels to provide energy for ATP resythesis?
- ATP-PC system
- glycolytic system
- aerobic system
What happens if ATP fails to be resynthesised
no energy released for muscular contraction and fatigue will quickly set in
WHen does the ATP-PC system kick in?
during very high-intensity activity after the first two seconds of intense activity depletes the original ATP stores
Explain how the ATP-PC system kicks in?
ATP levels fall dramatically and ADP and P levels rise, trigers release of creatine kinase
What is creatine kinase>
an enzyme which catalyses the breakdown of phosphocreatine
What is creatine phosphate made up of?
creatine with a high energy phosphate bond
How and where is the PC broken down?
broken down anaerobically in the sarcoplasm
What is a coupled reaction?
where the products of one reaction are used in another
What are the strengths of the ATP-PC system?
- no delay of oxygen
- PC readily available in the muscle cell
- simple and rapid
Weaknesses of ATP-PC system?
- low ATP yield and small PC sotres lead to rapid fatigue
When does the glycolytic system kick in?
during high intensity activity after the first ten seconds of intense activity exhausts PC stores and ATP levels fall
Explain how the ATP system kicks in?
- ATP and P levels rise again and trigger release of phosphofructokinase
What is phosphofructokinase ?
an enzyme which catalyses the breakdown of glucose
what happens if glucose levels fall in glycolytic system?
- glycogen phosphorylase is released, converting glycogen into glucose to maintain its concentration in the blood stream
What is glycogen phosphorylase (GPP)?
an enzyme which catalyses the breakdown of stored glycogen
What is the process of the breakdown of glucose in the absence of oxygen ?
anaerobic glycolysis
What does anaerobic glycolysis produce?
pyruvic acid
For every mole of glucose broken down, how many moles of ATP are made?
two
How long does glycolytic ATP resynthesis take place for?
three minutes
What happens when at high intensity excersise and energy extraction from pyruvic acid cant continue?
- lactate dehydrogenase (LDH) is released
What is LDH?
an enzyme which catalyses the conversion of pyruvic acid into lactic acid, which accumulates and slows ATP resynthesis
Explain how muscle fatigue occurs in the glycolytic system?
anaerobic glycolysis frees only about 5% of potential energy, lactic acid levels rise, PH in muscle cells decreases, inhibits enzymes, prevents further breakdown of fuel and ATP resynthesis
What is the point where blood lactate levels significantly rise?
OBLA
breakdown of glucose equation? glycolytic system
glucose –> pyruvic acid + energy
lactic acid production equation? glycolytic system
Pyruvic acid –> lactic acid
Resythnthesis of ATP equation? glycolytic system
energy + 2P + 2ADP —> 2ATP
Breakdown of ATP equation? glycolytic system
ATP —> ADP + P + energy from muscular contraction
When does the aerobic system kick in?
during low-moderate intensity activity
What three stages are in the aerobic system?
- aerobic glycolysis
- kerbs cycle
- electron transport chain
What does aerobic glycolysis in the sarcoplasn do?
converts glucose into pyruvic acid with the enzyme PFK catalysing the reaction
What does aerobic glycolysis mean?
- releases enough energy to resynthesise two moles of ATP
What does converting glycogen into glucose result in from aerobic glycolysis ?
maintains process for extended periods of time, oxygen is now in sufficient supply, pyruvic acid is no longer converted into lactic acid. Link reaction occurs catalysed by coenzyme A (produces acetyl CoA), allows access to mitochondria
Explain Krebs cycle?
- acetyl CoA combines with oxaloacetic acid to form citric acid, oxidised through reactions. CO2, hydrogen and enough energy to resynthesise two moles of ATP released. Occurs in matrix of mitochondria
Type of reaction for ATP-PC system?
anaerobic
Site of reaction for ATP-PC ?
sarcoplasm
