Transcript energy systems - The Grange School Blogs

ENERGY SYSTEMS
A2 Physical Education
‘The Energy Currency’
• Sometimes known as a
nucleotide.
• Chemical compound containing
base (adenine) a sugar (ribose)
and phosphate groups (bonded to
the sugar).
Storing energy
Energy ‘trickling’ into
your body from the
digestion of food
Re supply of energy
ATP
PCr
Blood
Glucose
2s
Muscle
and Liver
Glycogen
2–10 s
Fat
(lipids)
Protein
503 g (2012
kcal)
12 304 g (110 700
kcal)
?
ATP – Role
• Adenosine triphosphate (ATP) is the ‘energy currency’ of
the body – it transfers energy from one molecule to
another.
• All energy transfer within the body uses ATP (e.g. storage
of glycogen and mechanical work for exercise).
• Without ATP work cannot be carried out – it must be
constantly replenished.
• Each cell of the body has about a billion molecules of ATP
which are used, re-formed and reused… and so on…
• Energy transfer via ATP is controlled by the enzyme
ATPase.
ATP
• Consists of an adenine
molecule, a ribose
molecule and three
phosphate groups bonded
together.
• Energy for forming ATP
comes from the
catabolism of glucose
(known as cellular
respiration).
• ADP + P + Energy = ATP
ATP Splitting – adenosine diphosphate
• ATP + ATPase = ADP and energy
• ADP + P = ATP
• The extra P comes from the Creatine Phosphate (CP)
energy system.
• Hydrolysis (splitting) of ATP liberates 7.3 kcal of
energy.
Draw on board
Coupled reactions
• Coupled reactions occur in pairs.
• The breakdown of one compound provides energy for
building another compound.
• For example, if glucose is broken down the energy is
stored as ATP.
Redox reactions – at the smallest level
• Transfer of energy occurs via oxidation and reduction
reactions (or redox reactions).
• Oxidation is the removal of electrons from a molecule
decreasing potential energy.
• Reduction is the opposite: accepting an electron from
elsewhere resulting in an increase in potential energy.
• This usually occurs when dehydrogenase enzymes
accept electrons from hydrogen:
– NAD (Nicotinamide Adenine Dinucleotide)
– FAD (Flavin Adenine Dinucleotide)
Exothermic and endothermic reactions
• Exothermic (also known as exergonic)
– Produce more energy than they consume (give off energy)
– E.g. break down of complex molecules to smaller ones
– Such as: glycolysis, Krebs and electron transport
• Endothermic (also known as endergonic)
– Consume more energy than they produce
– E.g. combining simple molecules to form more complex
ones
– Formation of amino acids (peptide bonds) in muscle
hypertrophy
The Energy Systems
• ATP-PCr (immediate)
• Lactic acid (short-term)
• Aerobic (long-term)
GROUPS:
- What do you know about each of these energy systems?
- What ‘fuels’ are being used?
- Consider duration and intensity of exercise?
The Energy Systems
The Energy Systems
The Energy Systems
The Energy Systems
1.
2.
Immediate energy (ATP-PCr system): approx. 6–10 s
Short-term energy (Lactic Acid system): approx. 2 min
3.
Long-term energy (Aerobic system): more than 2 min
Press me
The Energy Systems
Immediate:
ATP-PCr
Short-term:
Lactic acid
(glycolysis)
Long-term:
Aerobic
Exam Question
1. With the use of an example for each, explain
the terms exothermic, endothermic and coupled
reactions.
(6 marks)