Download KA 8 Summary Sheet

Biology: Key Area 8
Summary Sheet








Respiration is used to release energy for use in cells.
When food is burned, the chemical energy is given off as heat
energy.
To measure the energy in food, burn the food and measure the
temperature change in a boiling tube of water.
Energy in food can be measured in kilojoules (kJ).
Respiration is the chemical release of energy from the food we eat.
Glucose is the food molecule that is the main source of energy in
cells.
Respiration is controlled by enzymes.
The energy released from the breakdown of glucose is used to
generate Adenosine triphosphate (ATP).
Adenosine
Pi
Pi
Pi
ATP(HIGH
ENERGY
STATE)
Breakdown,
releasing
energy
Building up
(phosphorylation)
requiring energy
ADP+Pi(LOW
ENERGY
STATE)
Adenosine








Pi
Pi
energy
Pi
ATP is used for cellular activities including muscle cell contraction,
cell division, active transport, transmission of nerve impulses and
synthesis of protein.
Aerobic respiration is the complete breakdown of glucose into
Carbon Dioxide and water in the presence of oxygen.
Stage one of aerobic respiration is called glycolysis and does not
require oxygen – 2ATP are produced.
Stage two of aerobic respiration does require oxygen and produces
36ATP - 38ATP produced in total during aerobic respiration.
When no oxygen is present, glucose cannot be completely broken
down so the “fermentation pathway” is followed.
Stage one of the fermentation pathway is called glycolysis and
does not require oxygen - 2ATP are produced.
Stage two, in plants, produces carbon dioxide and ethanol and is an
irreversible reaction.
Stage two, in animals produces lactic acid and is a reversible
reaction.
Aerobic Respiration
Fermentation Pathway in Animals
Fermentation Pathway in Plants & Yeast