CIE IGCSE Biology Unit 12: Respiration

uses of energy in the body of humans

-muscle contraction

-protein synthesis,

-cell division

-active transport

-growth,

-the passage of nerve impulses

-maintenance of a constant body temperature

aerobic respiration

the chemical reactions in cells that use oxygen to break down nutrient molecules to release energy

Investigate the uptake of oxygen by respiring

organisms in arthropods

-Used for growth

-cell division

-active transport

Investigate the uptake of oxygen by respiring

organisms in germinating seeds

Needed for aerobic respiration to provide energy for embryo

the effect of temperature on the rate of respiration of germinating seeds

Suitable temperature is required for enzymes to function in seed to produce energy for germination

anaerobic respiration

the chemical reactions in cells that break down nutrient molecules to release energy without using oxygen. Releases much less energy per glucose molecule than aerobic respiration. Product formed is lactic acid which is later broken down into carbon dioxide and water when there is presence of oxygen

lactic acid

An organic acid that builds up in muscles and blood during vigorous exercise causing an oxygen debt

how the oxygen debt is removed during recovery

- aerobic respiration of lactic acid in the liver

- continuation, after exercise, of fast heart

rate to transport lactic acid in blood from

muscles to the liver

- continuation, after exercise, of deeper

breathing supplying oxygen for aerobic

respiration of lactic acid