Module 2
Exchange and Transport
Unit One
Cells, Exchange and Transport
AS Biology
OCR Specification
, Exchange
• In groups
– discuss what is meant by the word
“exchange”
– Apply the word exchange to a biological
concept
– Exchange takes place over surfaces
• Write down features of a good exchange
surface
• Which processes are used in the exchange
of substances
, Learning Outcomes
• Explain, in terms of surface
area:volume ratio, why multicellular
organisms need specialised
exchange surfaces and single-celled
organisms do not.
, Exchanges between
organisms and their
environment
• Exchange can take place in two ways
– Passively (no energy is required)
• E.g. diffusion and osmosis
– Actively (energy is required)
• Active transport
• Pinocytosis and phagocytosis
Exchange and Transport
Unit One
Cells, Exchange and Transport
AS Biology
OCR Specification
, Exchange
• In groups
– discuss what is meant by the word
“exchange”
– Apply the word exchange to a biological
concept
– Exchange takes place over surfaces
• Write down features of a good exchange
surface
• Which processes are used in the exchange
of substances
, Learning Outcomes
• Explain, in terms of surface
area:volume ratio, why multicellular
organisms need specialised
exchange surfaces and single-celled
organisms do not.
, Exchanges between
organisms and their
environment
• Exchange can take place in two ways
– Passively (no energy is required)
• E.g. diffusion and osmosis
– Actively (energy is required)
• Active transport
• Pinocytosis and phagocytosis
