Communication and
Homeostasis
, Learning Objective
a) The need for communication
systems in multicellular organism
To include the need for animals and plants to
respond to changes in the internal and extern
environment and to coordinate the activities o
different organs
,The need for control.
All cellular reactions are controlled by enzymes, so organisms need t
maintain constant conditions to ensure optimum reaction rates.
What conditions affect the rate of an enzyme controlled reaction?
temperature
pH
substrate concentration
enzyme concentration
, The need for control.
Any changes in the external or internal environment will place stress on an o
so an organism has to respond to changes in the environment.
By responding to a stimulus in the environment an organism increases its chan
survival (also helps to give optimal conditions for metabolism). Multicellular
organisms require communication systems to coordinate their responses as th
are specialised and need to work together in order for a multicellular organis
perform a function.
Stimulus – an environmental change
Response – the way in which an organism changes its behaviour or phys
Think about how the environment changes (in the long term and the sh
term) and note down your ideas in your notes. – include changes to bot
internal and external environment.