Page 18 - 02 Cells Biology Notes

#19 Active transport

Sometimes substances are required to
be move against the Concentration
Gradient, or faster than they would by
Passive Transport. In these
cases, Active Processes are used,
which require energy.

There are many occasions when cells need to take in substances which are
only present in small quantities around them.

E.g. root hair cells in plants take in nitrate ions from the soil. Their
concentration are often higher inside the root hair cell than in the soil, so
the diffusion gradient is from the root hair à the soil. Despite this, the root
hair cells still can take nitrate ions in, by active transport.