Ø is the transport
of substances across the cell membrane
(49) against a concentration
gradient.
Ø It involves (50) carrier proteins. Only substances that fit the (51) shape of the carrier proteins can be transported by
active transport
Ø
is an (52) active process and requires energy. Therefore it only
occurs in
(53) living cells which can
release energy by (54) respiration (呼吸作用).
Ø
Active transport is important for obtaining useful
substances, e.g. the absorption of:
n nutrients like (55)
glucose / amino acids / lipids in human small intestines
n (56) minerals from the soil
into the roots of plants.
http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter38/animation_-_mineral_uptake.html (動畫: 主動吸收礦物質)
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