5.4 Active Transport
First review @October 16, 2023
Practise Q's Done
during active transport, particles must be moved up a concentration gradient at a rate
faster than the process of diffusion, which requires energy from an external source— this
is active transport
Active transport
movement of molecules or ions into or out of a cell from an area of low concentration to
an area of high concentration up a concentration gradient
requires energy and carrier proteins
energy is required since particles are being moved up a concentration gradient in the
opposite direction to diffusion which is a passive process
the metabolic energy supplied is from ATP
carrier proteins are intrinsic proteins and act as ‘pumps’ for the molecules and ions
process of active transport
1. the molecule or ion being transported binds to the receptors in the channel of the
carrier proteins on the outside of the cell
2. on the inside of the cell, ATP binds to the carrier protein and is hydrolysed to form
ADP and a phosphate
3. this binding of the phosphate to the carrier protein causes the carrier protein to
change shape and open up on the inside of the cell
4. the molecule or ion is released into the cell
5. the phosphate molecule is released form the carrier protein and recombines with
ADP to reform ATP
6. the carrier protein returns to its original shape
the process of active transport is selective, not any molecule or ion can just pass
through the carrier proteins-
5.4 Active Transport 1
First review @October 16, 2023
Practise Q's Done
during active transport, particles must be moved up a concentration gradient at a rate
faster than the process of diffusion, which requires energy from an external source— this
is active transport
Active transport
movement of molecules or ions into or out of a cell from an area of low concentration to
an area of high concentration up a concentration gradient
requires energy and carrier proteins
energy is required since particles are being moved up a concentration gradient in the
opposite direction to diffusion which is a passive process
the metabolic energy supplied is from ATP
carrier proteins are intrinsic proteins and act as ‘pumps’ for the molecules and ions
process of active transport
1. the molecule or ion being transported binds to the receptors in the channel of the
carrier proteins on the outside of the cell
2. on the inside of the cell, ATP binds to the carrier protein and is hydrolysed to form
ADP and a phosphate
3. this binding of the phosphate to the carrier protein causes the carrier protein to
change shape and open up on the inside of the cell
4. the molecule or ion is released into the cell
5. the phosphate molecule is released form the carrier protein and recombines with
ADP to reform ATP
6. the carrier protein returns to its original shape
the process of active transport is selective, not any molecule or ion can just pass
through the carrier proteins-
5.4 Active Transport 1
