Question

Compare and contrast active and passive transport. Discuss the different forms and how they function. Be descriptive on each and every similarity and difference.  

Answer 1

Compare and contrast active and passive transport.

Similarities:

• In both active and passive transport there is involvement of movement of ions.
• In active transport as well as passive transport ion channels would be used. In active transport, ions would be used to travel using energy, against the gradient, via the ion channels, whereas in passive transport ion channels will be used to move ions with the chemical gradient.
• Both the processes help maintain cell homeostasis.

Difference:

• In active transport energy is used whereas in passive transport energy is not used.
• Active transport is against the chemical gradient whereas passive transport is with the chemical gradient.
• In active transport larger and complex molecules like proteins or sugars are transported whereas in passive transport smaller molecules like water, lipids, oxygen etc.

Discuss the different forms and how they function.

The different forms of passive transport are:

- facilitated diffusion: a passive spontaneous transport process of molecules via transmembrane proteins.

- diffusion: net movement of atoms or molecules where movement would occur from a region of high concentration to a region of low concentration that has a low chemical potential.

- osmosis: spontaneous movement of solvent molecules that occur via a semi permeable membrane from a region of low solute concentration to high solute concentration such that solute concentration on both sides of the membrane would be equal.

Different forms of active transport are:

- Symporter: symporters would use downhill movement of a single solute species that would occur from a high concentration to low concentration and another molecule would move from a low to high concentration, in the same direction.

- antiporter: in this mode of transport, two ion species or solutes are moved in and out of the cells simultaneously, in opposite directions, where one would move along the gradient that would yield entropic energy, which would drive the movement of the other molecule against the gradient,