1 Compare and contrast the topdown and bottom up approaches

1. Compare and contrast the top-down and bottom up approaches to the study of physiology.

2. Discuss the functional differences between ionotropic and metabotropic receptors.

3. What are the relative advantages and disadvantages of large and small body size in frigid places?

Solution

1. Top down approach (from Higher level to lower level): Starts from an Organism and ends in molecules

Organism- organ - tissues -cells - molecules

Bottum up approach (from lower level to higher level) : Starts from molecules and ends in an organism

molecules - cells - tissues - organ - organism

2. Ionotropic receptor have channels that will open by changing its shape when a ligand binds to it. So it acts quickly to give immediate response by allowing ions inside. But the ligand may not be in place for a long time so the effect is short term.

Metabotropic receptors do not have any channels to open or close. Instead when it is activated by a ligand, it binds to G protein which in turn activates second messengers to end up in the final product. So it takes very long time to activate one after the other but results in a much wider range of responses.