BIOL 2021- Final Exam Guide - Comprehensive Notes for the exam ( 37 pages long!)

• School: York University
• Department: Biology
• Course: BIOL 2021
• Professor: Patricia Lakin- Thomas

Document Summary

Example of light driven active transport: fig 10-31a bacteriorhodopsin: each bacteriorhodopsin molecule is folded into 7 closely packed transmembrane. Helices and contains a single light-absorbing group, or chromophore (in this case, retinal, same as in rhodopsin in photoreceptors of the vertebrate eye), which gives the protein its purple color. Atp-driven pumps: primary active transport = atp used directly. Coupled transporters: secondary active transport = uses ion gradients created by atp- driven pumps. In the plasma membrane of animal cells, na+ is the usual co-transported ion because its electrochemical gradient provides a large driving force for the active transport of a second molecule. The na+ that enters the cell during coupled transport is subsequently pumped out by an atp-driven na+-k+ pump in the plasma membrane, which, by maintaining the na+ gradient, indirectly drives the coupled transport. Such ion-driven coupled transporters as just described are said to mediate secondary active transport.