BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS CELL MEMBRANE

SURFACE AREA: VOLUME & CELLS

--> Cells need to IMPORT nutrients and EXPORT wastes via diffusion (quickly and efficiently: best for cell= needs constant diffusion)

--> Small Cells have a HIGH surface area to volume ratio opposite for large

                        

                             SO WHY ARE CELLS SO SMALL?

• It is better to have many small cells that take up the same space as one large cell (back to being more efficient and quick in import/export)
• Surface Area is the cell membrane [import/export of wastes and nutrients]; SA to Volume ratio is smaller with one large cell so... it is unable to diffuse materials into and out of cell effectively or sometimes at all (that is why we are composed of billions of small cells)

To increase cell surface area (make a more effective cell):

• Divide (as mentioned, smaller cells that have a larger surface area to volume ratio are better!!!)
• Wavier Surfaces (Elongates/makes bigger while occupying same volume, bigger SA=better!!)
• Long and Skinny (Greater SA=better!!!, elongating to make more effective while occupying same volume as a fat cell)