movement of substances

factors affecting rate of diffusion

concentration gradient, diffusion distance, surface area to volume ratio

relationship between surface area to volume ratio and rate of diffusion

larger surface area to volume ratio, higher rate of diffusion

glucose molecules or starch molecules bigger?

STARCH! (please get this right)

solution with higher water potential than cell is called?

HYPOTONIC solution

solution with same water potential as cell is called?

ISOTONIC solution

solution with lesser water potential than cell is called?

HYPERTONIC solution

what happens when animal and plant cell are put in hypertonic solution?

animal cell shrinks, and becomes crenated. plant cell vacuole shrinks and cell becomes flaccid, the cytoplasm shrinks away from cell wall and cell becomes plasmolysed.

difference between diffusion and osmosis + active transport?

diffusion can occur with or without a partially permeable membrane, but osmosis and active transport both require a partially permanent membrane

what molecules require facilitated diffusion?

hydrophilic molecules, such as glucose, and ions such as sodium, potassium and calcium. all of them are unable to freely diffuse through hydrophobic core of plasma membrane.

what are channel proteins?

a channel protein provides hydrophilic pore, through which only a particular ion or charged molecule can diffuse readily through the membrane.

what are aquaporins?

aquaporins are a type of channel proteins, and allow water molecules to pass through the phospholipid bilayer by zipping between phospholipid molecules and through the aquaporins.

what are carrier proteins?

a carrier protein facilities movement of a particular molecule through the membrane as the protein changes its shape. the hydrophilic interior of the carrier protein contains a binding site for its molecule, and when the molecule binds to its binding site, this triggers the protein shape to change, transporting the molecule across the membrane. once it exists the carrier protein, the protein will return to its regular shape. the carrier proteins

what molecules use channel proteins?

small ions, and water (via aquaporins)

what molecules use carrier proteins?

large polar molecules