AP Unit 2 Cells: Cell Size and Plasma Membrane

cellular metabolism

chemical activities of cells, directly depends on cell size

high surface area to volume ratio

smaller cells: more efficient at exchanging material across the plasma membrane

low surface area to volume ratio

larger cells: less efficient at exchanging material across the membrane, but has more storage

surface area

The measurement of the outer surface of an object.

volume

The amount of space an object takes up

amphipathic

having both a hydrophilic region and a hydrophobic region

phospholipid head

polar (hydrophilic) contains a phosphate group and glycerol

phospholipid tail

non-polar (hydrophobic) contains fatty acid chains

phospholipid bilayer

A double layer of phospholipids that makes up plasma and organelle membranes.

Hydrophobic

Water fearing

Hydrophilic

Water loving

Fluidity of the cell membrane

maintained by the weak hydrophobic interactions between the tails of the phospholipids , allowing them to move/drift

increases fluidity of plasma membrane under cold conditions

cholesterol and more unsaturated fatty acids

integral proteins

embedded in the phospholipid bilayer, spanning the membrane

peripheral proteins

The proteins of a membrane that are not embedded in the lipid bilayer; they are bound to the surface of the membrane.

glycolipids

Membrane carbohydrates that are covalently bonded to lipids.

glycoproteins

Membrane carbohydrates that are covalently bonded to proteins.

mosaic

made of a variety of macromolecules (phospholipids, cholesterol, proteins, and carbohydrates)

Aquaporins

water channel proteins

channel proteins

have a hydrophilic channel that certain molecules or ions can use as a tunnel to get across the membrane

carrier proteins

a protein that transports substances across a cell membrane buy binding to the molecules and changing shape

cell wall

A rigid layer that surrounds the plasma membrane of plant cells and is composed of cellulose

Plasmodesmata

channels through cell walls that connect the cytoplasms of adjacent cells and allow for cell-to-cell communication