ib bio unit 1.2 quiz - membranes, transport, water potential

lipid bilayer

gives cell membranes a flexible structure that forms a strong barrier between the cell and its surroundings

Phosholipids

hydrophilic phosphate head and hydrophobic fatty acid tails

simple diffusion

movement of a solute from an area of high concentration to an area of low concentration

integral proteins

penetrate the hydrophobic interior of the lipid bilayer

peripheral proteins

bound to the surface of the membrane

Osmosis

Diffusion of water through a selectively permeable membrane

Aquaporins

water channel proteins

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

Glycoproteins

Membrane carbohydrates that are covalently bonded to proteins.

Glycolipids

Membrane carbohydrates that are covalently bonded to lipids.

fluid mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane

hydrophillic

outer portion of the cell membrane that loves water; outside of phospholipid bilayer

hydrophobic

inner portion of the cell membrane that fears water; inside of phospolipid bilayer

Cholesterol

A lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.

gated ion channels

ion channels that open or close in response to stimuli

sodium-potassium pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

facilitated diffusion

process of diffusion in which molecules pass across the membrane through cell membrane channels

cell adhesion molecules (CAMs)

surface proteins binding the cell to the extracellular matrix or to other cells

sodium dependent glucose transporter

Protein transporters found in the small intestine and the proximal tubule of the nephron. Sodium dependent glucose transporters contribute to renal glucose reabsorption.

vesicle formation and fusion

Vesicle-mediated transport in cells involves budding of vesicles from a donor membrane

Exocytosis

Process by which a cell releases large amounts of material

endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

nicotinic acetylcholine receptors

neurotransmitter that opens and closes a pore

Solvent

A liquid substance capable of dissolving other substances

Solute

A substance that is dissolved in a solution.

water potential

The physical property predicting the direction in which water will flow

concentration gradient

A difference in the concentration of a substance across a membrane

hypotonic solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution

hypertonic solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution

isotonic solutions

solutions separated by a membrane and containing an equal concentration of non-permeating solutes

Osmometer

instrument for measuring osmotic pressure