Unit 2 HB Cell Transport

Honors Biology

cell membrane

the semipermeable membrane surrounding the cytoplasm of a cell.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration. No energy.

Osmosis

Diffusion of water through a selectively permeable membrane. No energy required.

Facilitated Diffusion

Process of diffusion in which molecules pass across the membrane through cell membrane proteins. No energy is required.

active transport

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

ATP

(adenosine triphosphate) main energy source that cells use for most of their work. Needed for active transport

Filtration

An example of passive transport that is caused by 2 forces: gravity and pressure

Endocytosis

process by which a cell takes bulk material into the cell by infolding of the cell membrane and creating a vesicle

Exocytosis

Process by which a cell releases large amounts of material.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells. "Cell eating"

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes. "Cell Drinking"

Hypertonic

when comparing two solutions, the solution with the greater concentration of solutes (less water).

Water will leave a cell in this solution.

Hypotonic

when comparing two solutions, the solution with the lesser concentration of solutes (more water).

Water will go IN to a cell in this solution.

Isotonic

Having the same solute concentration as another solution. Ideal for animal cells

plant cells prefer _____ environments because the extra water goes into the central vacuole, resulting in the normal turgid state

Hypotonic

Equilibrium

Same solute concentration on either side of a membrane

passive transport

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

selectively permeable

a property of cell membranes that allows some substances to pass through, while others cannot

protein channels

proteins in the membrane whose role it is to pass molecules that cannot go through the membrane