Cells, Cells, Cells

Active Transportand

Passive Transport

Active transport is the movement of solutes and molecules across the cell membrane WITH the use of energy (ATP – adenosine tri-phosphate) by the molecule

Active Transport

There are different types of active transport that occurs in cells:

Endocytosis – the process of taking material INTO the cell by means of in-foldings, or pockets, of the cell membrane

Active Transport

Exocytosis – is the process of releasing material from the cell by means of small vesicles (bubble-like membranous structure)

Active Transport

Active Transport

Passive transport is the movement of solutes and molecules across the cell membrane WITHOUT the use of energy (ATP – adenosine tri-phosphate) by the molecule

Passive Transport

Also includes facilitated

diffusion of larger molecules through a protein

channel

Diffusion – the movement of substances from an area of high concentration to areas of low concentration

Passive Transport

Shows the random movement of small molecules down (with) the

concentration gradient until molecules are evenly dispersed

(in equilibrium)

Examples of small molecules: carbon dioxide, oxygen, small

non-polar molecules

Facilitated diffusion – the movement of substances with their concentration gradient (high to low concentration) through protein channels in the cell membrane

Passive Transport

Osmosis – the movement of water across a semi-permeable membrane from an area of high concentration to an area of low concentration

Passive Transport

a. Water moves from hypotonic to hypertonic solutions

Passive Transport

b. Water moves in equilibrium (equal amounts) in both directions across a membrane with isotonic solutions

Passive Transport

Factors that affect the movement of substances by passive transport include: temperature; size of the molecule; whether molecule is a solid, liquid, or gas; and concentration amount