CELL TRANSPORT
Cells must get nutrients in & wastes out of the cell in order to stay alive. They have several methods of doing this. Some methods expend energy. Some do not. The _________________________ regulates what enters & leaves the cell & also provides protection & support. The cell membrane is a double-layered sheet called a _____________________________. The cell membrane is like a fluid-mosaic.
PASSIVE MECHANISMS – no cellular energy is required
1. ________________________ - molecules or ions spread from higher concentrations to lower concentrations – this continues until ____________________ is reached
2. ________________________ - glucose combines with a special protein carrier that helps pass it across the membrane (still from higher concentration to lower concentration)
3. ________________________ - water molecules diffuse from a higher to a lower concentration (water tends to diffuse toward the area of higher osmotic pressure)
Drawing 1: Drawing 2: Drawing 3:
Cell is _______________ Cell is _________________ Cell is ________
Solution is _______________ Solution is ________________ Solution is _____
Cell will _________________ Cell will __________________ Cell will ______
4. ____________________________ - molecules are forced through membranes by the hydrostatic pressure that is greater on one side of the membrane than on the other (this usually happens with blood vessels)
ACTIVE MECHANISMS – cellular energy is required
1. _________________________ - using carrier proteins to move substances from lower concentrations to higher concentrations (sugars, a.a.’s, ions)
2. _________________________ - molecules that are too large to enter a cell by diffusion enter by the formation of a vesicle - 2 Types:
a) ________________________ - “cellular eating” – takes in solids (common in white blood cells)
b) ________________________ - “cellular drinking” – takes in liquids (water)
3. ___________________________ - sends materials out of the cell
Organisms with only one cell are called _____________________ while organisms with many cells are called _______________________.
LEVELS OF ORGANIZATION
1. ________________________ - basic functional unit of life
2. ________________________ - group of similar cells that perform a particular function
3. ________________________ - groups of tissues working together
4. ________________________ - group of organs working together (11 in the body)