Scanning Electron-looks at a samples surface

Transmission Electron-can look at internal structuresRemember….these two can only

be used to look at nonliving cells!

Diffusion/Osmosis/Active TransportChapter 7

Cellular Transport-Moves substances within the cell and moves substances into and out of the cell.

There are 3 ways: Diffusion Osmosis Active Transport

All Prokaryotic and Eukaryotic cells have one Thin flexible boundary between cell and

environment that helps control what enters and leaves the cell.

Gives the Cell Shape Maintains Homeostasis

It is Selectively Permeable meaning it allows some substances to enter cell while keeping others out! Think of it as a.…..Fish Net or Screen Door

Composed of a phospholipid bilayer Phospholipid consists of:

1. A glycerol backbone 2. 2 fatty acid chains 3. Phosphate group.

The phospholipids are arranged tail to tail. The bilayer includes cholesterol, proteins, and carbs.

The head is polar and therefore attracted to water (hydrophilic)

The two fatty acid tails are nonpolar and are hydrophobic.

Together the phospholipids look like a sandwich. With the fatty acids forming the interior and the phospholipid heads facing the watery environment found outside of cell.

The net movement of particles from an area where there are many particles to an area where there are fewer particles Therefore substances diffuse from an area of

high concentration to low concentration. EX. Food coloring dropped into beaker of

water/Perfume

3 Factors Concentration

Concentration is high, more particles collide, diffusion occurs more quickly

Temperature Temp increases, particles move faster, diffusion

is faster Pressure

Higher pressure, particles closer together, collide faster, diffuse faster

Uses transport proteins to move other ions and small molecules across the plasma membrane.

The proteins open and close to allow substances in and out of cells.

This requires no extra energy because particles are moving from area of high concentration to low concentration

4. 4. Active transportActive transport uses cellular energy to move uses cellular energy to move substances across a cell membrane. molecules move substances across a cell membrane. molecules move from LOW concentration to HIGH concentrationfrom LOW concentration to HIGH concentration- helps organisms maintain - helps organisms maintain homeostasishomeostasis

USES ENERGY (ATP)!

Exocytosis takes materials OUT of the cell.

EndocytosisEndocytosis carries materials INTO the cell. carries materials INTO the cell.Examples: Pinocytosis – when cells engulf water using the cell membrane Phagocytosis – when cells engulf large particles (food) using the cell membrane

Water passes freely into and out of a cell through the plasma membrane this is called Osmosis.

Solution is made up of 2 parts the solvent and the solute. The solute dissolves in the solvent.

Concentration of solution decreases when amount of solvent increases. (Think of sugar and water)

Isotonic- Cell has the same concentration of water and solutes like ions, sugars, proteins. Water still moves through plasma membrane but enters

and leaves at the same rate Ex. Blood

Hypotonic- when cell lower concentration of solute than water. More water outside cell and wants to move to from high concentration to low so water enters cell causing cell to swell.

Ex. Veggies

Hypertonic- concentration of solute is greater outside of cell than water. Water will move out of cell causing cell to wilt. Ex. Plants wilting

1. E 2.A 3.F 4.B 5.G 6.H 7.C 8.D 9.I 10.L 11.K 12.J