A. Microscopy1. Parts:

a. The ocular or eyepiece allows you to view the objectsb. The objectives are the revolving nosepieces on thecompound microscope

-the scanning lens has the lowest power (~3-5x) -the low power lens is the intermediate power (10x)-the high power lens has the highest power (40-45x)

c. The stage is where you place the glass slides with your specimen

e. The fine and coarse adjustment knobs bring the specimen into focus by moving the focal plane

4X ocular multiplied by 40X objective = 160

3. Types of Microscopes

a. Stereomicroscope—also called dissecting microscope; used to see the largest field of view and whole organisms

b. Compound Microscope—most typical type used in science; usually magnifies up to 40x or even 60x

c. Electron microscope—uses electron beams to image; can visualize the smallest things; used to see inside organelles— nanometer scale

Stereoscope Image• How a spider might look through a dissecting scope

Compound Microscope Image•A rotifer typically found in pond water

Electron Microscope Image• A collection of pollen grains shown here

Cell Structure & FunctionCell Structure & Function

Plant and Animal Cell

B. Organelles of the Cell1. The Nucleus & Nucleolus

a. Nucleus: contains chromosomes (made of DNA)and the nucleolus

b. Nucleolus: the dark staining, dense cluster of proteins andnucleic acids where ribosomes are made

Nucleolus

4. Cell membranes, cell walls, and vacuolesa. The cell membrane surrounds the cell in order to protect it from

the outside environment

b. The cell membrane is made up of a phospholipid bilayer.

c. The cell wall is a rigid, protective layer on the outside of thecell membrane

d. Vacuoles are membrane-bound sacs of fluid in the cytoplasmwhich are used for storage. These can be especially large in plantcells.

Cell Wall& Membrane

Vacuole

Chloroplast

5. Chloroplasts a. Chloroplasts contain chlorophyll (green pigment)

b. Chloroplasts are the site of photosynthesis in plants

c. The grana are stacks of membrane bound disks found inside the chloroplasts.

d. The stroma is the fluid inside the chloroplast surrounding the

stacks of grana

Image from Ebiomedia.com

6. Mitochondriaa. The mitochondrion (sing.) is known as the “powerhouse

of the cell” because metabolism takes places here

b. Note the finger-like folds of the cristae to increasesurface area within the inner membrane

Cristae

Lysosomes – Cleaning Crew

• Lyse (to cut)

• Digestive compartments

Osmosis & DiffusionOsmosis & Diffusion

Learning Through Osmosis?

III. Osmosis and Diffusion1. Solutes & Solvents

a. Solutes are the substances dissolved in a liquidb. A solvent is a liquid in which the solute is being dissolvedc. The solute and solvent come together to make a solution

“I’m a solution! OOOOH YEAH!”

2. Diffusiona. Diffusion is the movement of molecules (usually solute) from areas of high concentration low concentration

4. Importance of Osmosis & Diffusion to Plantsa. central vacuole + cell wall = turgor pressure b. a plant cell is turgid when the central vacuole is distended withwater and presses up against the cell wallc. a plant cell is flaccid when water has left the central vacuoleand turgor pressure is low

Pond Water Salt Water Distilled Water

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