Objectives 7.1 The Cell-State the cell theory.

-Describe how the different types of microscopes work.

- Distinguish between prokaryotes and eukaryotes.

Lesson Overview Life Is Cellular

The Cell Theory The cell theory states:

1. All living things are made up of cells.2. Cells are the basic units of structure and function

in living things.3. New cells are produced from existing cells.

Lesson Overview Life Is Cellular

Light MicroscopesA typical light microscope allows light to pass through a specimen and uses two lenses to form an image.

Because light waves are scattered as they pass through matter, light microscopes can only magnify objects 1000x.

Lesson Overview Life Is Cellular

Electron Microscopes Electron microscopes offer much higher resolution than light microscopes. But MUST be used in a vacuum, so only NONLIVING specimens can be studied.

There are two major types of electron microscopes: transmission and scanning.

Lesson Overview Life Is Cellular

Transmission Electron Microscopes Transmission electron microscopes produce flat, two-dimensional images.

Mag ~ 50-1 mill. x$30,000- $500,000

Lesson Overview Life Is Cellular

Scanning Electron Microscopes Scanning electron microscopes produce three-dimensional images of the specimen’s surface.

Mag 1000-100,000x$150,000

Lesson Overview Life Is Cellular

Prokaryotes and EukaryotesEukaryotes are cells that enclose their DNA in a nucleus.

Prokaryotes are cells that do not enclose their DNA in nucleus.

Lesson Overview Life Is Cellular

Prokaryotic cells are generally smaller and simpler than eukaryotic cells.

The organisms we call bacteria are prokaryotes.

Prokaryotes

Lesson Overview Life Is Cellular

Eukaryotes Eukaryotic cells are generally larger and more complex than prokaryotic cells.

Most eukaryotic cells contain dozens of structures and internal membranes.

There are many types of eukaryotes: plants, animals, fungi and protists.