Cells

Chapter 7

cell – basic unit of all organisms

I. HistoryA. Before microscopes

-diseases thought to be caused by magic

B. After microscopes

-Robert Hooke – scientist who first observed cells

-he looked at cork (dead bark)

-saw geometric compartments and called them “cells”

II. Cell Theory

A. All organisms are composed of one or more cells.

B. The cell is the basic unit of structure and organization in all organisms.

C. All cells come from preexisting cells.

III. Microscopes

A. compound light microscope – uses light and a series of lenses to magnify objects in steps

- up to 1500X magnification

III. Microscopes…

B. electron microscope – uses a beam of electrons to magnify objects

- up to 500,000X magnification

- 3D possible

-view structures within

cells

IV. Cell Types

A. Prokaryotic cells

- have no nuclei

-have no membrane-bound organelles

-ex. bacteria; called “prokaryotes”

nucleus – control center of the cell; the central membrane-bound organelle that manages or controls cell functions

organelles – small, specialized structures within the cell

IV. Cell types…

B. Eukaryotic cells-have nuclei

-have membrane-bound organelles

-ex. people, all animals and plants

called “eukaryotes”

Video: Unicellular organisms http://www.teachersdomain.org/resources/tdc02/sci/life/stru/singlecell/index.html

Cell membrane

• Found in:• All cells

• Function:– Protection– Controls what enters

and leaves the cell

Cell wall

• Found in:• Plant cells (and fungi &

some bacteria)

• Function:– Protection, support

Nucleus

• Found in:• All cells except

prokaryotes

• Function:– Controls cell

activities – Contains the genetic

material of the cell

Nucleolus

• Found in:• All cells except

prokaryotes

• Function:– Found in cell’s

nucleus– Make ribosomes

Ribosome

• Found in:• All cells

• Function:– Makes proteins for

the cell

Endoplasmic Reticulum (ER)

• Found in:• All cells except prokaryotes

• Function:– Folded membrane that

carries material within the cell

Golgi apparatus

• Found in:• All cells except

prokaryotes

• Function:– Packages proteins

and ships them around the cell

Mitochondrion

• Found in:• All cells except

prokaryotes

• Function:– Breaks down

glucose to release energy

Chloroplast

• Found in:• Plant cells (and some

others, too)

• Function:– Photosynthesis

Vacuole

• Found in:• All cells (larger in plant

cells)

• Function:– Store food and

wastes

Lysosome

• Found in:• Animal and plant cells

• Function:– Digest old cell parts

Cytoplasm

• Found in:• All cells

• Function:– Gel-like fluid inside

cell– Protects organelles

and keeps them in place