Cells: the basic unit of lifeprokaryotes and eukaryotes

The cell theory grew out of the work of many scientists and improvements in the microscope.• Many scientists contributed to the cell theory.

The cell theory grew out of the work of many scientists and improvements in the microscope.• Many scientists contributed to the cell theory.• More was learned about cells

as microscopes improved.

The cell theory grew out of the work of many scientists and improvements in the microscope.• Many scientists contributed to the cell theory.• More was learned about cells

as microscopes improved.

Early studies led to the development of the cell theory.• The cell theory has three principles.

1. All organisms are made of cells.

Early studies led to the development of the cell theory.• The cell theory has three principles.

2. Cells are the basic unit of structure and function in all living things.

3. All existing cells are produced by other living cells.

All cells share certain characteristics.• Cells tend to be microscopic.

Bacterium(colored SEM; magnification 8800x)

All cells share certain characteristics.• Cells tend to be microscopic.• All cells are enclosed

by a membrane.

Bacterium(colored SEM; magnification 8800x)

cell membrane

All cells share certain characteristics.• Cells tend to be microscopic.• All cells are enclosed

by a membrane.• All cells are filled with

cytoplasm.

Bacterium(colored SEM; magnification 8800x)

cell membrane

cytoplasm

There are two cell types: eukaryotic cells and prokaryotic cells.

There are two cell types: eukaryotic cells and prokaryotic cells.• Eukaryotic cells have a

nucleus.nucleus

cell membrane

There are two cell types: eukaryotic cells and prokaryotic cells.• Eukaryotic cells have a

nucleus.• Eukaryotic cells have

organelles.

nucleus

cell membrane

organelles

There are two cell types: eukaryotic cells and prokaryotic cells.• Prokaryotic cells do

not have a nucleus or

organelles. nucleus

cell membrane

organelles

There are two cell types: eukaryotic cells and prokaryotic cells.• Both eukaryotes and prokaryotes

have DNA (universal genetic code).

nucleus

cell membrane

organelles

cytoplasm

DNA

DNA