Introduction to Cells
Unit 3
In your own words tell me what you
already know about cells (5 complete
sentences).
Quizlet
1. Cell- basic unit of life
2. Cell membrane- thin flexible barrier that separates the cell
from its environment
3. Cell theory- theory that all living things are made of cells,
cells are the basic units of structure and function, and new cells
come from previously existing cells
4. eukaryote- cell with DNA that is enclosed in a nucleus
5. nucleus- cell structure that contains genetic material
6. prokaryote- cell with DNA not enclosed in a nucleus
What is a cell?
Cells are the basic unit of all life.
Cells are full of working parts called
organelles, that perform their own jobs.
Cells are the smallest unit in any
organism.
Cell Theory
The Cell Theory is an important concept
in Biology. It 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 come from existing cells.
Living organisms can be made up of one
cell or millions of cells.
• Unicellular- organisms that consist of
only one cell.
• Multicellular- organisms that consist of
many cells
Examples of Unicellular
Organisms
Bacteria: E. Coli are a mostly friendly bacteria
that live in the intestines of humans.
Amoeba:
A Pond water predator that eats other
unicellular organisms.
Examples of Multicellular
Organisms
Animals: Mammals, Fish, Reptiles
Plants: Flowers, Grasses, Trees
Cell Types
There are two broad cell type categories:
1. Prokaryotic- cells that do not enclose DNA in a nucleus.
2. Eukaryotic- cells that enclose DNA in a nucleus.
Prokaryotic Cells
First cell type on earth
No membrane bound nucleus
Prokaryotic Cells are smaller and simpler than eukaryotic
cells.
Nucleoid = region of DNA concentration
Organelles not bound by membranes
Example of Prokaryotic Cell: Bacteria
Prokaryotic Cell
Eukaryotic Cells
Eukaryotic Cells are larger and more complex than
Prokaryotic Cells.
Nucleus bound by membrane
Possess many organelles.
Types of Eukaryotic Cells: Animal and Plant Cells
Eukaryotic Cells
Prokaryotes vs Eukaryotes