1. Biology Unit 1 Notes: Types of Cells

2. (1) Types of Organisms Unicellular Organisms: Multicellular Organisms:
Organisms that are made of only one single cell.
The single cell completes all characteristics of life and maintains homeostasis on its own.
Multicellular Organisms:
Organisms made of many different types of specialized cells.
Each different body part / organ is made of different types of cells.
Each type of cell has a unique structure and function.
All of the different cells must work together to complete the characteristics of life, and homeostasis.

4. (2) Multicellular Organization
Smallest Level (Microscopic)
Atoms & Molecules
Cells (The basic units of life.)
Tissues (Similar cells working together on a common function.)
Organs (Different types of tissues working together on a common function.)
Organ Systems (Different types of organs working together on a common function.)
Organism (All organ systems working together to maintain homeostasis.)
Largest Level (Macroscopic)

6. (3) What is a cell? The cell is the most basic unit of living things.
The Cell Theory States that:
All living things must be made of at least one cell.
The cell is the basic unit of life.
New cells must come from old cells (pre-existing cells).

7. The Weird Theory of the Cell Theory

8. (4) Types of Cells Prokaryotic Cells: Eukaryotic Cells
Cells without a nucleus.
Example = Bacteria
Eukaryotic Cells
Cells with a nucleus.
Example = Plant + Animal Cells

9. Prokaryotic Cell

10. Eukaryotic Cell

11. Comparing Prokaryotic and Eukaryotic Cells
All cells have several basic features.
They are bounded by a plasma membrane.
They contain a semifluid substance called the cytosol.
They contain chromosomes.
They all have ribosomes.

12. Prokaryotic Cells Do not contain a nucleus
Are smaller than eukaryotic cells.
Lack internal structures
surrounded by membranes.

13. Eukaryotic cells
Contain a true nucleus, bounded by a membranous nuclear envelope
Are generally quite a bit bigger than prokaryotic cells

14. Eukaryotic vs. Prokaryotic
Eukaryotic Cell
Prokaryotic Cell
Nucleus
Present
None
Cell Wall
Only plant and fungi
Cell Types
uni- and multicellular
Unicellular
Organelles
Absent
Chromosomes
More than one; Linear
One; Circular
Cytoskeleton
present
absent
Examples
Animals, Plants, Fungi
Bacteria, Archea

15. The Three Domains of Life
At the highest level, life is classified into three domains
Bacteria
Archaea
Eukaryota

16. The Three Domains of Life
Domain Bacteria and domain Archaea
Prokaryotes
Domain Eukarya
Eukaryotes
Includes the protists and the kingdoms Plantae, Fungi, and Animalia