Biology Unit 2 Notes: Cells

1. Biology
Unit 2 Notes:
Types of Cells

2. (1) Types of Organisms
• Unicellular 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. (4) Types of Cells
• Prokaryotic Cells:
• Cells without a nucleus.
• Example = Bacteria
• Eukaryotic Cells
• Cells with a nucleus.
• Example = Plant + Animal Cells

8. (5) Plant vs Animal Cells
• Because Plants and Animals are different types of organisms, their body parts
must carry out different types of functions.
• The following are things unique to only plant OR animal cells:
PLANT CELLS ANIMAL CELLS
Cell Wall Peroxisomes
Chloroplasts
Enlarged Vacuoles