Cell Theory and Body Systems Notes
Biology: The Cell & Body Systems Exam Notes
The Cell Theory
- All living things are made up of one or more cells.
- Unicellular: Organisms consisting of one cell.
- Multicellular: Organisms consisting of more complex cells.
- All cells come from pre-existing cells.
- Cells arise through cell division, not spontaneously.
- The cell is the most basic (smallest) unit that carries out all life processes.
- Cells perform all characteristics of living things.
- All living things are either prokaryotic or eukaryotic.
Prokaryotes/Prokaryotic Cells
- Lack membrane-bound organelles.
- Organelles are not surrounded by a double layer of fat/membrane.
- Simple and small structure.
- Less complex compared to eukaryotic cells.
- Fewer organelles than eukaryotes.
- All prokaryotic organisms are unicellular.
- DNA is free-floating in the cell.
- Located in the nucleoid region (no true nucleus).
- Examples:
- Bacteria:
- Archaea:
- Extremophiles: Organisms that thrive in extreme conditions.
Eukaryotes/Eukaryotic Cells
- Cells have more complex structures and organization.
- Organelles exist to aid cell function.
- Possess membrane-bound organelles.
- Larger than prokaryotic cells.
- Can be either unicellular or multicellular.
Four Kingdoms of Eukaryotes
- Protists
- Unicellular (less complex)
- Examples: Algae, Amoeba
- Fungi
- Multicellular
- Examples: Mushroom, Fungus
- Plants
- Multicellular
- Examples: Rose, Grass, Tree
- Animals
- Multicellular
- Examples: Humans, Dogs
Similarities Between Cells
Organelles