1. Prokaryote vs. Eukaryote A Cellular Comparison

2. Levels of Organization
= Living Organism

3. Life Can be Found in the Form of …
Single-cell organism
Multi-cell organism

4. A Brief History… Robert Hooke First light microscope.
Observed that cork was made of cells.

5. Anton van Leeuvenhoek
Used simple microscope to observe living organisms in water.

6. Characteristics of Living Things
Made of cells.
Obtain and use energy.
Grow and develop.
Reproduce.
Have a universal genetic code.
Change/evolve over time.
Respond to their environment.
Homeostasis: Maintain a stable internal environment.

7. What is the Cell Theory? Three Main Components:
All living things are composed of cells.
Cells are the basic unit of structure and function in living things.
New cells are produced from preexisting cells.

8. Overview of the Cell
A cell is the smallest part of an organism that retains characteristics of the entire organism.
For example, a cell can take in fuel, convert it to energy, and eliminate wastes, just like the organism as a whole can.
Because cells can perform all the functions of life, the cell is the smallest unit of life.

9. A Quick Review
Prokaryotes don’t have a “true” nucleus in their cells. Nor do they have organelles. Bacteria and archaea are all prokaryotes.
Eukaryotes have a nucleus in their cells that houses their genetic material. They also have organelles. Plants, animals, algae, and fungi are all eukaryotes.

10. Prokaryotic Cell

11. Prokaryotic Cells
The majority of prokaryotic cells share these characteristics:
A plasma membrane forms a barrier around the cell, and a rigid cell wall outside the plasma membrane provides additional support to the cell.
DNA, the genetic material of prokaryotes, is located in the cytoplasm, in an area called the nucleoid.
Ribosomes make proteins in the cytoplasm.
Prokaryotes break down food using cellular respiration (which requires oxygen) and another type of metabolism called fermentation (which doesn’t require oxygen).

12. Eukaryotic Cells: Animal Cells vs. Plant Cells

13. Eukaryotic Cells Eukaryotes have the following characteristics :
A nucleus that stores their genetic information.
A plasma membrane that encloses the cell and separates it from its environment.
Internal organelles, such as the endoplasmic reticulum and the Golgi apparatus, that create specialized compartments inside the cells.
A cytoskeleton made of proteins that reinforces the cells and controls cellular movements.

14. Eukaryotic Cells (cont.)
Eukaryotes have the following characteristics :
Organelles called mitochondria that combine oxygen and food to transfer the energy from food to a form that cells can use.
Organelles called chloroplasts, which use energy from sunlight plus water and carbon dioxide to make food. (Chloroplasts are found only in the cells of plants and algae.)
A rigid cell wall outside of their plasma membrane. (This is found only in the cells of plants, algae, and fungi; animal cells just have a plasma membrane, which is soft.

15. Cells and Organelles: Breaking it Down into Parts
Plant and animal cells are very similar, but they have a few significant differences in their organelles.
Plant cells have chloroplasts, large central vacuoles, and cell walls; animal cells don’t.
What animal cells do have that plant cells don’t are centrioles, small structures that are part of the cytoskeleton and appear during animal cell division.

16. Prokaryotic Cell

17. Breaking it Down: Prokaryotic Cell Specifics
Much smaller
More simple; single cell
No nucleus; contains genetic material (DNA)
Circular DNA; found in the cytoplasm
No membrane-bound organelles
Cell wall

18. Eukaryotic Cells

19. Breaking it Down: Eukaryotic Cell Specifics
Much larger
More complex; multi-cellular
Contains a nuclear envelope which contains genetic material (DNA)
Complex DNA: linear DNA packaged into chromatin found inside the nucleus
Contains membrane-bound organelles: specialized structures in the cytoplasm
Cell wall: found in plants

20. Breaking it Down: Characteristics Shared
Same basic metabolism
Plasma membrane to control what enters and leaves the cell
“Filled” with cytoplasm
Contain ribosomes to make protein
Contain DNA

22. Cell Differentiation
Not all cells in an organism are the same, they are specific to the job they must do… this is called cell differentiation.
Cells vary in size.
Cells vary in shape, remember, form follows function.
Nerve cells, cardiac cells, plant cells, bacterium, blood cells.
Organization: Most cells have organelles that perform a specific function within the cell.

23. And, finally … What does size have to do with it?
Prokaryotic cells are much smaller than eukaryotic cells. Why?
Smaller surface area to volume allows nutrients to easily and quickly reach inner parts of the cell.
Eukaryotic cells are larger and can not pass nutrients as quickly. They require specialized organelles to:
Carry out metabolism
Provide energy
Transport chemicals throughout the cell

25. A Comparison Prokaryote Eukaryote Smaller Simple structure
Circular DNA
Cell Wall
Single-Cell
No Membrane-bound Organelles
Eukaryote
More complex
Nuclear Envelope
Cell Wall (plants)
Multi-Cell
Membrane-bound Organelles
Complex DNA
Larger
DNA
Ribosomes
Cytoplasm
Similar Metabolism
Plasma Membrane
Mostly Bacteria
Plants & Animals