1. Lesson Overview
7.1 Life is Cellular

2. THINK ABOUT IT
What’s the smallest part of any living thing that still counts as being “alive?”
Can we just keep dividing living things into smaller and smaller parts, or is there a point at which what’s left is no longer alive?
As you will see, there is such a limit. The smallest living unit of any organism is the cell.

3. The Discovery of the Cell
What is the cell theory?
The cell theory states:
- All living things are made up of cells.
- Cells are the basic units of structure and function in living things.
- New cells are produced from existing cells.

4. Early Microscopes and the Cell Theory
1665 – Robert Hooke – Compound Microscope
First to identify cells
Same time period – Anton van Leeuwenhoek
First to observe living microorganisms
1838 – Matthias Schleiden (German botanist)
Plants are made of cells
1839 – Theodor Schwann (German biologist)
All animals are made of cells
1855 – Rudolf Virchow (German physician)
New cells only from division of existing cells (Lorenz Oken 50 years earlier)

5. Virchow contribution to the cell theory had to do with
Cell structure
Cell membranes
Cell reproduction
Cell size of 26 45
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6. Who stated that all animals are made of cells
Robert Hooke
Matthias Schleiden
Rudolf Virchow
Theodor Schwann of 26 45
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7. Cell Theory So once again, What is the cell theory?
The cell theory states:
All living things are made up of cells.
Cells are the basic units of structure and function in living things.
New cells are produced from existing cells.

8. Which of the following is not part of the cell theory?
All living things are made of cells
Basic units of structure and function
Plants and animals are made of cells
Cells come from existing cells of 26 45
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9. Cells are the basic units of life.
True
False of 26 45
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10. Prokaryotes and Eukaryotes
How are prokaryotic and eukaryotic cells different?
Prokaryotic cells do not separate their genetic material within a nucleus.
In eukaryotic cells, the nucleus separates the genetic material from the rest of the cell.

11. Prokaryotes and Eukaryotes
Cells are amazingly diverse.
Size varies (typically 5-50 micrometers)
0.2 microns – 1000 microns
All Cells have DNA
All Cells have a cell membrane (thin flexible barrier)
Cells may or may not have a nucleus (nuclei)
Contains genetic material, has membrane
Whether or not they have a nucleus determines whether they are prokaryotes or eukaryotes.

12. In many cells the structure that controls the cell is the….
Cell membrane
Nucleolus
Nucleus
Cytoplasm of 26 45
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13. Prokaryotes and Eukaryotes
Eukaryotes are cells that enclose their DNA in nuclei.
Prokaryotes are cells that do not enclose DNA in nuclei.

14. Prokaryotes
Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
Despite their simplicity, prokaryotes grow, reproduce, and respond to the environment, and some can even move by gliding along surfaces or swimming through liquids.
The organisms we call bacteria are prokaryotes.

15. Eukaryotes Eukaryotic cells are generally larger and more complex.
Most eukaryotic cells contain dozens of structures and internal membranes. Many eukaryotes are highly specialized.
There are many types of eukaryotes: plants, animals, fungi, and organisms commonly called “protists.”

16. Which of the following is true of a eukaryote but not a prokaryote?
Genetic material is in a nucleus
It has genetic material
Generally smaller and simpler
Carries out all activities of living things of 26 45
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17. Even though cells are different sizes and shapes they all have DNA and
A nucleus
A cell membrane
A cell wall
Ribosome of 26 45
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