CHAPTER 3 CELLS 3.1 Cell Theory. KEY CONCEPT Cells are the Basic unit of life.
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Transcript of CHAPTER 3 CELLS 3.1 Cell Theory. KEY CONCEPT Cells are the Basic unit of life.
CHAPTER 3 CELLS3.1 Cell Theory
KEY CONCEPT Cells are the Basic unit of life.
Discovery of Cells
• The cell theory grew out of the work of many scientists and improvements in the microscope.
• A cell is the smallest unit capable of carrying out life functions
• More was learned about cells as microscopes improved.
• The cell theory is a concept of biology.
Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria
Wacky theory of cell history• Cell Theory
Discovery of Cells
• Zacharias Jannsen
• Man who invented the compound microscope
Discovery of Cells
• Robert Hooke• In 1665 he used a
microscope to look at a thin slice of cork
• Responsible for naming cells after looking at cork
• Named them after the chambers that monks lived in
Discovery of Cells
• Anton van Leeuwenhoek
• In 1674, first scientist to observe and describe living cells from looking at pond water
• Called them
Animalcules
The Cell Theory
• Matthias Schleiden• German Scientist• 1838, concluded all
plants are made of cells• Cofounded the Cell
Theory
The Cell Theory
• Theodore Schwann• German Zoologist • 1839, concluded all
animals were made of cells
• Cofounder of cell theory
The Cell Theory
• Rudolph Virchow• German Scientist• 1855, concluded all cells
come from other cells• Cell Division
Cell Theory
• 3 major principles of the Cell Theory1. All organisms are
made of cells
2. All existing cells are produced from other living cells
3. The cell is the most basic unit of life
• There are two types of cells: Prokaryote and Eukaryote• All cells share certain characteristics.
• Cells tend to be microscopic.• All cells are enclosed by a membrane which regulates the flow of
materials into and out of the cell.• All cells are filled with cytoplasm – a jelly like
substance containing dissolved molecules
like proteins and minerals.
Bacterium(colored SEM; magnification 8800x)
cell membrane
cytoplasm
There are two types of Cells: Prokaryotes and Eukaryotes• Prokaryotes
• Do not have a nucleus.• DNA in cytoplasm• Do not have membrane-bound
organelles• Single celled organisms• Less complex
Ex Bacteria
cell membrane
cytoplasm
There are two types of Cells: Prokaryotes and Eukaryotes• Eukaryotes
• Have a nucleus.• DNA in nucleus• Eukaryotic cells have
membrane-bound organelles.• Single or Multicellular• More complex and
Specialized Ex. Most plant and
animal cells
nucleus
cell membrane
organelles