3.1 Cell Theory KEY CONCEPT Cells are the Basic unit of life.

3.1 Cell Theory The cell theory grew out of the work of many scientists and improvements in the microscope. Many scientists contributed to the cell theory.

3.1 Cell Theory The cell theory grew out of the work of many scientists and improvements in the microscope. Many scientists contributed to the cell theory. More was learned about cells as microscopes improved.

3.1 Cell Theory The cell theory grew out of the work of many scientists and improvements in the microscope. Many scientists contributed to the cell theory. More was learned about cells as microscopes improved. The cell theory is a unifying concept of biology.

3.1 Cell Theory KEY CONCEPT Technology continually changes the way biologists work.

3.1 Cell Theory Imaging technologies provide new views of life. A microscope provides an enlarged image of an object. stoma –light microscopes (LM)

3.1 Cell Theory stoma – scanning electron microscopes (SEM) Imaging technologies provide new views of life. A microscope provides an enlarged image of an object. –light microscopes (LM)

3.1 Cell Theory - transmission electron microscopes (TEM) stoma – scanning electron microscopes (SEM) Imaging technologies provide new views of life. –light microscopes (LM) A microscope provides an enlarged image of an object.

3.1 Cell Theory Early studies led to the development of the cell theory. The Cell theory has three principles. –All organisms are made of cells.

3.1 Cell Theory Early studies led to the development of the cell theory. The Cell theory has three principles. –All organisms are made of cells. –All existing cells are produced by other living cells.

3.1 Cell Theory Early studies led to the development of the cell theory. The Cell theory has three principles. – –All organisms are made of cells. – –All existing cells are produced by other living cells. – –The cell is the most basic unit of life.

3.1 Cell Theory Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells. All cells share certain characteristics.

3.1 Cell Theory Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells. All cells share certain characteristics. – –Cells tend to be microscopic. Bacterium (colored SEM; magnification 8800x)

3.1 Cell Theory Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells. All cells share certain characteristics. – –Cells tend to be microscopic. – –All cells are enclosed by a membrane. Bacterium (colored SEM; magnification 8800x) cell membrane

3.1 Cell Theory Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells. All cells share certain characteristics. – –Cells tend to be microscopic. – –All cells are enclosed by a membrane. – –All cells are filled with cytoplasm. Bacterium (colored SEM; magnification 8800x) cell membrane cytoplasm

3.1 Cell Theory There are two cell types: eukaryotic cells and prokaryotic cells.

3.1 Cell Theory There are two cell types: eukaryotic cells and prokaryotic cells. Eukaryotic cells have a nucleus. nucleus cell membrane

3.1 Cell Theory There are two cell types: eukaryotic cells and prokaryotic cells. Eukaryotic cells have a nucleus. Prokaryotic cells do not have membrane- bound organelles. nucleus cell membrane organelles

3.1 Cell Theory There are two cell types: eukaryotic cells and prokaryotic cells. Prokaryotic cells do not have a nucleus. nucleus cell membrane organelles

3.1 Cell Theory There are two cell types: eukaryotic cells and prokaryotic cells. Prokaryotic cells do not have a nucleus. Prokaryotic cells do not have membrane-bound organelles. nucleus cell membrane organelles cytoplasm