1. Cells– The Units of Life
Chapter 2
Cells– The Units of Life

2. Section 1- The World of Cells
Cells help living creatures with activities of life such as movement, growth, and reproduction
The cell theory developed after Robert Hooke invented the microscope in 1865
All living things are made of one or more cells
The cell is the basic unit of life
All cells come from cells that already exist.

3. The term cell came from Robert Hooke in 1865
Bacteria are one-celled organisms; larger organisms are made of many cells, sometimes trillions of cells.
The term cell came from Robert Hooke in 1865
Looked at a thin slice of cork
The word ‘cells’ comes from the Latin word Cella, meaning a small room.
Hooke was the 1st scientist to recogonize that living matter was built from basic units.

4. Cells are composed of parts that do specific jobs.
The flexible cell membrane is the boundary of the cell and helps control what enters and exits the cell; some plant cells have a cell wall that helps support and protect the cell.

5. Cytoplasma- is a gelatin like substance containing may chemicals the cell needs.
Specialized cell parts called organelles do various jobs within a cell.
The nucleus contains the hereditary material called chromosomes.
Vacuoles are storage organelles for food, water, and wastes.

6. Cytoplasm
Nucleus

7. Cytoplasm
Vacuoles

9. Inside the mitochondria, cellular respiration uses oxygen to convert food energy into a form the cell can use.
Waste products of cellular respiration are carbon dioxide and water.
Leaf cell in plants contain chloroplasts that help the cell make its own food through photosynthesis.

10. Chloroplasts
Mitochondria

11. Section 2 The Different Jobs of Cells
The cells in many-celled organisms are specialized in shape and size for their function.
Human specialized cells include fat cells, bone cells, bone nerves, nerve cells, and muscle cells.
Fat cells store so much fat that the nucleus is pressed against the cell membrane.
A hard calcium and phosphorus material surrounds bone cells
Nerve cells have many long branches to send and receive messages.
Muscle cells have fibers that can contract and relax.
Plants cells in leaves, stems, and roots are specialized to move food and water or to support the plant.

12. Fat cells
Fat Cell
Nucleus

13. Cell Wall
Chloroplasts
Permenant Vacoule