Presentation on theme: "Chapter 2 Cells– The Units of Life. Section 1- The World of Cells A. Cells help living creatures with activities of life such as movement, growth, and."— Presentation transcript:
Chapter 2 Cells– The Units of Life
Section 1- The World of Cells A. Cells help living creatures with activities of life such as movement, growth, and reproduction 1. The cell theory developed after Robert Hooke invented the microscope in 1865 a. All living things are made of one or more cells b. The cell is the basic unit of life c. All cells come from cells that already exist.
2. Bacteria are one-celled organisms; larger organisms are made of many cells, sometimes trillions of cells. 3. The term cell came from Robert Hooke in Looked at a thin slice of cork 2. The word ‘cells’ comes from the Latin word Cella, meaning a small room. 3. Hooke was the 1 st scientist to recogonize that living matter was built from basic units.
B. Cells are composed of parts that do specific jobs. 1. 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.
2. Cytoplasma- is a gelatin like substance containing may chemicals the cell needs. Cytoplasma 3. Specialized cell parts called organelles do various jobs within a cell. organelles 4. The nucleus contains the hereditary material called chromosomes. nucleus 5. Vacuoles are storage organelles for food, water, and wastes. Vacuoles
C. Inside the mitochondria, cellular respiration uses oxygen to convert food energy into a form the cell can use. mitochondria 1. Waste products of cellular respiration are carbon dioxide and water. 2. Leaf cell in plants contain chloroplasts that help the cell make its own food through photosynthesis. chloroplasts
Section 2 The Different Jobs of Cells A. The cells in many-celled organisms are specialized in shape and size for their function. 1. Human specialized cells include fat cells, bone cells, bone nerves, nerve cells, and muscle cells. a. Fat cells store so much fat that the nucleus is pressed against the cell membrane. Fat cells Fat cells b. A hard calcium and phosphorus material surrounds bone cells c. Nerve cells have many long branches to send and receive messages. d. Muscle cells have fibers that can contract and relax. 2. Plants cells in leaves, stems, and roots are specialized to move food and water or to support the plant.