An analogy is a way to understand new ideas by making a comparison. 1.2 Cells An analogy is a way to understand new ideas by making a comparison. A factory can be used as an analogy for the cell. Parts of the cell that allow the cell to survive are called organelles. Organelles take up about 5 to 30 percent of the cell. The rest of the cell consists of water. How is the Newo colony similar to a factory? See pages 22 - 24 (c) McGraw Hill Ryerson 2007

The Functions of Cell Organelles The cell membrane protects the cell and regulates the movement of particles in and out of the cell. Cytoplasm, the jelly-like substance within the cell, contains organelles, water, and other life supporting materials. The nucleus: controls all the activities within the cell. contains deoxyribonucleic acid (DNA). See page 25 (c) McGraw Hill Ryerson 2007

The mitochondria are the organelles that produce energy in the cell. When the cell changes chemical energy, in the food we eat, to energy the cell can use, it is called cellular respiration. The total of all the chemical reactions that take place in our cells is called our metabolism. See page 26 Cellular Respiration (c) McGraw Hill Ryerson 2007

Organelles for Assembly, Transport, and Storage Proteins are essential for all life and are assembled by the ribosomes. Proteins then pass through the endoplasmic reticulum and are placed in vesicles by the Golgi body. Vacuoles are temporary storage compartments. Lysosomes break down food particles, cell wastes, and worn-out organelles. See pages 28-29 (c) McGraw Hill Ryerson 2007

The Difference Between Plant and Animal Cells Plant cells have two parts that are not found in animal cells: Cell Wall protects the cell and gives cell shape Chloroplasts change the Sun’s energy into chemical energy Locate the cell wall and chloroplast See pages 29-30 (c) McGraw Hill Ryerson 2007 Photosynthesis

The cell is the basic unit of life. Cell Theory The cell is the basic unit of life. All organisms are composed of one or more cells. All cells come from other living cells. See pages 31-32 (c) McGraw Hill Ryerson 2007

Prokaryotic and Eukaryotic Cells Cells are classified into two groups: Prokaryotic cells have organelles that are not surrounded by membranes. Eukaryotic cells have organelles that are surrounded by membranes. Eukaryotic cells are usually larger than prokaryotic cells. See page 32 (c) McGraw Hill Ryerson 2007

Bacteria and Viruses Bacteria are prokaryotic cells. Some bacteria cause diseases such as: tuberculosis and strip throat. Helpful bacteria are used to make food such as: cheese and yogurt. Bacteria are often grouped by the shape of their cells. Viruses are not living. HIV, chicken pox, and the flu are examples of viruses. Viruses do not contain any cell organelles but reproduce by using a host cell. See pages 33 - 34 (c) McGraw Hill Ryerson 2007 Take the Section 1.2 Quiz