1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment Bellringer Which of the following best describes a living cell: a) building block b) a living organism c) a complex factory d) all of the above Write a paragraph in your science journal defending your choice. Chapter 4

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment What Is Diffusion? Diffusion is the movement of particles from regions of higher density to regions of lower density. Diffusion of Water The diffusion of water through cell membranes is called osmosis. Chapter 4

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment What Is Diffusion?, continued The Cell and Osmosis Osmosis is important to cell functions. Plasma surrounds red blood cells and is made up of water, salts, sugars, and other particles. Osmosis keeps the concentration of these particles in balance. When a wilted plant is watered, osmosis makes the plant firm again. Chapter 4

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment Moving Small Particles Passive Transport The movement of particles across a cell membrane without the use of energy by the cell is called passive transport. Active Transport A process of transporting particles that requires the cell to use energy is called active transport. Chapter 4

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment Chapter 4

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment Moving Large Particles Endocytosis The active-transport process by which a cell surrounds a large particle and encloses the particle in a vesicle to bring the particle into the cell is called endocytosis. Exocytosis The process in which a cell releases a particle by enclosing the particle in a vesicle that then moves to the cell surface and fuses with the cell membrane is called exocytosis. Chapter 4

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Exchange with the Environment Chapter 4

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Energy Bellringer Make a list of all the different types of cells that you can think of and the jobs they do. Then make a list of all the reasons that a cell needs energy. Write your answers in your science journal. Chapter 4

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Energy From Sun to Cell Photosynthesis is the process by which plants, algae, and some bacteria use sunlight, carbon dioxide, and water to make food. Chlorophyll Plant cells have molecules that absorb light energy. These molecules are called pigments. Chlorophyll, the main pigment used in photosynthesis, gives plants their green color. Chapter 4

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Energy From Sun to Cell, continued Chapter 4

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Energy Getting Energy from Food Cellular Respiration During cellular respiration, food (such as glucose) is broken down into carbon dioxide and water, and energy is released. Chapter 4

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Energy Getting Energy from Food, continued Connection Between Photosynthesis and Respiration During photosynthesis, cells take in carbon dioxide and release oxygen. During cellular respiration, cells use oxygen to break down glucose and release energy and carbon dioxide. Fermentation When muscles can’t get the oxygen for cellular respiration, they use fermentation to get energy. Fermentation is the breakdown of food without the use of oxygen. Chapter 4

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Cell Energy Chapter 4

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 The Cell Cycle Bellringer Biology is the only science in which multiplication means the same thing as division—at least with regards to cells. Explain what is meant by this statement in your science journal. Chapter 4

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 The Cell Cycle The Life of a Cell The cell cycle begins when the cell is formed and ends when the cell divides and forms new cells. Before a cell divides, it must make a copy of its DNA which is organized into structures called chromosomes. Chapter 4

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 The Cell Cycle The Life of a Cell, continued Making More Prokaryotic Cells Cell division in bacteria is called binary fission, which means “splitting into two parts.” Bacteria have a single circular DNA molecule (chromosome). Binary fission results in two cells that each contain one copy of the circle of DNA. Chapter 4

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 3 The Cell Cycle The Life of a Cell, continued Eukaryotic Cells and Their DNA The chromosomes of eukaryotic cells contain more DNA than those of prokaryotic cells. In a eukaryotic cell, chromosomes are found in the nucleus and are made of DNA and protein. Pairs of similar chromosomes are called homologous chromosomes. Chapter 4

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 The Cell Cycle The Life of a Cell, continued Making More Eukaryotic Cells The cell cycle has three stages: 1.Interphase: The cell grows and copies its chromosomes. The two copies are now called chromatids. 2.Mitosis: The chromatids separate. 3.The cell splits into two identical cells. Chapter 4

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 The Cell Cycle Mitosis and the Cell Cycle Mitosis has four phases: 1.prophase 2.metaphase 3.anaphase 4.telophase Chapter 4

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 3 The Cell Cycle Mitosis and the Cell Cycle, continued Cytokinesis is the division of cytoplasm. In animal cells and other eukaryotes that do not have cell walls, division of the cytoplasm begins at the cell membrane. In plant cells and in other eukaryotes with cell walls, a cell plate forms and the cell splits into two cells. Chapter 4