1. Seventh Grade1

2. 2 Moving Cellular Material A. Passive Transport 1.A cell membrane is semipermeable, which means that it allows only certain substances to enter and leave a cell. 2.Passive transport is the movement of substances through a cell membrane without using the cell’s energy.

3. Seventh Grade3 B. Diffusion 1.Diffusion is the movement of substances from an area of higher concentration to an area of lower concentration. 2.Usually diffusion continues through a membrane until the concentration of a substance is the same on both sides of the membrane.

4. Seventh Grade4 C. Osmosis-The Diffusion of Water 1.Osmosis is the diffusion of water molecules only through a membrane. 2.If the concentration of water in the air surrounding a plant is less than the concentration of water inside the plant’s vacuoles, water will diffuse into the air until the concentrations are equal.

5. Seventh Grade5 3. Facilitated diffusion allows molecules to pass through a cell membrane using transport proteins. a. Carrier proteins carry molecules through the cell membrane. b. Channel proteins allow ions to pass through the cell membrane.

6. Seventh Grade6 D. Active transport 1.Active transport uses cell’s energy to move substances through a cell membrane. 2.Active transport moves substances from areas of lower concentration to areas of higher concentration. 3.A cell uses endocytosis to take in a substance by surrounding it with the cell membrane.

7. Seventh Grade7 3.A cell uses endocytosis to take in a substance by surrounding it with the cell membrane. 4.A cell’s vesicles release their contents outside the cell during exocytosis.

8. Seventh Grade8 E.Cell Size and Transport 1.For a cell to survive, its surface area must be large compared to its volume. 2.As a cell grows, its volume increases faster than its surface area.

9. Seventh Grade9 Question: How do substances move into and out of cells?

10. Seventh Grade10 Substances can move into and out of cells by diffusion, osmosis, facilitated diffusion, endocytosis, and exocytosis

11. Cells and Energy Seventh Grade11

12. Seventh Grade12 Cells and Energy A. Cellular respiration 1. All living things need energy to survive. 2. Cellular respiration is a series of chemical reactions that convert the energy in food molecules into a usable form of energy called ATP.

13. Seventh Grade13 3. The first step of cellular respiration, called glycolysis, occurs in the cytoplasm of all cells. 4. During glycolysis glucose, a sugar, is broken into smaller molecules. 5. The second step of cellular respiration occurs in the mitochondria of eukaryotic cells. This step requires oxygen.

14. Seventh Grade14 6. During the second step of cellular respiration, the smaller molecules made during glycolysis are broken down. Large amounts of usable energy, called ATP, are produced. 7. Water and carbon dioxide (CO 2 ) are two waste products that are given off during the second step of cellular respiration.

15. Seventh Grade15 C. Fermentation 1. Eukaryotic and prokaryotic cells use fermentation to obtain energy form food when oxygen levels are low. 2. Fermentation occurs in a cell’s cytoplasm.

16. Seventh Grade16 3. Lactic-acid fermentation converts glucose into ATP and a waste product called lactic acid. 4. Some types of bacteria and yeast make ATP during alcohol fermentation. This process produces ethanol and CO 2.

17. Seventh Grade17 C. Photosynthesis 1. Plants and some unicellular organisms obtain energy from light. 2. Photosynthesis is a series of chemical reactions that convert light energy, water, and CO 2 into glucose and oxygen. 3. In plants, light energy is absorbed by pigments such as chlorophyll.

18. Seventh Grade18 4. The chemical reactions of photosynthesis occur in chloroplasts, the organelles in plant cells that convert light energy into food. 5. Photosynthesis uses CO 2 that is released during cellular respiration to make food energy and release oxygen.

19. 6. When an organism eats plant material, it takes in food energy. An organism’s cells use oxygen released during photosynthesis. Seventh Grade19

20. Seventh Grade20 Question: How are cellular respiration and photosynthesis related?

21. Seventh Grade21 Photosynthesis uses light energy and CO 2 that is released during cellular respiration to make food energy and release oxygen. When an organism eats plant material, it takes in food energy. An organism’s cells use oxygen released during photosynthesis and converts the food energy into usable energy through cellular respiration.