1. Objective: 8.L.5.1 –Summarize how food provides the energy and molecules required for building materials, growth, and survival of all organisms.

2. All Living Things Share Four Characteristics of Life All living things have an ability to acquire materials and energy Living things are highly organized, from the smallest part to the largest All living things have an ability to respond to their environment All living things have an ability to reproduce

3. All Living Things Need energy 1.Carbohydrates 2.Proteins 3.Vitamins 4.Fats 5.Water 6.Minerals nutrientsPhotosynthesis 1.Sun’s energy 2.Water 3.carbon dioxide produces 4.glucose /sugar 5.oxygen Cellular Respiration 1. oxygen 2. glucose /sugar produces 3 Energy (ATP) 4. Water 5. carbon dioxide Respond to Environment 1.Diffusion 2.Osmosis Material moves in and Out of the cell

4. Ability to Respond to its environment

5. Molecules are always moving Molecules move randomly and bump into each other and other barriers Molecules in solutions tend to slowly spread apart over time. This is diffusion.

6. DIFFUSION Food, water, oxygen, carbon dioxide and other substances are made of different kinds of particles, such as molecules and ions.  Because these particles (molecules) are gradually spreading they are always moving, like dancers on a crowded dance floor.

7. What is Diffusion? Diffusion – the process by which molecules spread from areas of high concentration, to areas of low concentration.

8. Diffusion will continue until equilibrium is reached. This means there will be an equal distribution of molecules throughout the space. This is why food coloring moves throughout a beaker of water; why odors smell strong at first and then disappear over time. This process also occurs in the movement of material into or out of cells.

9. Why is diffusion important? All living cells rely on diffusion to get substances they needs to live. They use it for:  getting raw materials for respiration (dissolved substances and gases )  removing waste products (eg. from respiration )  photosynthesis in plants (raw materials in, waste products out ) Examples…  Moving nutrients in and out of the cell

10. Diffusion Through a Cell Membrane Cells also need food and water to live Substances move into and out of the cell through its cell membrane A cell membrane is like the cell’s skin.

11. Functions of Cellular Membranes 1. Protect cell 2. Control incoming and outgoing substances 3. Maintain ion concentrations of various substances 4. Selectively permeable - allows some molecules in, others are kept out

12. Diffusion and Respiration- gas exchange SEM photos of lung alveoli In breathing you exchange carbon dioxide (CO 2 ) and oxygen (O 2 ) between alveoli in the lungs and the blood. This is an example of diffusion.

13. Respiration- in cells food + oxygen  carbon dioxide + water + energy

14. Respiration & diffusion

15. Photosynthesis & Diffusion  Carbon dioxide diffuses in through the stomata  Oxygen and water diffuse out of the stomata carbon dioxide + water  oxygen + glucose

16. OSMOSIS Most of your body is made of water. This water can move into and out of your cells Water can enter and leave your cells by diffusion.  When water DIFFUSES through a CELL MEMBRANE, the process is called OSMOSIS.

17. Osmosis: diffusion of water through a selectively permeable membrane from a area of high concentration to an area of lower concentration. Water moves freely through pores. Solute (green) too large to move across. What is Osmosis?

18. Cell Membranes are Semi- permeable (selectively) Allows some substances into the cell, but screens out toxins and bacteria Substances allowed to cross include such as water, CO 2, Glucose, O 2, Amino Acids, Alcohol, and antihistamines.

19. Small molecules pass through – ex: water Large molecules can’t pass through – ex: proteins and complex carbohydrates

20. Hypotonic Solutions contain a low concentration of solute relative to another solution. Hypertonic Solutions contain a high concentration of solute relative to another solution. Factors that affect the rate of osmosis: size of molecules, size of pores in membrane, temperature, pressure, and concentration.

21. Over time molecules will move across the membrane until the concentration of solutes is equal on both sides. This type of solution is called ISOTONIC.

22. Study the diagram below. Which arrow shows the direction the solute molecules would move to achieve homeostasis?

23. If the membrane shown is permeable to molecules of X, but impermeable to molecules of Y, what will be the result of diffusion over time? A.Molecules of X on each side of the membrane will become equal in concentration. B.Molecules of Y on each side of the membrane will become equal in concentration. C.Molecules of X will increase in concentration on the right side. D.Molecules of Y will increase in concentration on the right side.

24. What determines the flow of materials in and out of the cell? Osmosis- diffusion of water through a selectively permeable membrane. There are 3 types of solutions: –Isotonic –Hypertonic –Hypotonic

25. Cytoplasm is a solution of water and solids (solutes dissolved in the water). Water moves into and out of cells because of the different concentrations of the solutes. Different kinds of cells react differently depending on the solution they are in. Below are examples of red blood cells in different types of solutions and shows what happened to the red blood cells.

26. Isotonic Solution Isotonic: The concentration of solutes and water inside the cell is equal to the concentration of solutes and water outside the cell. Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium) Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

27. Hypertonic Solution Hypertonic: concentration of solutes is greater therefore the concentration of water is lower outside the cell than the concentration of solutes and water inside the cell. (High solute; Low water) Result: Water moves from inside the cell into the solution: Cell shrinks -dehydration (Plasmolysis/crenation)! Osmosis Animations for isotonic, hypertonic, and hypotonic solutions shrinks

28. Hypotonic Solution Hypotonic: The concentration of solutes is lower therefore the concentration of water is higher outside the cell than inside the cell. (Low solute; High water) Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)! Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis Cell Swelling

29. Turgor Pressure builds in the cell and causes osmosis to stop because of the rigid cell wall. Plants will wilt when cells lose water through osmosis. Hypotonic Solution Hypertonic Solution PLANT CELLS

30. ELODEA CELLS As viewed under the microscope

31.  In the picture, water is diffusing through a cell membrane.  Why is the water moving INTO the cell in the picture? Water particles Outside of Cell Inside of Cell Cell Membrane

32. Because water has a lower concentration inside the cell than outside the cell. Water moves into the cell by OSMOSIS.

33. What happens to the raisin after sitting in the water for a while?  It becomes larger  Why does this happen?

34. Water molecules have a lower concentration inside the raisin. Outside the raisin, water molecules are crowded. Water molecules diffuse into the raisin by osmosis.

35. Methods of Transport Across Membranes 1. Diffusion 2. Osmosis 3. Facilitated Diffusion 4. Active Transport

36. PASSIVE TRANSPORT Passive transport occurs without expenditure of energy. Molecules move using their own kinetic energy. Diffusion and osmosis are examples of passive transport. Passive transport allows cells to get water, oxygen and other small molecules that they need. It also allows the cell to get rid of waste such as carbon dioxide. DIFFUSION OSMOSIS

37. Active vs. Passive Transport Passive Transport – does not require energy. Particles move from high to low concentration. Active Transport – does require energy because molecules are moving from low to high concentration

38. Methods of Transport Across Membranes 1. Diffusion -passive transport of molecules from an area of high concentration to an area of low concentration – no energy is used 2. Osmosis - Passive transport of water across membrane – no energy is used 3. Facilitated Diffusion - Use of proteins to carry polar molecules or ions across – energy used 4. Active Transport- requires energy to transport molecules against a concentration gradient – energy is used in the form of ATP

39. Cells Maintain Balance The cell controls its food and water content by moving ions, molecules, and larger particles into or out of itself. This is how the cell maintains homeostasis. Homeostasis Simulation http://trc.ucdavis.edu/biosci10v/bis10v/media/c h17/hot_guy.html Complete the Vocabulary Review

40. Endocytosis Some things the cells needs are too large to pass through the cell membrane. The cell membrane can surround a large particle located outside the cell.  The membrane forms a sac around the particle.  Then the sac opens inside the cell.

41. The sac moves to the membrane and then opens outside the cell. Waste particle move OUTSIDE the cell. This process of moving large particles OUT of the membrane is called EXOCYTOSIS. Large particle leave the cell in sacs too. Inside a cell, a sac forms around large waste particles.

42. Reviewing Vocabulary 1.Some substances move into and out of cells by diffusion. 2.The word concentration refers to how crowded particles are. 3.Some particles diffuse into and out of cells through the cell membrane 4.Particles tend to move toward places where they have a low concentration. 5.Particles tend to move away from places where they have a high concentration 6.Give one example of diffusion in your home. cooking, sugar in tea, ‘cut the cheese’

43. Vocabulary Review 1.One example of osmosis is water diffusing into a raisin. 2.Cells do not work to move molecules by passive transport. 3.Two forms of passive transport are osmosis and diffusion. 4.In diffusion and osmosis, particles move by themselves. 5.Water molecules tend to move to places where they have a low concentration. 6.Give one way that osmosis is similar to diffusion. Both move from high to low concentration.

44. Vocabulary Review 1.Cells use energy to move molecules by active transport. 2.Diffusion and osmosis are two kinds of passive transport. 3.Some molecules are too large to pass through the cell membrane. 4.Cells take in large molecules by endocytosis. 5.Cells must maintain a balance, called homeostasis.

45. THE END