1. Cell Processes and Energy Photosynthesis Respiration Cell Division Cancer Table of Contents

2. Cell Processes and Energy Energy in Living Things -Every living thing needs energy. -The cells of living things need energy too. -The sun is the direct or indirect source of energy for most living things.

3. Cell Processes and Energy - Photosynthesis The sun is the source of energy for most living things Plants use energy from the sun to make food. The zebra gets energy from eating grass. The lion gets energy by feeding on the zebra. The sun is the direct source of energy. The sun is the indirect source of energy.

4. Cell Processes and Energy Photosynthesis -Photosynthesis is the process by which a cell captures energy in sunlight and uses it to make food. -Autotrophs —organisms that make their own food. Examples: Plants, some protists, some bacteria. -Two stages of photosynthesis:

5. Cell Processes and Energy - Photosynthesis *Stage 1: Chlorophyll captures the energy from sunlight.

6. Cell Processes and Energy *Stage 2: The captured light energy is used to produce sugar and oxygen from carbon dioxide and water.

7. Cell Processes and Energy -Water (H 2 O) enters the plant through the roots and travels to the leaves. -Carbon Dioxide (CO 2 ) enters the plant through stomata in the leaves.

8. Cell Processes and Energy -In the chloroplasts, water and carbon dioxide undergo several chemical reactions powered by the light energy. -The products are glucose and oxygen. -Glucose is used for food or stored in other forms to be used later.

9. Cell Processes and Energy -Some of the oxygen is used to break down the glucose molecules and release energy. -The rest is released to the atmosphere through the stomata.

10. Cell Processes and Energy The Photosynthesis Equation -Chemists use equations to summarize chemical reactions. -The equation for photosynthesis is: light energy 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2 Carbon Water Glucose Oxygen dioxide

11. Cell Processes and Energy End of Section: Photosynthesis

12. Cell Processes and Energy Cellular Respiration -Cellular Respiration is the process by which cells obtain energy from glucose. -The chemical bonds of the glucose molecule are broken to release energy. -All cells carry out respiration continuously. -Respiration happens in the mitochondria.

13. Cell Processes and Energy The Respiration Equation -The equation for respiration is: C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + energy Glucose Oxygen Carbon Water dioxide

14. Cell Processes and Energy Comparing Photosynthesis and Respiration -Photosynthesis and respiration can be thought of as opposite processes. -During photosynthesis, plants use carbon dioxide and release oxygen. -During respiration, organisms use oxygen and release carbon dioxide.

15. Cell Processes and Energy - Respiration -This keeps the levels of both gases constant in Earth’s atmosphere.

16. Cell Processes and Energy End of Section: Respiration

17. Cell Processes and Energy Fermentation -Fermentation provides energy for cells without using oxygen. *The amount of energy released from each sugar molecule is much less than the amount released during respiration.

18. Cell Processes and Energy Types of Fermentation -Two types of Fermentation: *Alcoholic Fermentation—occurs when yeast break down sugars. Alcohol, carbon dioxide and a small amount of energy are the products. Yeast is used by bakers and brewers.

19. Cell Processes and Energy *Lactic Acid Fermentation—occurs during very hard exercise. Muscles use oxygen faster than you can replace it so fermentation begins to supply additional energy. Lactic acid is produced and causes sharp pains.

20. Cell Processes and Energy Cell Division -Cells grow and divide through a process called the Cell Cycle. -Three main stages to the cell cycle: *Interphase—a period of cell growth, development, and DNA replication *Mitosis—division of the nucleus *Cytokinesis—cytoplasm (cell) division

21. Cell Processes and Energy Cells in your body that no longer divide, such as nerve and muscle cells, are always in interphase. Cells that actively divide, such as your skin cells go through the entire cycle. Striated muscle cells Skin (cheek) cells

22. Cell Processes and Energy - Cell Division This diagram shows that cells spend most of their time in Interphase.

23. Cell Processes and Energy Details of Interphase -Growth: the cell grows to its full size. -Replication: DNA is long, thin and inside the nucleus. It is called chromatin material and it begins to make a copy of itself. -Preparation: cell makes centrioles that will be used in division.

24. Cell Processes and Energy Interphase Chromatin material Centrioles

25. Cell Processes and Energy Details of Mitosis -The nucleus and its contents divide by the process of mitosis. -Mitosis happens in phases: *Prophase *Metaphase *Anaphase *Telophase

26. Cell Processes and Energy - Cell Division -In Prophase: chromatin condenses to form chromosomes. They are short, thick and double-stranded. The nuclear membrane disappears. Spindle fibers form.

27. Cell Processes and Energy Prophase

28. Cell Processes and Energy Metaphase -In Metaphase, chromosomes line up in the middle of the cell and attach to spindle fibers.

29. Cell Processes and Energy Anaphase -During Anaphase, the chromosomes split and are pulled by spindle fibers to opposite ends (poles) of the cell.

30. Cell Processes and Energy Telophase -During Telophase, the chromosomes again become long and thin. -Two new nuclei form and the cytoplasm is ready to divide.

31. Cell Processes and Energy Cytokinesis -Cytokinesis (division of the cytoplasm) occurs last, forming two new cells. -The two new cells are called daughter cells. -They are identical to the first cell and have the exact same number of chromosomes.

32. Cell Processes and Energy - Cell Division

33. Cell Processes and Energy Meiosis -Gamete cells (sperm and egg cells) are produced through a process known as meiosis. -Gamete cells are not identical to the parent cell. They only have ½ the number of chromosomes. -Just like body cells, gamete cells pass through interphase before they divide. -Just like mitosis, meiosis happens in phases. However, the cell divides twice.

34. Cell Processes and Energy Phases of Meiosis There are two divisions each with four phases. First Cell Division Second Cell Division Prophase I Prophase II Metaphase I Metaphase II Anaphase I Anaphase II Telophase I Telophase II

35. Human Chromosomes

36. Cell Processes and Energy Prophase I and Metaphase I In Prophase I, double- stranded chromosome pairs come together. In Metaphase I, the chromosome pairs line up in the middle of the cell and attach to spindle fibers.

37. Cell Processes and Energy Anaphase I and Telophase I In Anaphase I, chromosome pairs separate; reducing the number of chromosomes in each new cell to one-half. In Telophase I, the cell divides into two cells. Chromosomes are still double-stranded.

38. Cell Processes and Energy Prophase II and Metaphase II In Prophase II, the spindle fibers reappear. In Metaphase II, the chromosomes line up in the middle of the cell and attach to spindle fibers.

39. Cell Processes and Energy Anaphase II and Telophase II In Anaphase II, the chromosome strands separate and move towards the poles. In Telophase II the cell divides for the 2 nd time. The nuclear membrane reforms. Four gamete cells have been produced. Each with ½ the number of chromosomes.

40. Cell Processes and Energy - The Cell and Inheritance Meiosis End result is four gamete cells, each with half the number of chromosomes

41. Cell Processes and Energy Comparison: Meiosis vs. Mitosis

42. Cell Processes and Energy Fertilization -The full number of chromosomes is restored during fertilization —the joining of sperm and egg. -Zygote- first cell of a new organism. -Human gamete cells = 23 chromosomes - Human zygote cell = 46 chromosomes - After fertilization, a zygote goes through mitosis and the organism develops.

43. Cell Processes and Energy DNA *found in the nucleus of a cell *controls the cell’s activities through coded instructions. *Often called: “The blue-print for life”. -Chromosomes are made of DNA molecules -DNA – deoxyribonucleic acid

44. Cell Processes and Energy *Its structure was discovered in 1953 by James Watson and Francis Crick.

45. Cell Processes and Energy -DNA is described as a double- helix (twisted ladder). -The sides of the ladder are made of alternating sugar molecules and phosphate groups. -The rungs of the ladder are composed of four nitrogen bases: Adenine (A)Thymine (T) Guanine (G) Cytosine (C)

46. Cell Processes and Energy - Cell Division “A” pairs with “T” “G” pairs with “C” The order of these pairs determines your characteristics. Its your “genetic code”.

47. Cell Processes and Energy These base pairs split when DNA copies itself. The molecule unzips itself and each strand is copied. Making a new DNA molecule is like making a new zipper using the old zipper as a model. Watch!! While a zipper only has one kind of tooth, DNA has four; A, T, C and G.

48. Cell Processes and Energy The correct bases float in from the cytoplasm according to the pattern. The end result is two identical DNA molecules. The section of DNA that directs the making of a specific protein is called a gene.

49. Cell Processes and Energy - Cell Division

50. Cell Processes and Energy RNA -RNA—ribonucleic acid: carries the genetic codes for making proteins from the nucleus to the ribosomes. -It is single-stranded instead of double- stranded. -Uracil (U) replaces Thymine (T)

51. Cell Processes and Energy Protein Synthesis Click the Video button to watch a movie about protein synthesis. - The DNA Connection

52. Cell Processes and Energy -Two types are made: *Messenger RNA (mRNA) —made from DNA in the nucleus. It leaves the nucleus and attaches to a ribosome. It carries info for making a protein. *Transfer RNA (tRNA) —helps translate the message and assemble the amino acids needed to make the protein.

53. Cell Processes and Energy - The DNA Connection How Cells Make Proteins During protein synthesis, the cell uses information from a gene on a chromosome to produce a specific protein.

54. Cell Processes and Energy Protein Synthesis Activity Click the Active Art button to open a browser window and access Active Art about protein synthesis. - The DNA Connection

55. Cell Processes and Energy mRNA tRNA

56. Cell Processes and Energy End of Section: Cell Division

57. Cell Processes and Energy What is Cancer? -Cancer —a disease in which cells grow and divide uncontrollably, damaging the parts of the body around them. *Over 100 types of cancer *Can happen in almost any part of the body.

58. Cell Processes and Energy - Cancer Cancer begins when a mutation occurs in a cell. The mutated cell divides over and over producing a tumor. Cancer cells break off and spread.

59. Cell Processes and Energy Treating Cancer -Three methods: 1. Surgery—remove the tumor 2. Radiation—use beams of high energy waves to kill cancer cells. 3. Chemotherapy—use drugs to kill cancer cells.

60. Cell Processes and Energy Preventing Cancer -Three ways: 1. Don’t smoke 2. Eat healthy 3. Protect skin from bright sun

61. Cell Processes and Energy End of Section: Cancer