1. CELL PROCESSES Part of AS91156

2. Transport Passive Transport Active Transport

3. Passive Transport Particles move along a concentration gradient around, into or out of the cell by the process of diffusion and without any energy expenditure by the cell. Examples: osmosis, plasmolysis and facilitated diffusion.

4. Diffusion Spreading of a substance by the movement of particles along a concentration gradient.

5. Diffusion through a membrane Cell membrane Inside cell Outside cell

6. Diffusion through a membrane Cell membrane Inside cell Outside cell diffusion

7. Diffusion through a membrane Cell membrane Inside cell Outside cell EQUILIBRIUM

8. Osmosis Movement of water from a high concentration [of water] to a low concentration [of water] through a semi-permeable membrane.

9. Plasmolysis in Plant Cells If enough water leaves a plant cell the cell membrane shrinks away from the cell wall. The cell is said to be plasmolysed.

10. Plasmolysed Oxygen Weed Cells

11. Turgid Oxygen Weed Cells

12. Facilitated Diffusion Movement of selected types of particles across the membrane along the concentration gradient. Faster than diffusion. Movement is aided by transport proteins in the membrane.

14. Active Transport The use of energy by the cell to move particles into or out of the cell against the concentration gradient. Examples: exocytosis, endocytosis and ion pumping.

15. Exocytosis Vesicles from golgi bodies or the endoplasmic reticulum expel their contents to the outside through the cell membrane.

16. Endocytosis: Pinocytosis Absorption of liquids into vesicles formed from part of the cell membrane. (Cell drinking.)

17. Endocytosis: Phagocytosis Absorption of solids into food vesicles formed from part of the cell membrane. (Cell eating.) Lysosomes then fuse with food vacuoles to digest particles.

18. Ion Pumping Ion pumps are proteins that move ions across a membrane against their concentration gradient.

19. Sodium Potassium Nerve Cell Pump

20. Cell Division

21. MITOSIS Cells divide to provide new cells for growth

22. MITOSIS Cells divide to repair damaged tissues

23. MITOSIS Cells divide to keep a large surface area to volume ratio.

24. The Cell Cycle

25. Deoxyribonucleic Acid

26. Bases: adenine, thymine, guanine, cytosine Double helix Function: genetic memory

27. DNA Base Pairing

29. Semi-conservative DNA Replication 1

30. Semi-conservative DNA Replication 2

31. Semi-conservative DNA Replication 3

33. Mitosis Photomicrographs

34. Interphase

35. Early Prophase

36. Late Prophase

37. Metaphase

38. Anaphase

39. Telophase

40. Cytokinesis

41. Centrioles Made from two hollow cylinders at right angles to each other. Forms spindle fibres to separate chromosomes in mitosis.

42. Enzyme Activity

43. Enzyme Structure Enzymes are Globular Proteins.

44. Amino Acid

45. Three Different Amino Acids

46. 1 o Protein Structure: a chain of amino acids

47. Enzyme: Beef Ribonuclease

48. 2 o Protein Structure Alpha Helix

49. 3 o Protein Structure Folded Helix

50. Enzymes Biological catalysts that speed up metabolic reactions Globular proteins Can be reused. Name often ends in -ase. Act on chemicals called substrates.

51. Enzyme Specificity Examples EnzymeSubstrate AmylaseAmylose (starch) PepsinProtein LipaseLidpid (fat) NucleaseNucleic acid SucraseSucrose (table sugar) LactaseLactose (milk sugar)

52. Enzyme Specificity

53. Lock and Key Model 1 All enzymes have active sites. The lock is the enzyme The key is the substrate. Only the correct key (substrate) fits into the key hole (active site) of the lock (enzyme).

54. Lock and Key Model 2

55. Induced Fit Model The enzyme changes shape on to fit the substrate only after binding to the substrate.

56. Enzymes as Catalysts Enzymes lower the activation energy.

57. Speed of enzyme controlled reactions depends on Temperature pH Concentration Co-factors

58. Effect of Temperature

59. Effect of pH 1

60. Effect of pH 2

61. Effect of Substrate Concentration

62. Effect of Co-factors Co-factor examples: Ca 2+, Mg 2+, Vitamin K, Vitamin B1, folic acid

63. Enzyme Inhibitors Examples of inhibitors: mercury, cadmium, lead, arsenic

64. Cellular Respiration C 6 H 12 O 6 + 6O 2  6H 2 O + 6CO 2 + energy

65. ATP: Adenosine triphosphate

66. Hydrolysis of ATP

67. Respiration: Glycolysis (1)

68. Respiration: Glycolysis (2)

69. Conversion of pyruvate to Acetyl-CoA

70. Mitochondrion

71. Respiration: Kreb Cycle (matrix)

72. Respiration: Respiratory Chain (cristae lining) Each FADH 2 produces 2ATP and regenerates FAD. Each NADH 2 produces 2ATP and regenerates NAD. Hydrogen combines with oxygen to form water.

74. Anaerobic Respiration Without oxygen the respiratory chain stops so NAD and FAD are not regenerated. Pyruvate enters an anaerobic pathway to produce some ATP and regenerate some NAD.

75. Anaerobic Respiration Lactic Acid Fermentation

76. Anaerobic Respiration Ethanol Fermentation

77. Comparing Aerobic and Anaerobic Energy Yeilds Yield ATPYield Kilo joule Aerobic Respiration 362880 Lactic Acid Fermentation 2150 Ethanol Fermentation 2210

78. Photosynthesis light energy + 6H 2 O + 6CO 2  C 6 H 12 O 6 + 6O 2

81. Photosynthesis Summary

82. Photosynthesis: Light Reactions

87. Photosynthesis: Calvin Cycle

88. Factors Affecting the Rate of Photosynthesis Light intensity Carbon dioxide concentration Temperature

89. END