1. Unit 4: Cell Biology and Energy Processes

2. The history… A long time ago, before microscopes were invented, people had no idea what caused sickness.

3. Superstition… They thought that illness was caused by curses and supernatural spirits.

4. Leeuwenhoek and Hooke In the 1600’s Leeuwenhoek observed microorganisms in water. At the same time Hooke was observing cork samples under a microscope.

5. What is a microscope? It is an instrument used to observe small objects. There are two main kinds: compound light microscope electron microscope

6. Light microscopes… use a series of lenses to magnify objects. Maximum magnification= no more than 1500X. It produces images like the one you see on your right of a microorganism.

7. Electron microscopes… were developed in the 1930’s and use a beam of electrons rather than light. Maximum magnification: 500,000X. It produces images like the one on the right.

8. Cell Theory 1.All organisms are composed of one or more cells. 2.The cell is the basic unit of structure and organization of organisms. 3.All cells come from preexisting cells.

9. Two Basic Cell Types Prokaryotic cells do not have membrane-bound organelles (e.g.: Nucleus). Eukaryotic cells contain membrane-bound organelles.

11. Orga-who? Organelles are small specialized structures found in cells. Bodies have organs; cells have organelles.

12. Cell Wall The cell wall is a fairly rigid structure located outside the plasma membrane that provides additional support and protection.

13. Nucleus The central membrane-bound organelle that manages or controls cellular functions Contains DNA

14. Nucleolus prominent organelle found in nucleus which produces ribosomes.

15. Ribosomes produce proteins

16. Cytoplasm a clear, gelatinous fluid inside the cell.

17. Endoplasmic Reticulum “inter-cellular highway” facilitates creation & transportation of proteins Rough ER has ribosomes. Smooth ER does not.

18. Additional Functions The smooth ER produces lipids and steroids It also regulates calcium levels and is important for drug detoxification Liver cells tend to be rich in smooth ER

19. Golgi Apparatus is a flattened stack of tubular membranes that modifies proteins. It sorts proteins into packages and packs them in membrane- bound structures called vesicles for transportation.

20. Vacuoles are membrane-bound components used for temporary storage of materials. Hold water in plant cells

21. Lysosomes are organelles that contain enzymes and digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. Defend cell from invaders

22. Chloroplasts capture light energy and convert it into chemical energy (photosynthesis). Contain chlorophyll, which makes plants green Only found in plants*

24. Mitochondria are membrane-bound organelles that transform food into energy for the cell. Responsible for aerobic cellular respiration

25. The Cytoskeleton is a recently discovered cell support structure. It is made up of hollow structures called microtubules (above) and microfilaments (below).

26. Centrioles play an important role in cell division.

27. Locomotion of Cells Cilia are hair-like structures used for movement. Flagella are tail-like projections that are used whip-like motions for movement.

28. The Plasma Membrane is the flexible boundary between the cell and its environment. phospholipids have a polar head and a non- polar tail

29. Parts of the Plasma Membrane phospholipids have a glycerol backbone, two fatty acids chains and a phosphate group. The phosphate group is polar

30. Bilipid layer The lipids have a side that likes water (hydrophilic) and a side that hates water (hydrophobic). So it naturally forms a bilayer that keeps its hydrophobic parts hidden from water and its hydrophilic parts touching water.

31. Transport Proteins move needed substances or waste materials through the plasma membrane. This helps to make the membrane selectively permeable. It selects what comes in and goes out

32. Cellular Transport Osmosis is the diffusion of water across a semi- permeable membrane. Always High concentration => low It is a passive process (no energy requirement)

33. Solutions… isotonic = solution in which equal concentration inside and outside of cell. hypotonic = less ions in solution than cell (more water on outside, water floods cell) hypertonic = more ions in solution than cell (less water outside, water comes out and cell shrinks)

34. Solutions Solution Concentration of ions in solution Result IsotonicEqualNormal cell size Hypotonic Less than inside the cell Water floods cell, cell swells and bursts Hypertonic Greater than inside the cell Water leaves cell; cell shrivels and shrinks

36. Passive Transport movement of particles across a membrane that requires no energy. When it uses no energy but does require using a membrane protein it is known as facilitated diffusion.

37. Active Transport is movement across the membrane that requires energy. This happens when molecules are being moved against the gradient.

38. Transport of Large Molecules Endocytosis is a process by which a cell surrounds and takes in material from its environment. Exocytosis is the expulsion or secretion of materials from a cell.

39. Specialized Cells Not all cells in the body are exactly the same Different types of cells will have more of certain organelles in order to perform specialized functions

40. For example… White blood cells have extra lysosomes Liver cells have extra smooth IR There are hundreds of different cell types in the human body

41. Stem Cells Are special cells that can transform into other cells

42. Nerve Cells Are specialized cells that are extremely long and can send electrical signals to and from the brain They are how we can feel things

43. Energy Processes There are three major energy process that we will study in the cell: 1.photosynthesis 2.cellular respiration 3.fermentation

44. Photosynthesis… the process that uses the sun’s energy to produce simple sugars 6CO 2 + 6H 2 O + (light) → C 6 H 12 0 6 + 6O 2 (carbon water energy glucose oxygen dioxide)

46. Actually 2 Processes Photosynthesis is actually 2 different processes: Light dependent reactions require sunlight and water Light independent reactions only require CO 2 and typically take place at night

47. The Dark Cycle Light independent reactions are also known as “the Dark Cycle” They are not evil.

48. Cellular Respiration… is the process by which mitochondria break down glucose molecules to produce ATP. ATP stores energy in the form of chemical bonds Can be aerobic (needs O 2 ) or anaerobic (doesn’t need O 2 ) C 6 H 12 0 6 + 6O 2 → 6CO 2 + 6H 2 O + 36 ATP (energy)

50. Anaerobic respiration (Fermentation) There are two types: lactic acid fermentation alcoholic fermentation

51. Lactic Acid Fermentation Happens in your muscles during exercise Is responsible for the “burn” you get when exercising (acid) Produces small amounts of ATP without O 2

52. Alcoholic Fermentation Yeast and other bacteria do this instead of lactic acid fermentation Produces ethanol (alcohol) instead of lactic acid Also produces CO 2, which is what makes breads rise

53. Aerobic vs. Anaerobic Aerobic Respiration 36-38 molecules of ATP per sugar molecule Requires Oxygen Anaerobic Respiration 2 molecules of ATP per sugar molecule Does not require Oxygen =Aerobic Respiration produces more energy but requires oxygen to function