The document summarizes key properties and structures of cells. It discusses that all living things are made of cells, which are the basic unit of life. It describes the differences between prokaryotic and eukaryotic cells, and some of the major organelles in plant and animal cells like the nucleus, mitochondria, chloroplasts, cell membrane, cytoskeleton etc. It explains their functions and importance for cellular processes.

1. Cells

2. Which of the following is/are properties of life? A) a complex organization B) the ability to take in energy and use it C) the ability to respond to stimuli from the environment D) the ability to reproduce E) All of the choices are correct.

3. A compound A) is a pure element. B) is less common than a pure element. C) contains two or more elements in a fixed ratio. D) is exemplified by sodium. E) is a solution.

4. All living things are made of cells Cells are the basic unit of living things All cells come from other cells This is the classical cell theory

5. Developments in the microscope facilitated development of Cell theory The drawings of Robert Hooke A dramatization of Antony van Leeuwenhoek

6. Microscope power is limited by the wavelength of light used Visible light, 400-700nm in wavelength, is a small part of the electromagnetic spectrum

7. Light is a wave

8. 2 waves can add to each other, or cancel each other out When waves are in phase, they are added together When waves are out of phase, they cancel each other out

9. Advances in microscopy continue to further knowledge of cells Electron microscopy allows far greater magnification than light microscopy Electron wavelengths are far shorter than those of visible light

10. Transmission Electron Microscope Very thin sections are made of a sample A beam of electrons is passed through the sample “ Electron-dense” material in sample appears darker

11. Scanning Electron Microscope A thin film of gold is sprayed onto the surface of a specimen Electrons are reflected off surface Gives images 3-D appearance

12. Phase contrast microscope Speed of light slows down as light passes through a medium Wavelengths out of phase with each other will cancel out and appear darker Allows viewing live specimens without staining

13. Fluorescent microscopy

14. Cells are small Most bacteria are .5-2µm in size Light microscope’s limit= ~500nm=.5µm Single eukaryotic cells are larger, but still to small to see without magnification

15. Cells are small for good reason Surface area: volume ratio Rate of food/oxygen entering the cell depends on surface area For large volumes, this rate would approach zero

16. How do you think nerve and muscle cells manage their size? Turn to your neighbor and discuss this question.

17. Required for all cells: A genome Separation of inside from outside Means of obtaining energy Means of utilizing energy Protection

18. All living things can be placed into three domains Based on DNA evidence, all multicellular life is put into a single group, the eukaryotes Unicellular, prokaryotic life split into Eubacteria & Archaea

19. Cells can be placed into two categories Prokaryotic and eukaryotic Prokaryotic - smaller and simpler Eukaryotic - larger and more complex Eukaryotic- containing membrane-bound organelles Eukaryotes- “you”

20. Prokaryotic cells are smaller and simpler Archaebacteria and Eubacacteria are both prokaryotic Pro= before Karyo= “kernel” (nucleus) The prokaryotic genome is a circular piece of DNA

21. Cell structures common to most prokaryotes Flagellum Ribosomes Pili Cell wall Cell membrane (plasma membrane) Cytoplasm Most structures found in prokaryotes are also found in eukaryotes

22. The Cell Membrane is a flexible envelope for all cells Often made of a phospholipid bilayer All substances entering or exiting cell must pass To be discussed in detail in subsequent chapter

23. The Cell Membrane is a dynamic fluid mosaic Receptor proteins, transport proteins, cholesterol, and the phospholipid bilayer

24. The cell membrane works for: Containment Transport Communication Attachment

25. Ribosomes are the site of protein manufacture DNA blueprint is converted to mRNA At the ribosome, the mRNA is converted into protein Ribosomes are slightly different in eukaryotes, but the function is the same

26. Ribosomes convert RNA instructions into protein

27. Eukaryotic cells contain membrane-bound organelles

28. Eukaryotes can be unicellular or multicellular Protists- mostly unicellular eukaryotes Animals, plants, fungi- mostly multicellular eukaryotes

29. The cells of plants and animals are different

30. The nucleus contains the cell’s DNA

31. The endomembrane system is contiguous with the nuclear membrane Proteins fated for export will be made on rough ER surface ribosome Membrane bound proteins are also sent here Ribosomes are also suspended in cytosol for synthesis of cytosolic proteins

32. The smooth ER plays a role in lipid synthesis and postranslational modification of proteins ER: endoplasmic reticulum Rough ER: with ribosomes on it Translation: turning mRNA  protein Addition of sugars/ lipids to the surface of a protein can aid or change its function

33. The Golgi apparatus does further postranslational modification Other modifications can serve as address labels Also key in the synthesis of lysosomes

34. Lysosomes are vesicles that contain digestive enzymes The pH inside a lysosome is different from the pH of the cytosol Lysosomes can be fused to food

35. LE 4-10a-1 Plasma membrane Rough ER Lysosomes Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus

36. LE 4-10a-2 Plasma membrane Rough ER Lysosomes Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Engulfment of particle “ Food” Food vacuole Digestion

37. LE 4-10a-3 Plasma membrane Rough ER Lysosomes Transport vesicle (containing inactive hydrolytic enzymes) Golgi apparatus Engulfment of particle “ Food” Food vacuole Digestion Lysosome engulfing damaged organelle

38. The nucleoid region of a prokaryotic cell A) contains the cell's DNA. B) separates the RNA from the cytoplasm. C) is surrounded by a nucleoid membrane. D) contains the cell's nucleoli. E) is the site of organelle production.

39. Pulse-chase experiments can demonstrate paths through endomembrane system Add normal cells to a “pulse” medium containing a radioactively labelled nutrient- 14 C - leucine “ Chase” with normal media Take samples of the cells every 10 min or so Cover samples with photographic emulsion and view

40. The mitochondrion breaks down nutrients to provide energy for cells 100’s of mitochondria in a single cell Site of cellular respiration ATP is provided to the cell They can decide a cell’s time to die They have their own DNA Celluar respiration: C 6 H 12 O 6(s) + 6O 2(g)  6CO 2(g) + 6H 2 O (l) + energy

41. Plant cells have some distinctive organelles absent in cells of animals A large central vacuole is common in plants In plants, it is for storage of: water, sugars and acids, toxins, flower pigments, Provides shape

42. Vacuoles are not exclusive to plants

43. Plant cell walls are mostly composed of sugars Section of a pine board 3 nm Polymerized glucose- cellulose

44. Chloroplasts feed the world The organelle capable of performing photosynthesis: 6CO 2(g) + 6H 2 O (l) + h ν  C 6 H 12 O 6(s) + 6O 2(g) They contain chlorophyll , a green pigment which captures light They also contain their own DNA

45. Why do you think chloroplasts and mitochondria have their own DNA? Turn to a neighbor and discuss this question.

46. Why do chloroplasts and mitochondria have their own DNA? Mitochondrial genes are similar to those of α -proteobacteria The endosymbiosis between mitochondria and eukaryotic cells appears to have a single origin In humans, 95% of mitochondrial genes are in the nucleus

47. Scientists are less sure of a single origin for chloroplasts The lineage of plastids has become a field of study unto itself Includes secondary endosymbioses And tertiary ones Chloroplast genomes have widely disparate sizes Chloroplasts also appear to have a single origin

48. The Cytoskeleton Actin microfilaments are contractile Intermediate filaments provide shape Microtubule s help cells divide and provide highways on which vesicles can travel Vesicles- small membrane bound containers

49. Cytoskeleton elements work together in eukaryotic cilia and flagella

50. Motor proteins literally walk on microtubules Kinesin- plus-end directed Dynein- minus-end directed Both can carry vesicles http://video.google.com/videosearch?q=kinesin&hl=en&emb=0#

51. Junctions in plants allow cells to share cytoplasm Can contain nutrients or chemical signals Viral infections also can spread through these junctions

52. Junctions in animal cells can make tissues water-tight Anchors and tight junctions are found in the blood-brain barrier Gap junctions allow cell to cell communication as plasmodesmata in plants

53. A cell is exposed to a substance that prevents it from dividing. The cell becomes larger and larger. This situation A) should present no problem to the cell since it can continue to perform all other necessary functions. B) should present no problem to the cell because the surface area of the cell will increase as the volume of the cell increases. C) will eventually be problematic since the cell's ability to absorb nutrients through its outer membrane will not keep increasing as quickly as its cytoplasmic needs. D) should be beneficial- the cell will be able to divert the ATP normally used for cell division to other processes. E) None of the choices are correct.