Cell Structures & Function (Ch. 4)

1. Cell Structures & Function (Ch. 4) Joke: 2 H in a bar… Microscopic view of cell stained to show several types of molecules

2. Cell structures and functions Animal Cell

3. Cell structures and functions 2. cytoplasm 3. nucleus 1. plasma membrane Animal Cell

4. Cell structures and functions 4) Mitochondrion Animal Cell

5. Cell structures and functions • 4) Mitochondrion: Generates “spendable” energy (ATP). Outer membrane + folded inner (forms “cristae”)

6. Cell structures and functions 6) Ribosomes (dots) 5) Endoplasmic reticulum Animal Cell 7) Golgi apparatus

7. Cell structures and functions • 5) Endoplasmic reticulum (ER): Membrane sacs & channels transport materials (“freeway system”). • 6) Ribosomes: Granules used in making proteins (“protein factories”)

8. ER • Rough ER: has ribosomes (making proteins) • Smooth ER: no ribosomes. Make lipids & others. • Liver: enzymes on smooth ER “Detox centers” (break down drugs)

9. Golgi apparatus • 7) Golgi apparatus: Sorting, processing, shipping center

10. Golgi apparatus • 7) Golgi apparatus: Sorting, processing, shipping center

11. Cell structures and functions 8) Lysosome Animal Cell

12. Lysosomes • Lysosome: bag digestive enzymes • “lyso-”=split • “-some”=body • “Recycling centers” (digest food)

13. Lysosome storage diseases • Pompe’s disease: glycogen not broken down by liver • Tay-Sachs disease: lipids not broken down (damages nerve cells in brain)

14. Cell structures and functions Clusters protein tubules Function: cell division (covered later….) 9) Centrioles Animal Cell

15. Cell structures and functions 10) Flagellum

16. Flagellum: propeller • Moves cell through liquid • Humans: Only on sperm cells Sperm cells on ovum

17. Other propellers: cilia • Cilia plural (singular: cilium) • Hairlike projections: move back & forth • Humans: lung passages, move mucus to throat • Smoking paralyzes!

18. Other propellers: cilia • Some unicellular organisms: swim • Ex: Paramecium

19. PLANT CELL Golgi body central vacuole vesicle rough ER) microfilaments (components of cytoskeleton) ribosomes (attached to rough ER) ribosomes in cytoplasm smooth ER mitochondrion DNA + nucleoplasm chloroplast nucleolus NUCLEUS nuclear envelope plasma membrane microtubules (components of cytoplasm) cell wall

20. central vacuole chloroplast cell wall

21. More cell structures: plant cells • Cell wall: Cellulose, outside plasma membrane. • Cell shape & strength

22. Chloroplast: Does photosynthesis (captures sun energy into sugar molecules) Note grana (stacks of sacs) and stroma (fluid matrix) Chloroplast

23. Vacuoles • Large membrane “bags” • Most plant cells: huge “central vacuole” (storage) Plant cell TEM micrograph Centralvacuole Cell walls Nucleus

24. Nucleus Contractilevacuoles Other Vacuoles • Some unicellular organisms: “contractile vacuoles” (expel water)

25. Cytoskeleton • Protein tubes: Cell shape, hold organelles • Some cells: “ameboid movement” • Change cytoskeleton (change cell shape) • Projections: “pseudopods” Direction movement Amoeba movie Pseudopods

26. Human cells: white blood cells Bacteria cells Pseudopods

27. Movement in cells of aquatic plant: Elodea • Called cyclosis (Lab #3)

28. Multicellular life: joining cells • Cell junctions: transport materials + cell-to-cell communication • Plant cells: plasmodesmata (holes in walls between adjacent cells) • Animal cells: several types junctions

29. Life’s groups and their cells • 3 main domains of life • Archaea • Bacteria • Eukarya

30. Archaea and Bacteria cells • Most unicellular • Very small, simple (1/10 size other cells)

31. Archaea and Bacteria cells • Mostly unicellular • Cells very small, simple (1/10 size other cells) • Prokaryotes: Cell wall, plasma membrane, ribosomes, DNA. If flagella, differ from other flagella. • NO nucleus, mitochondria, chloroplasts, ER

32. Prokaryotic cell DNA plasma membrane bacterial flagellum capsule ribosomes in cytoplasm pilus cell wall cytoplasm

33. Prokaryote example TEM micrograph • Bacterial cell (rod-shaped) Bacillus infernus: The “bacillus from Hell” From rock 3 km deep!

34. Prokaryote example (lab #3) • Cyanobacterium called Anabaena • Photosynthetic prokaryote

35. Eukaryote cells • Larger/more complex than prokaryotes • Nucleus • Other organelles • Mitochondria • ER

36. Eukaryote groups • Protists • Fungi • Plants • Animals

37. Protists • 2 main groups • 1) Algae: photosynthetic protists (chloroplasts) • 2) Protozoans: eat other organisms • Ex: Paramecium, Amoeba Volvox Giant kelp

38. Fungi • Have: cell walls, nuclei, mitochondria, ribosomes • No chloroplasts, usually no flagella • Molds, yeasts, mushrooms

39. Plants • Have: cell walls, chloroplasts, central vacuole • Also nuclei, ER, mitochondria, ribosomes, golgi apparatus • Most lack flagella/cilia, centrioles Federally endangered AL plants!

40. Animals • No cell walls, chloroplasts, central vacuoles • Have: lysosomes, centrioles, flagella, etc.

41. Ch. 5: Membranes • Flying fox (bat) mother and baby

42. Membranes • Membranes: important surfaces • Organize contents, provide surfaces in which molecules embedded, etc. Plasma membrane is between arrows

43. Flashback: Cell structures • Most involved membranes.

44. Structure of membranes • Basic unit: phospholipid molecule • Two fatty acids • Glycerol • Phosphate group.

45. Structure of membranes • Head hydrophilic: attracted to water • Tails hydrophobic: repelled by water • What happens when phospholipids in water?

46. Structure of membranes

47. Structure of membranes • Two layers • Phospholipid bilayer (“bi-” = 2).

48. Structure of Membranes • Other molecules • Cholesterol (sterol, type lipid): makes membranes flexible

49. Roles of membrane proteins (5) • Proteins: many tasks • 1) Attachment points: cytoskeleton and fibers outside cell (hold cells together). Animal cell membrane

50. Roles of membrane proteins • 2) Recognition proteins • Cell belongs to organism • Type cell (other cells recognize function)