1. Cell Structure and Function Chapter 3

2. The Cell--Considerations Basic unit of life Protection and support Movement Communication Metabolism and energy release Inheritance

3. Cell Theory All living things are made up of cell(s) Cells are smallest living unit of structure and function for all organisms All cells arise from preexisting cells (No spontaneous generation)

4. Why Are Cell So Small?

5. Sizes of living things

6. Prokaryotes vs Eukaryotes Prokaryotes –“Before nucleus” –DNA in nucleoid region –Ribosomes –Cell membrane –No membrane–bound organelles Eukaryotes –“True nucleus” –DNA in double membrane bound nucleus –Ribosomes –Cell membrane –Membrane –bound organelles

7. Typical Bacterium---A Prokaryote

8. Typical Animal Cell-A Eukaryote

9. Plasma Membrane

10. Animal cell anatomy

11. Plant cell anatomy

12. Nucleus--The Brains of the Cell

13. Nucleus DNA dispersed throughout Consists of : –Nuclear envelope: Separates nucleus from cytoplasm and regulates movement of materials in and out –Chromatin: Condenses to form chromosomes during cell division –Nucleolus: Assembly site of large and small ribosomal units

14. Ribosomes Sites of protein synthesis Composed of a large and small subunit Types –Free –Attached to endoplasmic reticulum

15. Composition of eukaryotic and prokaryotic ribosomes

16. Cryoelectron microscopy–based image of the E. coli ribosome at ~25 Å resolution. Mol. Biol. Gene, Fig. 14-21

17. The Endomembrane System Nuclear envelope Endoplasmic reticulum Golgi apparatus Vesicles

18. Endoplasmic Reticulum Types –Rough Attached ribosomes Proteins produced and modified –Smooth No attached ribosomes Manufacture lipids Cisternae or Lumen: Interior spaces isolated from rest of cytoplasm

19. Golgi Apparatus—Traffic Cop Modification, packaging, distribution of proteins and lipids for secretion or internal use Flattened membrane sacs stacked on each other

20. Function of Golgi Apparatus

21. Action of Lysosomes

22. Peroxisomes and Proteasomes Peroxisomes –Smaller than lysosomes –Contain enzymes to break down fatty and amino acids –Hydrogen peroxide is a by-product of breakdown Proteasomes –Consist of large protein complexes –Include several enzymes that break down and recycle proteins in cell

23. Energy Management Organelles Mitochondria –Aerobic Respiration Chloroplasts –Photosynthesis

24. Circle of Life Carbon compounds, O 2 CO 2, H 2 O Respiration Photosynthesis Energy Mitochondria Chloroplasts Complex>>Simple

25. Mitochondria—Powerhouse of the Cell In all eukaryotes Major site of ATP synthesis Membranes –Outer –Cristae: Infoldings of inner membrane Matrix: Substance located in space formed by inner membrane

26. Chloroplast

27. Animal cell anatomy

28. Plant cell anatomy

29. The Cytoskeleton Function: –Maintenance of cells shape –Movement within cytoplasm –Cell movement –Intracellular communication? Three components –Actin filaments –Microtubules –Intermediate filaments

30. FUNCTION: CYTOSKELETON= complex network of filamentous proteins extending throughout the cytoplasm Three types of filaments: Microtubules Microfilaments Intermediate Filaments Cell shape Motility: crawling, chemokinesis chemotaxis endo- and exo-cytosis) Anchoring of organelles and cellular structures Organelle movement Cell polarity Tensile strength Chromosome movement

31. helical structure, diameter ~ 7 nm EX. intestinal microvilli ACTIN FILAMENTS

32. MICROFILAMENTS ACTIN STRUCTURES IN CELLS: MICROVILLI STRESS FIBRES FOCAL ADHESIONS LAMELLIPODIA FILOPODIA (or MICROSPIKES CONTRACTILE RING (cell division)

33. hollow cyllinders, diameter ~ 25 nm, emanating from the MTOC

34. Microtubule structure Made of  and β Tubulin

35. rope-like fibres, diameter ~ 10 nm, nuclear, cytoplasmic, connecting cell-cell junctions

36. Structure of intermediate filaments

37. micro- tubules micro- filaments intermediate filaments Cytoskeleton Elements

38. Centrioles

39. In specialized zone near nucleus: Centrosome Each unit consists of microtubules Before cell division, centrioles divide, move to ends of cell and become spindle fibers

40. Cilia and flagella Cilia (small and numerous) and flagella (large and single) –9 + 2 pattern of microtubules – Iinvolved in cell movement. –Each has a basal body at its base. Plant cells lack centrioles

41. Structure of a flagellum or cilium

42. Prokaryotes vs Eukaryotes Prokaryotes –“Before nucleus” –DNA in nucleoid region –Ribosomes –Cell membrane –No membrane–bound organelles Eukaryotes –“True nucleus” –DNA in double membrane bound nucleus –Ribosomes –Cell membrane –Membrane –bound organelles

43. Evolution of the eukaryotic cell- Endosymbiotic Hypothesis

44. SUMMARY Cell Theory Physics of Cell Size Eukaryotes –Nucleus –Membrane Bound Organelles ER Golgi Vesicles, ex. Lysosomes –Energy Management Organelles –Cytoskeleton –Prokaryotes –Endosymbiosis