1. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings A Tour of the Cell

2. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lab Notebook Grading 1- Title 3 – Prelab 1 – Purpose 10 - Personal Account: – 1 describe method – 2 hypothesis – 3 table – 3 graph – 1 equation 3 – Discussion 2 – Conclusion

3. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Associated Organelles/Structures to Functions Cell division – nucleus, chromosomes, centrosomes, microtubules, microfilaments Information storage and transferal – nucleus, chromosomes, DNA, RNA, ribosomes, enzymes Energy conversions – mitochondria Manufacture of membranes and products – ribosomes, rough & smooth ER, golgi Lipid synthesis, drug detoxification – smooth ER, perioxisomes

4. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Associated Organelles/Structures to Functions Digestion, recycling – lysosomes, food vacuoles Conversion of H 2 O 2 – peroxisomes Structural integrity – cytoskeleton: microtubules, microfilaments, intermediate filaments, extra cellular matrix Movement – cilia and flagella (microtubules) microfilaments (actin) in muscles & pseudopodia Exchange with environment – plasma membrane, vesicles Cell to cell connections – desmosomes, tight and gap junctions, ECM

5. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plant Cells – Structures and Functions Cell wall – structural support, middle lamella glues cells together Central vacuole – storage, waste disposal, protection, growth Chloroplast – photosynthesis, production of carbohydrates Amyloplast – starch storage Plasmodesmata – cytoplasmic connections b/t cells

6. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Secretory product development and export DNA in nucleus mRNA transcription Ribosomes in cytosol Rough ER modification polypeptide Transport vesicles Golgi apparatus cis face - modify polypeptide Golgi trans face to transport vesicles Fuse to plasma membrane

7. LE 6-16-3 Nuclear envelope Nucleus Rough ER Smooth ER Transport vesicle cis Golgi trans Golgi Plasma membrane

8. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Comparing Prokaryotic and Eukaryotic Cells Basic features of all cells: – Plasma membrane – Semifluid substance called the cytosol – Chromosomes (carry genes) – Ribosomes (make proteins)

9. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Prokaryotic cells have no nucleus DNA is in an unbound region called the nucleoid lack membrane-bound organelles Cellular respiration/photosynthesis takes place underneath the plasma membrane

10. LE 6-6 A typical rod-shaped bacterium A thin section through the bacterium Bacillus coagulans (TEM) 0.5 µm Pili Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella Bacterial chromosome

11. Viewing Cell Components Homogenization Homogenate Tissue cells Differential centrifugation

12. Pellet rich in nuclei and cellular debris Pellet rich in mitochondria (and chloro- plasts if cells are from a plant) Pellet rich in “microsomes” (pieces of plasma membranes and cells’ internal membranes) Pellet rich in ribosomes 150,000 g 3 hr 80,000 g 60 min 20,000 g 20 min 1000 g (1000 times the force of gravity) 10 min Supernatant poured into next tube

13. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Isolating Organelles by Cell Fractionation takes cells apart and separates the major organelles from one another Ultracentrifuges Used to determine the functions of organelles

14. Typical Animal Cell Flagellum Centrosome CYTOSKELETON Microfilaments Intermediate filaments Microtubules Peroxisome Microvilli ENDOPLASMIC RETICULUM (ER Rough ER Smooth ER Mitochondrion Lysosome Golgi apparatus Ribosomes: Plasma membrane Nuclear envelope NUCLEUS In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm) Nucleolus Chromatin

15. Typical Plant Cell Rough endoplasmic reticulum In plant cells but not animal cells: Chloroplasts Central vacuole and tonoplast Cell wall Plasmodesmata Smooth endoplasmic reticulum Ribosomes (small brown dots) Central vacuole Microfilaments Intermediate filaments Microtubules CYTOSKELETON Chloroplast Plasmodesmata Wall of adjacent cell Cell wall Nuclear envelope Nucleolus Chromatin NUCLEUS Centrosome Golgi apparatus Mitochondrion Peroxisome Plasma membrane

16. LE 6-29a EXTRACELLULAR FLUID Proteoglycan complex Collagen fiber Fibronectin Integrin Micro- filaments CYTOPLASM Plasma membrane

17. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Endomembrane System -regulates protein traffic and performs metabolic functions in the cell Components of the endomembrane system: – Nuclear envelope – Endoplasmic reticulum – Golgi apparatus – Lysosomes – Vacuoles – Plasma membrane These components are either continuous or connected via transfer vesicles

18. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Endoplasmic Reticulum: Biosynthetic Factory more than half of the total membrane continuous w/nuclear envelope 2 regions: – Smooth ER, lacks ribosomes – Rough ER, ribosomes studding surface

19. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Smooth ER – Synthesizes lipids – Metabolizes carbohydrates – Stores calcium – Detoxifies poison

20. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Functions of Rough ER – Has bound ribosomes – Produces proteins/membranes, distributed by transport vesicles – a membrane factory

21. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings flattened membranous sacs called cisternae Functions: – Modifies proteins of the ER – Manufactures certain macromolecules – Modifies, sorts and packages materials into transport vesicles – Ex. Modifies glycoproteins and alters phospholipids for membranes Golgi Apparatus: Shipping and Receiving Center

22. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Lysosomes: Digestive Compartments sac of hydrolytic enzymes hydrolyze proteins, fats, polysaccharides, and nucleic acids recycle organelles/macromolecules - autophagy Animation: Lysosome Formation Animation: Lysosome Formation

23. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Ribosomes: Protein Factories in the Cell made of ribosomal RNA & protein carry out protein synthesis: – cytosol (free ribosomes) – on ER or nuclear envelope

24. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Mitochondria and chloroplasts -change energy from one form to another Mito. - cellular respiration Chloro. - only in plants and algae - photosynthesis not part of the endomembrane system

25. LE 6-17 Mitochondrion Intermembrane space Outer membrane Inner membrane Cristae Matrix 100 nm Mitochondrial DNA Free ribosomes in the mitochondrial matrix Mitochondria

26. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Chloroplast DNA Ribosomes Stroma Inner and outer membranes Granum Thylakoid 1 µm Chloroplasts: Capture of Light Energy A plastid chlorophyll & enzymes leaves & green organs of plants/algae structure: – Thylakoids, membranous sacs – Stroma, the internal fluid

27. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Peroxisomes: Oxidation Contain enzymes Break fatty acids down or convert to sugars Detoxify alcohol Produce H 2 O 2 then breaks into water

28. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Vesicle Receptor for motor protein Microtubule of cytoskeleton Motor protein (ATP powered) ATP Roles of the Cytoskeleton: Support, Motility, and Regulation supports cell, maintains shape interacts with motor proteins to produce motility vesicles travel along “monorails” provided by the cytoskeleton

29. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

32. Centrosomes and Centrioles microtubules grow out from a centrosome near the nucleus a “microtubule-organizing center” animal cells- a pair of centrioles

33. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cilia and Flagella Microtubules control the beating of cilia and flagella Video: Chlamydomonas Video: Chlamydomonas Video: Paramecium Cilia Video: Paramecium Cilia Direction of swimming Motion of flagella

34. LE 6-24 0.5 µm Microtubules Plasma membrane Basal body Plasma membrane 0.1 µm Cross section of basal body Triplet Outer microtubule doublet 0.1 µm Dynein arms Central microtubule Cross-linking proteins inside outer doublets Radial spoke

35. LE 6-25a Dynein “walking” Microtubule doublets ATP Dynein arm

36. LE 6-25b Wavelike motion Cross-linking proteins inside outer doublets ATP Anchorage in cell Effect of cross-linking proteins

37. LE 6-26 Microfilaments (actin filaments) Microvillus Plasma membrane Intermediate filaments 0.25 µm

38. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Microfilaments that function in cellular motility contain the protein myosin in addition to actin In muscle cells, thousands of actin filaments are arranged parallel to one another Thicker filaments composed of myosin interdigitate with the thinner actin fibers Video: Cytoplasmic Streaming Video: Cytoplasmic Streaming

39. LE 6-27a Muscle cell Actin filament Myosin filament Myosin arm Myosin motors in muscle cell contraction

40. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cytoplasmic streaming is a circular flow of cytoplasm within cells This streaming speeds distribution of materials within the cell In plant cells, actin-myosin interactions and sol-gel transformations drive cytoplasmic streaming

41. LE 6-27c Nonmoving cytoplasm (gel) Cytoplasmic streaming in plant cells Chloroplast Streaming cytoplasm (sol) Cell wall Parallel actin filaments Vacuole

42. LE 6-28 Central vacuole of cell Plasma membrane Secondary cell wall Primary cell wall Middle lamella 1 µm Central vacuole of cell Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata

43. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings The Extracellular Matrix (ECM) of Animal Cells Animal cells lack cell walls but are covered by an elaborate extracellular matrix (ECM) The ECM is made up of glycoproteins and other macromolecules Functions of the ECM: – Support – Adhesion – Movement – Regulation

44. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Intercellular Junctions Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact Intercellular junctions facilitate this contact

45. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Plants: Plasmodesmata Plasmodesmata are channels that perforate plant cell walls Through plasmodesmata, water and small solutes (and sometimes proteins and RNA) can pass from cell to cell

46. LE 6-30 Interior of cell Interior of cell 0.5 µm PlasmodesmataPlasma membranes Cell walls

47. Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animals: Tight Junctions, Desmosomes, and Gap Junctions At tight junctions, membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid Desmosomes (anchoring junctions) fasten cells together into strong sheets Gap junctions (communicating junctions) provide cytoplasmic channels between adjacent cells Animation: Tight Junctions Animation: Tight Junctions Animation: Desmosomes Animation: Desmosomes Animation: Gap Junctions Animation: Gap Junctions

48. LE 6-31 Tight junctions prevent fluid from moving across a layer of cells Tight junction 0.5 µm 1 µm 0.1 µm Gap junction Extracellular matrix Space between cells Plasma membranes of adjacent cells Intermediate filaments Tight junction Desmosome Gap junctions