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Tour of the Cell and the Central Dogma

This informative article provides a tour of the cell and explores the central dogma of molecular biology. It covers prokaryote and bacteria cells, different types of cells, and the role of organelles such as Golgi, mitochondria, and ER.

markcardenas
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Tour of the Cell and the Central Dogma

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  1. Tour of the Cell and the Central Dogma

  2. Prokaryotebacteria cells Types of cells - no organelles - organelles Eukaryoteanimal cells Eukaryoteplant cells

  3. Golgi mitochondria chloroplast ER Why organelles? • Specialized structures • specialized functions • cilia or flagella for locomotion • Containers • partition cell into compartments • create different local environments • separate pH, or concentration of materials • distinct & incompatible functions • lysosome & its digestive enzymes • Membranes as sites for chemical reactions • unique combinations of lipids & proteins • embedded enzymes & reaction centers • chloroplasts & mitochondria

  4. Cells gotta work to live! • What jobs do cells have to do? • make proteins • proteins control everycell function • make energy • for daily life • for growth • make more cells • growth • repair • renewal

  5. Building Proteins

  6. Proteins do all the work! proteins cells DNA organism

  7. Cells functions • Building proteins • read DNA instructions • build proteins • process proteins • folding • modifying • removing amino acids • adding other molecules • e.g, making glycoproteinsfor cell membrane • address & transport proteins

  8. The Protein Assembly Line Golgiapparatus ribosome ER Building Proteins • Organelles involved • nucleus • ribosomes • endoplasmic reticulum (ER) • Golgi apparatus • vesicles nucleus vesicles

  9. DNA chromosome histone protein nuclear pores nuclear pore nucleolus nuclear envelope Nucleus • Function • protects DNA • Structure • nuclear envelope • double membrane • membrane fused in spots to create pores • allows large macromolecules to pass through

  10. nuclear membrane DNA mRNA Nucleus small ribosomal subunit nuclear pore mRNA large ribosomal subunit cytoplasm 1 production of mRNA from DNA in nucleus 2 mRNA travels from nucleus to ribosome in cytoplasm through nuclear pore

  11. large subunit small subunit ribosome Nucleolus • Function • ribosome production • build ribosome subunits from rRNA & proteins • exit through nuclear pores to cytoplasm & combine to form functional ribosomes rRNA & proteins nucleolus

  12. large subunit small subunit 0.08mm Ribosomes Rough ER Smooth ER Ribosomes • Function • protein production • Structure • rRNA & protein • 2 subunits combine

  13. Types of Ribosomes • Freeribosomes • suspended in cytosol • synthesize proteins that function in cytosol • Bound ribosomes • attached to endoplasmic reticulum • synthesize proteins for export or for membranes membrane proteins

  14. Endoplasmic Reticulum • Function • processes proteins • manufactures membranes • synthesis & hydrolysis of many compounds • Structure • membrane connected to nuclear envelope & extends throughout cell

  15. Types of ER rough smooth

  16. Smooth ER function • Membrane production • Many metabolic processes • synthesis • synthesize lipids • oils, phospholipids, steroids & sex hormones • hydrolysis • hydrolyze glycogen into glucose • in liver • detoxify drugs & poisons • in liver • ex. alcohol & barbiturates

  17. Membrane Factory • Build new membrane • synthesize phospholipids • builds membranes • ER membrane expands • bud off & transfer to other parts of cell that need membranes

  18. Rough ER function • Produce proteins for export out of cell • protein secreting cells • packaged into transport vesicles for export

  19. cisternal space polypeptide signal sequence ribosome membrane of endoplasmic reticulum mRNA cytoplasm Synthesizing proteins ribosome

  20. secretory vesicles transport vesicles Golgi Apparatus • Function • finishes, sorts, tags & ships cell products • like “UPS shipping department” • ships products in vesicles • membrane sacs • “UPS trucks” Which cellshave lots of Golgi?

  21. Golgi Apparatus

  22. protein vesicle budding from rough ER migrating transport vesicle fusion of vesicle with Golgi apparatus ribosome Vesicle transport

  23. TO: TO: TO: endoplasmicreticulum nucleus proteinon its way! DNA RNA vesicle vesicle ribosomes TO: protein finishedprotein Golgi apparatus Making Proteins

  24. nucleus cell membrane nuclear pore protein secreted rough ER vesicle ribosome proteins smooth ER transport vesicle Golgi apparatus cytoplasm Putting it together… Making proteins

  25. Storage of water or ions, pigments, hold food, pump out water. Are larger than vesicles formed from golgi/E.R. In plants is enclosed by Tonoplast (membrane) and provides cell with hydrostatic pressure Vacuoles

  26. Peroxisomes • Contain enzymes (catalase) that break down H2O2 formed during metabolism of alcohols, F.A.’s. • Specialized forms [glyoxysome] found in seeds and function during germination.

  27. Cytoskeleton • Protein fibers that support and give shape to a cell, involved in organelle movement throughout cell, chromosome movement during cell division and large cell movements (cell motility and cytokinesis) • 3 Groups of Fibers classified according to size: • Mircrotubules (thickest) • Intermediated filaments (middle sized) • Microfilaments (thinnest)

  28. Components of the Cytoskeleton • Microtubules • hollow tube. • Provide framework for cell, organized by centrosome from which they usually originate. • “Rail” system for organelle transport. • Component of Centriole. • Replicated prior to mitosis. • Form Cilia and Flagella. • 9 + 2 arrangement (eukaryotic characteristic)

  29. Components of the Cytoskeleton • Microfilaments (aka actin filaments) • Solid “rope”of two actin proteins • Thinner and more flexible than microtubules • Principle component of muscle fibers. • Provide mechanism to support cell shape. Found just inside the c. mem. • Enable cell movement, phagocytosis and cytokinesis.

  30. Cell-to Cell Junctions • Plants • Plasmodesmata • Perforations in cell wall that allow passage for water/solutes to adjacent cells. • Animals • Tight Junctions. Prevent leakage between cells (ie. Stomach) • Desmosomes. Mechanically attach cells to each other. Serve as anchoring sites for inter. filaments in cell. • Gap Junctions. Analogous to plasmodesma. Fxn as comm. Pathway between cells. Cardiac muscle, nerves.

  31. Intracellular Junctions

  32. Plant Cell Walls • Protect plants, allow for shape and prevent excess H2O uptake. • Composed of cellulose • Plasmodesmata connect neighboring cells.

  33. Extracellular matrix (ECM) • Intricate network of proteins and polysaccharides that are organized into a meshwork on the outside of cells. • Large polysaccharides and proteoglygans form a “gel-like” material that resist compression. • Proteins like collagen (most abundant protein in animals as part of bone and skin) and elastin(stretch and recoil) provide structure and strength. • Adhesive-like proteins (fibronectins and laminin) help cells attach to the appropriate part of the ECM.

  34. Extracellular matrix (ECM)

  35. Any Questions!!

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