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Cell Theory

Cell Theory. The cell is the smallest structural and _ Organismal functions depend on ____________________________________ cell functions Biochemical activities of cells are dictated by their specific subcellular structures ___________________________________ of life has a cellular basis.

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Cell Theory

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  1. Cell Theory • The cell is the smallest structural and _ • Organismal functions depend on ____________________________________ cell functions • Biochemical activities of cells are dictated by their specific subcellular structures • ___________________________________ of life has a cellular basis

  2. Cell Diversity • Over _ • Types differ in size, shape, subcellular components, and functions

  3. Generalized Cell • All cells have some common structures and functions • Human cells have three basic parts: • Plasma membrane • flexible outer boundary • Cytoplasm • intracellular fluid containing organelles • Nucleus • control center

  4. Plasma Membrane • Bimolecular layer of lipids and proteins in a constantly changing _ • Plays a _ • Separates intracellular fluid (ICF) from extracellular fluid (ECF)

  5. Membrane Proteins • Firmly inserted into the membrane (most are transmembrane) • Functions: • Transport proteins (channels and carriers), enzymes, or _

  6. Membrane Proteins • Loosely attached to integral proteins • Include ________________________on intracellular surface and glycoproteins on extracellular surface • Functions: • ________________________________, motor proteins, cell-to-cell links, provide support on intracellular surface, and form part of glycocalyx

  7. Functions of Membrane Proteins • ________________________________ for signal transduction • Attachment to cytoskeleton and extracellular matrix

  8. Functions of Membrane Proteins

  9. Membrane Junctions • Three types:

  10. Membrane Junctions: Tight Junctions

  11. Membrane Junctions: Desmosomes

  12. Membrane Junctions: Gap Junctions • Transmembrane proteins form _ • For spread of ions between cardiac or smooth muscle cells

  13. Membrane Transport • Plasma membranes are _ • Some molecules easily pass through the membrane; others do not

  14. Types of Membrane Transport • Substance moves down its concentration gradient • Occurs only in living cell membranes

  15. Passive Processes • Carrier-mediated facilitated diffusion • Channel-mediated facilitated diffusion

  16. Passive Processes: Simple Diffusion • Nonpolar lipid-soluble (hydrophobic) substances _

  17. Passive Processes: Facilitated Diffusion • Certain lipophobic molecules (e.g., glucose, amino acids, and ions) use _________________________________, both of which: • Exhibit _ • Are ________________________________; rate is determined by number of carriers or channels • Can be regulated in terms of activity and quantity

  18. Facilitated Diffusion Using Carrier Proteins • Transmembrane integral proteins transport specific polar molecules (e.g., sugars and amino acids)

  19. Facilitated Diffusion Using Channel Proteins • Aqueous channels formed by transmembrane proteins selectively transport ions or water • Two types: • Leakage channels • Gated channels

  20. Passive Processes: Osmosis • Movement of _ • Water diffuses through plasma membranes: • Through the lipid bilayer

  21. Passive Processes: Osmosis • Water concentration is determined by solute concentration because _ • When solutions of different osmolarity are separated by a membrane, _

  22. Tonicity • Tonicity: The ability of a solution to cause a cell to shrink or swell • A solution with the same solute concentration as that of the cytosol • A solution having greater solute concentration than that of the cytosol • A solution having lesser solute concentration than that of the cytosol

  23. Membrane Transport: Active Processes • Two types of active processes: • Both use _____________________ to move solutes across a living plasma membrane

  24. Active Transport • Requires _ • Moves solutes _____________________ a concentration gradient

  25. Vesicular Transport • Transport of _______________________, macromolecules, and fluids across plasma membranes • Requires cellular energy (e.g., ATP)

  26. Vesicular Transport • Functions: • Exocytosis • Endocytosis • transport into cell • Transcytosis • Substance (vesicular) trafficking • transport from one area or organelle in cell to another

  27. Endocytosis and Transcytosis • Involve formation of protein-coated vesicles • Often _

  28. Endocytosis • Phagocytosis _ • pseudopods engulf solids and bring them into cell’s interior • Pinocytosis _ • plasma membrane in-folds, bringing ______________________________________ and solutes into interior of the cell

  29. Exocytosis • Examples: • Neurotransmitter release • Ejection of wastes

  30. Cytoplasm • material between plasma membrane and the nucleus • largely water with dissolved protein, salts, sugars, and other solutes

  31. Cytoplasm • metabolic machinery of the cell • chemical substances such as glycosomes, glycogen granules, and pigment

  32. Cytoplasmic Organelles • Specialized cellular compartments • Mitochondria, peroxisomes, lysosomes, endoplasmic reticulum, and Golgi apparatus • Cytoskeleton, centrioles, and ribosomes

  33. Mitochondria • Double membrane structure with shelf-like cristae

  34. Ribosomes • Granules containing protein and _ • Site of _ • Free ribosomes synthesize _ • Membrane-bound ribosomes synthesize proteins to be _

  35. Endoplasmic Reticulum (ER) • Interconnected tubes and parallel membranes enclosing cisternae • Continuous with the _ • Two varieties

  36. Rough (ER) • External surface studded with ribosomes • Manufactures _ • Responsible for the synthesis of _

  37. Smooth ER • Tubules arranged in a looping network • Catalyzes the following reactions in various organs of the body • In the liver • breakdown _ • detoxification of drugs • In the testes • synthesis of steroid-based hormones: _

  38. Golgi Apparatus • Stacked and flattened membranous sacs • Functions in • Concentration • Transport vessels from the ER fuse with the cis face of the Golgi apparatus

  39. Golgi Apparatus • Proteins then pass through the Golgi apparatus to the _ • Secretory vesicles leave the trans face of the Golgi stack and move to designated parts of the cell

  40. Lysosomes • Spherical membranous bags _ • Digest ingested bacteria, viruses, and toxins • Degrade _ • Breakdown nonuseful tissue • Breakdown _ • Secretory lysosomes are found in _

  41. Peroxisomes • Membranous sacs containing _ • _______________________________ harmful or toxic substances • Neutralize dangerous free radicals • Free radicals – highly reactive chemicals with unpaired electrons (i.e., O2–)

  42. Cytoskeleton • The “skeleton” of the cell • ______________________________, elaborate series of rods running through the cytosol • Consists of _

  43. Centrioles • Small barrel-shaped organelles located in the centrosome near the nucleus • Pinwheel array of nine triplets of microtubules • Form the bases _

  44. Cilia • Whip-like, motile cellular extensions _

  45. Nucleus • Contains _ • Gene-containing control center of the cell • Contains the genetic library with blueprints for nearly all cellular proteins • Dictates the _

  46. Nuclear Envelope • _______________________________ double membrane barrier containing pores • Encloses jellylike _

  47. Nuclear Envelope • Outer membrane is ______________________________________ and is studded with ribosomes • Inner membrane is lined with the nuclear lamina, • which _ • ______________________________________ regulates transport of large molecules into and out of the nucleus

  48. Nucleoli • Dark-staining _ • Site of _

  49. Chromatin • Threadlike strands of _ • Form condensed, barlike bodies of _

  50. Cell Cycle • Growth (G1), synthesis (S), growth (G2) • Mitosis and cytokinesis

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