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THE CELL

THE CELL. Cellular Organization. Cell Tissue – group of cells functioning together. Organ – group of tissues functioning together. Organ System – group of organs functioning together. Organism – group of organ systems functioning together. Cell Size. 1. 1–100µm

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THE CELL

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  1. THE CELL

  2. Cellular Organization • Cell • Tissue – group of cells functioning together. • Organ – group of tissues functioning together. • Organ System – group of organs functioning together. • Organism – group of organ systems functioning together.

  3. Cell Size 1. 1–100µm 2. Why is there a limit to cell size? a. Surface-to-volume ratio b. Distance from surface to center

  4. CELL SIZE The smaller the object the greater its ratio of surface area to volume. The nucleus can better control a smaller cell

  5. tallest trees adult human chicken egg frog embryo most eukaryotic cells mitochondrion most bacteria virus proteins diameter of DNA double helix atoms

  6. nucleus nuclear pores

  7. CELL THEORY All organisms are made up of cells All substances in organisms are products of cells Cells come from other cells by reproduction

  8. Microscopes and Cells • 1830’s. • Mathias Schleiden identified the first plant cells and concluded that all plants made of cells. • - Thomas Schwann made the same conclusion about animal cells.

  9. Microscopes and Cells • Robert Hooke used the first compound microscope to view thinly sliced cork cells. • Compound scopes use a series of lenses to magnify in steps. • Hooke was the first to use the term “cell”.

  10. Microscopes and Cells • 1600’s. • Anton van Leeuwenhoek first described living cells as seen through a simplemicroscope.

  11. The History of the Cell • The Cell • The basic unit of an organism • Discovery made possible by the invention of the microscope

  12. Two Basic Cell Types 1) Prokaryote • Lacks internal compartments. • No true nucleus. • Most are single-celled (unicellular) organisms. • Examples: bacteria

  13. Two Basic Cell Types 2) Eukaryote • Has several internal structures (organelles). • True nucleus. • Either unicellular or multicellular. unicellular example: yeast multicellular examples: plants and animals

  14. Characteristics of Prokaryotic Cells. surrounded by a membrane and cell wall has no membrane enclosed organelles

  15. Prokaryotic continued Cells come in multiple shapes: • cocci (round) • baccilli (rods) • spirilla(corkscrew) Some cells have external whip-like flagella for locomotion or hair like pili for adhesion

  16. baccilli coccus spirilla

  17. flagella pili

  18. Eukaryotes Animal Cell Plant Cell

  19. “Typical” Plant Cell http://waynesword.palomar.edu/images/plant3.gif

  20. “Typical” Animal Cell http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

  21. Eukaryotes

  22. Plasma Membrane – phospholipidbilayer A lipid/protein/carbohydrate complex, providing a barrier and containing transport and signaling systems. A selective barrier that regulates the substances that pass in and out of the cell.

  23. Nucleus – the brainand Nucleolus Double membrane surrounding the chromotinand the nucleolus. Pores allow specific communication with the cytoplasm. The nucleolus is a site for synthesis of RNA making up the ribosome.

  24. Mitochondria – the power house Surrounded by a double membrane with a series of folds called cristae which increases the surface area. Functions in energy production through metabolism called cellular respiration. Makes an energy molecule known as ATP. Contains its own DNA.

  25. Rough Endoplasmic Reticulum A network of interconnected membranes forming channels within the cell. Connects the nuclear membrane to the cell membrane. Covered with ribosomes (causing the "rough" appearance) which are in the process of synthesizing proteins for secretion or localization in membranes.

  26. Ribosomes – protein factories Protein and RNA complex responsible for protein synthesis – making proteins. Can be found on rough ER or floating free in the cytosol (cytoplasm).

  27. Smooth Endoplasmic Reticulum A network of interconnected membranes forming channels within the cell. A site for synthesis and metabolism of lipids. Also contains enzymes for detoxifying chemicals including drugs and pesticides.

  28. Golgi Apparatus and Vesicles A series of stacked membranes. Vesicles (small membrane surrounded bags) carry materials from the RER to the Golgi apparatus. Vesicles move between the stacks while the proteins are "processed" to a mature form. Vesicles then carry newly formed membrane and secreted proteins to their final destinations.

  29. Vacuoles Membrane surrounded "bags" that contain water and storage materials .

  30. The main function of these microbodies is digestion. Lysosomes break down cellular waste products and debris from outside the cell into simple compounds, which are transferred out into the cytoplasm as new cell-building materials. Lysosomes – suicide bag

  31. Microtubules Reinforces and gives support to the cell and its shape. Involved in separating chromosomes when a cell divides.

  32. Cell wall Plants have a rigid cell wall in addition to their cell membranes.

  33. Chloroplast Chloroplasts are specialized organelles found in plant cells. These organelles contain chlorophyll. They have a double outer membrane. Within the stroma are other membrane structures - the thylakoids and grana (singular = granum) where photosynthesis takes place.

  34. Prokaryotes & Eukaryotes • Similarities & differences • Both surrounded by plasma membrane, but very different • Prokaryotes – Archaebacteria and Eubacteria • Eukaryotes – everything else

  35. Plant & Animal Cells • Similarities • Both constructed from eukaryotic cells • Both contain similar organelles • Both surrounded by cell membrane

  36. Plant & Animal Cells • Differences • Plants have • Cell wall – provides strength & rigidity • Have chloroplasts, photosynthetic • Animals have • Other organelle not found in plants (lysosomes formed from Golgi) • Centrioles, important in cell division

  37. Homeostasis Balance between all life activities. Things that influence equilibrium: Size of particles Solubility in water Conditions in and out of the cell Structure of the membrane (pore size) Passive and active transport maintains homeostasis

  38. Diffusion The movement of molecules from an area of high concentration to an area of low concentration.

  39. Factors that Affect Diffusion • Concentration • Temperature • Pressure

  40. Special types of diffusion • Osmosis the special diffusion of water across a selectively permeable membrane. It is a passive transport (needs no energy) • Turgor Pressure the pressure that builds up in a plant cells as a result of the osmosis of water inward into a plant cell. This gives the plant firmness.

  41. Isotonic Solution

  42. Hypotonic Solution

  43. Hypertonic Solution

  44. Active Transport Movement from a lesser concentration to a higher concentration. It requires energy and goes against the gradient

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