Lesson 1 the cell

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  • 1. The Human Body A multicellular organism.The cell.
  • 2. From cells to organisms  Human beings are composed of biomolecules.  They are made up of cells.  They perform 3 vital functions: ◦ Nutrition ◦ Reaction to stimuli ◦ Reproduction
  • 3. Cell size  Microscopic objects are meassured in: ◦ μm = 10-3 mm ◦ nm = 10-6 mm  These are not visible with a naked eye.  Eye resolution is 0.2 mm ◦ If two objects are separated by a smaller distance, we will see them as one. Exercise: If an object meassures 1 mm, how many micrometers does it meassure? And how many nanometers?
  • 4. Activity 5 cm Image increased: 1500 times How large is the Paramecium in reality? 5cm 1500 = 0,0033 cm How many µm is that? 33 µm
  • 5. Biomolecules  Rich in carbon ◦ Proteins: give structure..transport… muscle. ◦ Lipids: fat ◦ Carbohidrates: sugar ◦ Nucleic acids: form the nucleus. Genetic material.
  • 6. What do all cells have in common?  Cellular membrane  Cytoplasm  Nucleus
  • 7. Cell membrane  It is a thin layer that covers the cell and serves as a boundary between the cell and the surrounding.
  • 8. Cytoplasm  Inner content of the cell mainly made of water and where different structures, called organelles, are found.
  • 9. Organelles: Nucleus  It is the largest and most visible structure in the cell. It’s shaped like a sphere and normally in the center of the cell. It contains the material necessary to control all cell functions.  Nuclear envelope: made of a double membrane which has pores that allow the exchange of substances  Chromatin: filaments of genetic material which has the information that controls how the cell functions  Nucleolus: The ribosomes are synthesized in here  It’s structure changes depending on the phase of the cell cycle. The chromatin condenses into structures called chromosomes during cell division. CONTROL
  • 10. Activity How many cells do you see in the image?
  • 11. The cell: organelles
  • 12. Organelles: Mitochondria • All cells need mitochondria to obtain energy from nutrients • Mitochondria have an oval shape with a double membrane. • The cell obtains energy from small organic molecules using oxygen through a process called cellular respiration • http://www.shmoop.com/biology-cells/botw/resources?d=http://multimedia.mcb.harvard.edu/ With OXYGEN Respiration http://www.youtube.com/watch?v=xbJ0nbzt5Kw&feature=relmfu http://www.youtube.com/watch?v=3y1dO4nNaKY&feature=relmfu
  • 13. Organelles: Endoplasmic Reticulum • It’s made of membrane canals and sacks that extend throughout the cytoplasm with grain like structures called ribosomes. • Rough ER • In the reticulum many different substances are produced. • The ER without ribosomes is the Smooth ER.
  • 14. Organelles: Lysosomes • Membrane bound vesicles that transform complex structures into simpler ones. • Some nutrients reach the cell already transformed in small molecules. If not they are digested into smaller molecules by the lysosomes.
  • 15. Organelles: Vacuoles  Membranous vesicles which store dissolved substances as reserves or waste. Membrane of vacuoles in plant cells
  • 16. Organelles: Ribosomes  Small particles found loose in the cytoplasm or attatched to the ER membrane.  They synthesize proteins.  They are produced in the nucleolus.
  • 17. Organelles: Centrioles  2 hollow ciliders which walls are made of filaments.  They are in charge of moving the cytoskeleton and play a main role in cell division.
  • 18. Organelles: cytoskeleton  Group of filaments that are distributed making a network around the cytoplasm.  Most of the time cells respond with movements to stimuli.  The structures responsible for this movement are the filaments of the cytoskeleton