Lesson 1 the cell


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Lesson 1 the cell

  1. 1. The Human Body A multicellular organism.The cell.
  2. 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. 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. 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. 5. Biomolecules  Rich in carbon ◦ Proteins: give structure..transport… muscle. ◦ Lipids: fat ◦ Carbohidrates: sugar ◦ Nucleic acids: form the nucleus. Genetic material.
  6. 6. What do all cells have in common?  Cellular membrane  Cytoplasm  Nucleus
  7. 7. Cell membrane  It is a thin layer that covers the cell and serves as a boundary between the cell and the surrounding.
  8. 8. Cytoplasm  Inner content of the cell mainly made of water and where different structures, called organelles, are found.
  9. 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. 10. Activity How many cells do you see in the image?
  11. 11. The cell: organelles
  12. 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. 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. 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. 15. Organelles: Vacuoles  Membranous vesicles which store dissolved substances as reserves or waste. Membrane of vacuoles in plant cells
  16. 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. 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. 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