Crash Course Biology


  1. That’s Why Carbon Is A Tramp Crash Course Biology #1
    1. Carbon is abundant as CO2 in atmosphere
    2. Also it’s small, not aggressive
    3. Needs 4 electrons to fill it’s outer shell. Forms covalent(sharing e-) bonds for it
  2. Water – Liquid Awesome Crash Course Biology #2
    1. H2O covalend bond
    2. H has slight +ve charge and O has slight -ve causing attraction b/w molecules and hence high cohesion and surface tension
    3.  Adhesion of water to other surfaces like Glass is greater than cohesion b/w its own molecules causing capillary action etc.
    4. Cohesion also makes water a good solvent. Substances that dissolve in water (ie are able to overcome the cohesive attraction b/w water molecules) are charged/ionic and called Hydrophilic. While those that cannot coz they’re neutral are Hydrophobic
    5. It has high heat capacity
  3. Biological Molecules – You Are What You Eat Crash Course Biology #3
    1. Molecules that allow for life as we know it to exist by providing:
      1. Instructions to function and reproduce: Proteins.
        1. They are made up of 20 types of Amino Acids( Amino Group NH2 + Carboxyl Group COOH):
        2. Nitrogen cannot be made in body, so has to be ingested by eating protein rich food like Egg White
        3. Each of 20 amino acids have different characteristic
        4. Amino Acid (AA) chains are called Polypeptides
        5. We can;t make 9 of the 20 AAs. So body breaks down protein from food to these 9 AAs and uses them to form the proteins it needs
        6. Types of Proteins:
          1. Enzymes
          2. Antibodies
          3. Protein Hormones and Endorphines
      2. Energy (Sources and Storage):  Carbohydrates:
        1. Made of sugars
          1. Simple Sugar ie Monosaccharide
            1. Glucose: Comes from sun, as all bioligical energy is captured from the sun by plants in form of Glucose thru photosynthesis. Any cell that needs energy gets it from stored glucose using respiration
            2. Fructose
          2. Complex Sugars, like Disaccharides
            1. Sucrose
          3. More Complex like Polysaccharides. These are used to store energy
            1. Cellulose: Eg Grass. Humans cannot digest it
            2. Starch: Eg.
              1. Bread is made from Amulose which is similar to cellulose
              2. Plant Roots
              3. Tubers (Tubers are various types of modified plant structures that are enlarged to store nutrients. ) Eg. Potato
              4. Flesh of Fruits
              5. Seeds of wheat plant that are crushed to make Flour
        2. Humans store extra carbs as:
          1. Short Term (1-2 day): Glycogen in liver and
          2. muscles, ready to use
          3. Long Term: Fat, Lipid. Fat is Glycerol+ Fatty Acid. Eg
            1. Trygliceride as 1G + 3 FA in Butter and Oil. Triglicerides can be
              1. Saturated(with H):Does not have any double bonds so packs tightly and forms solids at room temp,
              2. Unsaturated(without extra H): Oils
                1. TransFat: Not natural. Unsaturated Fatty Acids (FA) that have different structure
                2. Omega3 FA:  Unsat at the 3rd position
            2. Phospholipid: 1G + 2FA + 1Phosphate. Make up cell membrane as one end is hydrophilic and other hydrophobic
            3. Steriods: 4 C rings:
              1. Cholesterol:
                1. makes Cell wall
                2. Can turn into lipid hormones
  4. Eukaryopolis – The City of Animal Cells Crash Course Biology #4
    1. Animals and Plants are made of Eucayotic cells ie cells that have:
      1. Nucleus containing DNA
      2. Organelles with specialized functions
      3. Cell Boundary: Rigid Cellulose Wall for plants vs Flexible Membrane for animals that allows animals to form tissues and organs etc allowing nerves and movement, all of which is not possible in plants .
    2. Cell has following organelle:
      1. Cilia (like lung Cell) or Flagella(like Sperm Cell)
      2. Cell Membrane: It has selective permiability to control what can come in or go out
      3. Cytoplasm: Water + Nutrients filling the cell + Protein Cytoskeleton to reinforce the structure
      4. Endoplasmic Reticulum: Carry stuff around through membranes. Also help make lipids and
      5. Ribosome: Make/Synthesises proteins from Amino Acids
      6. Golgi Apparatus: Post Office  ie packaging of proteins made by Ribosome and delivering them to wherever needed. Can also cut proteins into hormones and join carbs and proteins to form molecules Eg. Snot/Phlem
      7. vessicles: Package that Golgi sends out to different part of cell or outside cell
      8. Lysosome: waste treatment plant and recycling
      9. Nucleus: Stores DNA and makes laws like what protein to make and how much by reading the DNA
        1. Chromatin: Holds the DNA. Divides into rod shaped chromosones (47 types in humans) when cell divides, each containing DNA strand
        2. Nulcleoplasm
        3. Nucleolus: Makes ribosomal RNA and then rRNA + Proteins = Ribosomes. ALso makes messanger or mRNA to send msg to ribosomes which carry out orders in rest of the cell
      10. Mitochondria: Power Plant. Use respiration to get energy from Carbs/Fats and converted to ATP
        1. These were not a part of animal cell originally but instead were seperate bacterium cell and injected
        2. Hence they have their own repro and DNA. Note that human egg has mother’s Mitochondial DNA and that’s what gets passed to the progeny. Scientists can track our M DNA to a single Mitocondial Eve 200K yrs ago in Africa
  5. In Da Club – Membranes & Transport Crash Course Biology #5
  6. Plant Cells Crash Course Biology #6
  7. ATP & Respiration Crash Course Biology #7
  8. Photosynthesis Crash Course Biology #8
  9. Heredity Crash Course Biology #9
  10. DNA Structure and Replication Crash Course Biology #10
  11. DNA, Hot Pockets, & The Longest Word Ever Crash Course Biology 
  12. Mitosis Splitting Up is Complicated – Crash Course Biology #12
  13. Meiosis Where the Sex Starts – Crash Course Biology #13
  14. Natural Selection – Crash Course Biology #14
  15. Speciation Of Ligers & Men – Crash Course Biology #15
  16. Animal Development We’re Just Tubes – Crash Course Biology #16
  17. Evolutionary Development Chicken Teeth – Crash Course Biology #17
  18. Population Genetics When Darwin Met Mendel – Crash Course Biology #18
  19. Taxonomy Life’s Filing System – Crash Course Biology #19
  20. Evolution It’s a Thing – Crash Course Biology #20
  21. Comparative Anatomy What Makes Us Animals – Crash Course Biology #21
  22. Simple Animals Sponges, Jellies, & Octopuses – Crash Course Biology #22
  23. Complex Animals Annelids & Arthropods – CrashCourse Biology #23
  24. Chordates – CrashCourse Biology #24
  25. Animal Behavior – CrashCourse Biology #25
  26. The Nervous System – CrashCourse Biology #26
  27. Circulatory & Respiratory Systems – CrashCourse Biology #27
  28. The Digestive System CrashCourse Biology #28
  29. The Excretory System From Your Heart to the Toilet – CrashCourse Biology #29
  30. The Skeletal System It’s ALIVE! – CrashCourse Biology #30
  31. Big Guns The Muscular System – CrashCourse Biology #31
  32. Your Immune System Natural Born Killer – Crash Course Biology #32
  33. Great Glands – Your Endocrine System CrashCourse Biology #33
  34. The Reproductive System How Gonads Go – CrashCourse Biology #34
  35. Old & Odd Archaea, Bacteria & Protists – CrashCourse Biology #35
  36. The Sex Lives of Nonvascular Plants Alternation of Generations – Crash Course Biology #36
  37. Vascular Plants = Winning! – Crash Course Biology #37
  38. The Plants & The Bees Plant Reproduction – CrashCourse Biology #38
  39. Fungi Death Becomes Them – CrashCourse Biology #39
  40. Ecology – Rules for Living on Earth Crash Course Biology #40