Biology 1.1

• Plant cell


  • Nucleus
  • Cell membrane
  • Cytoplasm
  • Mitochondria
  • Cell wall
  • Chloroplast
  • Vacuole
• Animal cell


  • Nucleus
  • Cell membrane
  • Cytoplasm
  • Mitochondria
• Nucleus


  Controls the whole cell and contains DNA
• Cell membrane


  Controls what goes in and out of the cell
• Cytoplasm


  Jelly-like substance, most chemical reactions happen here
• Mitochondria


  Site of respiration
• Cell wall


  Gives structure to the cell
• Chloroplast


  Contains chlorophyll, green disc-like structures where photosynthesis takes place
• Vacuole


  Contains cell sap/stores cell sap
• Total Magnification


  Total magnification of an object
• Total Anagnificat


  Total magnification of an object
• Magnification


  Ratio of image size to actual object size
• This is a fly. The actual eye size is 1000 pm.
• Calculating magnification


  1. Length of the eye is 15mm

  2. Eye size is 15,000 μm

  3. Image size is 15,000 μm

  4. Magnification = Image size / Actual size

  5. Magnification = 15,000 μm / 1000 μm = 15
• The picture shows the eye magnified (zoomed in) by 15 times or 15x
• Microscope parts


  • Stage
  • Focusing wheel
  • Eyepiece
  • Objective lens
  • Slide
  • Mirror
  • Base
• Specialised cells


  • Red blood cell
  • Sperm cell
  • Egg cell
  • Nerve cell
  • Ciliated cell
  • Root hair cell
  • Palisade cell
  • Xylem cell
• Red blood cell function

  Carries blood to and from the body, has no nucleus so can carry more oxygen, carries hemoglobin to transport oxygen
• Sperm cell function


  Has a tail to help it move around, contains mitochondria and a nucleus with father's DNA, produced in large numbers to increase fertilization
• Egg cell function


  Has a nucleus containing mother's DNA, contains cytoplasm for the early embryo, cell membrane changes after fertilization
• Nerve cell function


  Transmits electrical signals over long distances, joins to other cells, has a fatty myelin sheath surrounding it
• Ciliated cell function


  Tiny hair-like structures (cilia) beat to move the egg cell from the ovaries to the uterus, also moves dust and other particles
• Root hair cell function

  Absorbs water and minerals from the soil, gives structure to the plant as it grows, divides into smaller parts/branches that travel into the soil
• Palisade cell function


  Found in the top of a leaf, packed with chloroplasts to absorb sunlight for photosynthesis, has a large surface area
• Xylem cell function


  Transfers water from the roots to other parts of the plant, gives support to the plant with their thick walls
• Diffusion


  The net movement of particles from an area of high concentration to an area of low concentration, a passive process that doesn't require energy
• Factors affecting diffusion rate

  • Higher temperature gives particles more kinetic energy
  • Larger concentration gradient has more particles to speed up the rate
  • Shorter distance has less room for diffusion to cover
  • More concentration means more particles will move
• Active transport


  The movement of particles from an area of low concentration to an area of high concentration, requires energy to happen and goes against the concentration gradient
• Osmosis


  The diffusion of water molecules from an area of high water concentration (diluted) to an area of low water concentration (concentrated), a passive process that doesn't require energy, happens through a partially permeable membrane
• Hypotonic


  When water enters the cell by the vacuole in osmosis, causing the vacuole to swell and push against the cytoplasm and cell wall, making the cell turgid
• Hypertonic


  When water leaves the cell by the vacuole in osmosis, causing the vacuole to reduce in size and the cytoplasm to pull away from the cell wall, making the cell plasmolysed
• Isotonic


  When there is the same amount of water inside the vacuole and outside the cell, so there is no movement in or out of the cell
• Animal cells rely on the water being isotonic, otherwise they will either burst (hypotonic) or shrink (hypertonic)