Bio- Paper 1

• Light microscope


  • Uses light to magnify objects
  • Lower resolution
• Electron microscope


  • Uses electrons to magnify objects
  • Higher resolution
• Parts of a microscope


  • Eyepiece
  • Objective lens
  • Coarse focus
  • Fine focus
  • Arm
  • Stage
  • Light source
• Animal cell organelles


  • Cell membrane
  • Nucleus
  • Mitochondria
  • Ribosomes
  • Cytoplasm
• Plant cell organelles


  • Cell wall
  • Cell membrane
  • Nucleus
  • Mitochondria
  • Ribosomes
  • Cytoplasm
  • Chloroplast
  • Vacuole
• Cell membrane


  Controls what goes in and out of the cell
• Nucleus


  Contains DNA and controls the cell
• Mitochondria


  Site of respiration
• Ribosomes


  Site of protein synthesis
• Cytoplasm


  Site of chemical reactions
• Vacuole


  Contains cell sap and provides structure
• Cell wall


  Provides strength and support
• Chloroplast


  Site of photosynthesis
• Specialised animal cells


  • Red blood cell
  • White blood cell
  • Muscle cell
  • Sperm cell
• Red blood cell


  • No nucleus
  • Biconcave shape
  • More space to carry oxygen
• White blood cell


  • Irregular shape
  • Helps fight infection
• Muscle cell


  • Many mitochondria
  • Provides energy for contraction
• Sperm cell


  • Flagellum
  • Provides energy for swimming
• Specialised plant cells


  • Root hair cell
  • Xylem
  • Phloem
• Root hair cell


  Increases surface area for absorption of water and minerals
• Xylem


  Transports water and minerals up the plant
• Phloem


  Transports food (sugar) around the plant
• Diffusion


  Net movement of particles from high concentration to low concentration down a concentration gradient
• Osmosis

  Net movement of water from an area of high water concentration to an area of low water concentration through a partially permeable membrane
• Active transport


  Movement of substances from low concentration to high concentration through a partially permeable membrane, requiring energy
• Hypotonic


  If the concentration inside the cell is higher than the outside, the cell may burst
• Hypertonic


  If the concentration outside the cell is higher than the inside, the cell may shrivel
• Isotonic


  If the concentrations inside and outside the cell are the same, there is no net movement of water
• Mitosis


  Cell division process where a cell replicates its 46 chromosomes and divides into two identical daughter cells
• Cytokinesis


  The division of the cytoplasm to form two daughter cells after mitosis
• Stem cells


  • Able to divide by mitosis to form new cells
  • Able to differentiate into specialised cell types
• Types of stem cells


  • Adult stem cells
  • Embryonic stem cells
  • Plant stem cells
• Adult stem cells


  Found in bone marrow, can only differentiate into certain cell types
• Embryonic stem cells


  Taken from spare embryos, can differentiate into any cell type
• Plant stem cells


  Found in meristems at tips of roots and shoots, can differentiate into any plant cell
• Levels of organisation


  • Cells
  • Tissues
  • Organs
  • Organ systems
  • Organism
• Tissues


  Groups of cells working together to perform a particular function
• Organs


  Groups of tissues working together to perform a particular function
• Organ systems


  Groups of organs working together to perform a particular function
• Organism


  A living thing made up of organ systems