Biology Paper 1

• Active transport


  Movement of substances from a dilute solution to a more concentrated one against a concentration gradient, using energy from respiration
• Adult stem cell


  Type of stem cell that can form many types of cells
• Agar jelly


  Substance placed in petri dishes which is used to culture microorganisms
• Cell differentiation


  Cells become specialised
• Diffusion


  Spreading of particles of any substance in solution or gas, from an area of high concentration to an area of low concentration
• Eukaryotic cell


  Cell found in plants & animals, containing a nucleus
• Meristematic cell


  Cell that can differentiate into any plant cell
• Mitosis


  Type of cell division which produces two genetically identical daughter cells from one parent cell
• Prokaryotic cell


  Simple cell without a nucleus
• Animal cells


  • Eukaryotes (have a nucleus)
  • Cytoplasm (watery solution where chemical reactions take place)
  • Cell membrane (controls what molecules enter and leave the cell)
  • Ribosomes
  • Nucleus
  • Mitochondria
  • Cytoplasm
• Microscope


  • Eyepiece
  • Objective lens
  • 4x, 10x, 40x magnification
  • Coarse focusing dial
  • Stage
  • Lamp/mirror
  • Fine focusing dial
• Microscope use


  Total magnification = Eyepiece magnification x Objective lens magnification
• Osmosis experiment on plant tissue

  1. Peel potato

  2. Make 3 cylinders of potato

  3. Measure length and mass

  4. Put in tubes with 0.5M sugar solution, 0.25M sugar solution, and distilled water

  5. Leave overnight

  6. Measure length and mass again

  7. Calculate % change
• Diffusion


  Particles move down the concentration gradient, does not require energy
• Active transport


  Particles are moved against the concentration gradient, requires energy from respiration
• Eukaryotic cells have a cell membrane, cytoplasm, and DNA enclosed in a nucleus
• Prokaryotic cells have DNA in a single loop and are smaller than eukaryotic cells
• Plant cell


  • Cell wall
  • Cytoplasm
  • DNA loop
  • Chloroplast
• Sperm cell


  • Head
  • Long tail to swim
• Nerve cell


  • Long extensions to transmit signals
  • Branched extensions to connect to other nerves
• Xylem


  • Hollow tubes of dead tissue with holes
  • Transports water and minerals from roots to leaves
• Phloem


  • Transports glucose from leaves to other parts of the plant
• Root hair


  • Hair-like projections to increase surface area
  • No chloroplasts
• Cell differentiation is the process by which cells become specialised
• aorta


  Main artery that carries oxygenated blood from the left ventricle of the heart to the rest of the body
• artery


  Blood vessel that carries oxygenated blood away from the heart to the body's tissues
• atrium


  Upper chamber of the heart that receives blood flowing into the heart
• Magnification = Size of image / Real size of object
• ventricle


  Lower chamber of the heart that pumps blood out of the heart
• valve


  Structure that controls the flow of blood through the heart
• Types of diseases


  • Communicable
  • Non-Communicable
• Communicable disease


  Can be passed from person to person
• Non-Communicable disease


  Cannot be passed from person to person
• Tumour


  Mass of uncontrollable cells that divide
• Cancer


  Spreads through the bloodstream
• Benign


  Not cancerous
• Bacteria


  Releases toxins that damage cells and tissues
• Malaria


  Caused by a female mosquito protist, leads to fever and loss of blood. Prevented by vaccines and wearing long sleeves
• Secondary defences


  • White blood cells
  • Anti-toxins
• Lymphocytes


  Produce antibodies to mark pathogens