questions

• what are the four main features of blood?

  • plasma
  • platelets
  • white blood cells
  • red blood cells
• what is differentiation?

  the process in which a cell becomes specialised
• what are the specialisations of a red blood cell?

  • bi-concave for larger surface area
  • no nucleus for more space to carry haemoglobin
• what are the specialisations of nerve cells?

  • long, so they can conduct nerve impulses across the whole body
  • myelin sheath speeds up nerve impulses
  • dendrites allow nerve cells to communicate with other nerve cells
• what does the myelin (fatty) sheath do in a nerve cell?

  • insulation
  • keeps electrical current where it should be
  • stops twitching
• give two adaptations of a sperm cell

  • long tail = helps the sperm swim to the egg quicker
  • large number of mitochondria = releases energy to swim to the egg via respiration
• give an adaptation of a root hair cell

  • large surface area
  • helps diffuse water and minerals
• what are the main parts of a bacterial cell?

  • cell wall
  • cell membrane
  • slime capsule
  • plasmids
  • flagella
• what shapes are bacterial cells?

  • round
  • rod (cylinder)
  • spiral
• what do bacteria cells not have?

  • nucleus
  • chloroplast
  • mitochondria
• what is the calculation for magnification?

  magnification = image size / real size
• name the features of an electron microscope

  • samples must be dead
  • expensive to buy and operate
  • complex sample preparation
  • vacuum required
  • large and needs to be fitted
  • samples seen only in black and white
  • high magnification
• name the features of a light microscope

  • cheap to buy
  • small and portable
  • simple sample preparation
  • no vacuum required
  • samples can be living
  • relatively low magnification
  • samples can be seen in colour
• describe mitosis

  • chromosomes form
  • they line up at the equator of the cell
  • fibres pull them to the poles
  • cytoplasm and cell membrane divides and form two identical daughter cells = cytokinesis