Cell Biology

• Required Practical


  Micy Fired Practical
• Specialised Cells


  • When all changes to became a specialand citie
  • Specialized Fanation
• Prokaryotic and Eukaryotic Cells

  Eukaryotic cells are membrane-bound and more complex, plant and animal cells are eukaryotic, prokaryotic cells like bacteria do not have membrane-bound organelles
• Prokaryotic cell


  • Bacterial cell
• Animal Cell


  • Ribosomes
  • Organelles and Nucleus
• Plant Cell


  • Cell wall
  • Chloroplasts
  • Vacuole
• Investigating the Effect of Antibiotics on Bacterial Growth

  1. Place paper discs that have been soaked with different antibiotics on an agar plate that has bacteria on it

  2. The antibiotic that causes the largest inhibition zone is the most effective at killing the bacteria

  3. Use sterile water on a disk as a control

  4. Leave in an incubator for 48 hours at 25C
• Dependent variable


  Change in mass
• Control variable


  Volume of solution, temperature, surface area of the potato
• The potato in the sugar solution will lose water and so will have a decrease in mass, the potato in the pure water solution will gain mass
• Culturing Microorganisms in the Lab

  1. Use inoculating loops to add the bacteria to the agar jelly which contains nutrients

  2. The cultures are kept at 25C to prevent the growth of any harmful bacteria
• Bacterial Cells


  • Do not have a true nucleus, just have a single strand of DNA that floats in the cytoplasm
  • Contain a plasmid
• Prokaryotic cell reproduction

  Binary fission - the cell divides into two
• Microscopy Required Practical

  1. Preparing a slide

  2. Using a light microscope

  3. Drawing any observations - use a pencil and label important observations
• Chromosomes and Mitosis

  Genetic DNA has to be copied/replicated before the cell carries out mitosis
• Light microscope

  • Eyepiece
  • Stage
  • Clips
  • Light
  • Focusing wheels
• Osmosis and Potato Practical

  1. Independent variable - concentration

  2. Dependent variable - change in mass

  3. Control variables - volume of solution, temperature, time, surface area of the potato
• Stem Cells

  • Can differentiate into many cell types
  • Used for regenerative medicine, growing nerve cells, treating blood disorders
• Embryonic stem cells are more potent than adult stem cells
• The potato in the sugar solution will lose water and so will have less mass at the end; the potato in the pure water solution will gain water
• Stem Cells in Plants

  • Found in the meristem tissue at the tips of roots and shoots
  • Can produce clones of the plant
• Culturing Microorganisms in the Lab

  1. Use agar jelly which contains nutrients

  2. The bacteria will form colonies on the agar

  3. Use inoculating loops to add the bacteria to the agar jelly

  4. Microorganisms are kept at 25°C to prevent the growth of any harmful bacteria
• Alveoli

  Small air sacs in the lungs where gas exchange occurs
• Diffusion


  Movement of particles from a region of high concentration to a region of low concentration
• Investigating the Effect of Antibiotics on Bacterial Growth

  1. Place paper disks that have been soaked with different antibiotics on an agar plate that has bacteria on it

  2. The antibiotics should diffuse on to the agar

  3. The most effective antibiotic at killing the bacteria will have the largest inhibition zone

  4. Use a control that has sterile water on the disk

  5. Leave in an incubator for 48 hours at 25°C
• Osmosis


  Movement of water molecules from a region of high water concentration to a region of low water concentration
• Differentiation


  When a cell changes to become a specialised cell
• Micrometre to millimetre


  Divide by 1000
• Specialised Cells


  • Sperm
  • Nerve
  • Muscle
  • Root hair
  • Phloem
  • Xylem
• Standard form: 0.001 = 1 x 10^-3, 5.6 = 5.6 x 10^0, 0.0056 = 5.6 x 10^-3
• Area = π x r^2
• Sperm


  • Streamlined head, long tail, lots of mitochondria to provide energy
• Use a ruler to measure the diameter and then halve to find the radius
• Nerve


  • Long to cover more distance, has branched connections to connect in a network
• Muscle

  • Long and contain lots of mitochondria for energy
• Root hair

  • A large surface area to absorb more water
• Phloem


  • Pores to allow cell sap to flow, cells are long and joined end-to-end
• Xylem


  • Hollow in the centre, tubes through the plant, are joined end-to-end
• Eukaryotic cells


  Have membrane-bound organelles, e.g. plant cells, animal cells and fungus cells
• Prokaryotic cells


  Do not contain a nucleus, e.g. a bacterial cell