B1 and B2

• Bacterial cells


  Much smaller than plant and animal cells
• Components of bacterial cells


  • Cytoplasm
  • Cell membrane
  • Cell wall
  • Bacterial DNA loop (not in a nucleus)
  • Plasmid DNA rings
• Bacteria may have more than one plasmid DNA ring
• Cell parts


  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
  • Cell wall
  • Chloroplasts
  • Permanent vacuole
  • Bacterial DNA
  • Plasmid (DNA)
• Nucleus


  Contains genetic material, which controls the activities of the cell
• Cytoplasm


  Most chemical processes take place here, controlled by enzymes
• Cell membrane


  Controls the movement of substances into and out of the cell
• Mitochondria


  Most energy is released by respiration here
• Ribosomes


  Protein synthesis happens here
• Cell wall


  Strengthens the cell - made of cellulose (not in bacteria)
• Chloroplasts


  Contain chlorophyll, absorb light energy for photosynthesis
• Permanent vacuole


  Filled with cell sap to help keep the cell turgid
• Bacterial DNA


  Loop of DNA NOT found in a nucleus
• Plasmid (DNA)


  Small ring of DNA often used as a vector in genetic modification
• Prefixes used by scientists

  • centi (cm) - x 10^-2
  • milli (mm) - x 10^-3
  • micro (μm) - x 10^-6
  • nano (nm) - x 10^-9
• Why do scientists use prefixes?

  To make very small numbers more manageable
• Bacterial cells are much smaller than plant and animal cells
• Bacterial DNA is a loop not found in a nucleus
• Image


  What is viewed through the microscope
• Object


  The ACTUAL specimen under the microscope
• Worked Example 1


  1. Magnified animal cell structure has a diameter of 6 mm

  2. Actual diameter of the structure is 0.15mm

  3. Calculate how many times the structure has been magnified
• Worked Example 2


  1. Actual length of a cell structure is 30μm

  2. Magnified 40 times

  3. Calculate the length of the magnified cell structure in mm
• Making a wet mount slide e.g. onion cells
• Drawing what you see
• Effectiveness of disinfectants and antibiotics on bacteria experiment
• Bacteria multiply by binary fission
• Bacteria can be grown in the lab
• Crop plants


  • With special features such as disease resistance
  • Can be cloned to produce large numbers of identical plants for farmers
• Crop plants


  • Potatoes
  • Strawberries
  • Dates
• Chromosomes


  Coiled strands of DNA molecules
• Gene


  A section of DNA that codes for a protein
• DNA


  Genetic material found in the nucleus that codes for proteins
• Chromosomes are found in the nucleus of cells
• A human body cell has 23 pairs of chromosomes
• Cell cycle


  1. Growth

  2. DNA synthesis

  3. Mitosis
• Mitosis


  Cell division used for growth, repair and asexual reproduction
• Animal cell


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

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
  • Cell wall
  • Chloroplasts
  • Permanent vacuole
• Bacterial cell


  • Cytoplasm
  • Cell membrane
  • Ribosomes
  • Bacterial DNA
  • Plasmid (DNA)
• Nucleus contains genetic material, which controls the activities of the cell