Cell Biology

• Cell membrane


  Outer boundary of the cell
• Prokaryotic cells

  • Bacteria
• Prokaryotic cells


  • Genetic material not enclosed in a nucleus
  • Smaller than eukaryotic cells
• Prokaryotic cells


  Genetic material not enclosed in a nucleus
• Eukaryotic cells


  Contain their genetic material enclosed in a nucleus
• Cytoplasm


  Fluid inside the cell where organelles are suspended
• Eukaryotic cells


  • Contain genetic material enclosed in a nucleus
  • Have a cell membrane
  • Have cytoplasm
• Prokaryotic cells


  Do not have a nucleus
• Prokaryotic cells


  Smaller than eukaryotic cells
• Prokaryotic cells

  • Have a cell membrane
  • Have a cell wall
  • Have cytoplasm
• Animal and plant cells

  • Have a nucleus containing genetic material
  • Have a cell membrane
  • Have cytoplasm
• Plasmids


  Small rings of DNA found in bacteria
• Components of prokaryotic cells

  • Cell membrane
  • Cell wall
  • Cytoplasm
• Micro


  One millionth
• Dividing 1 meter into 100 equal parts

  1 centimeter is obtained
• Nano


  One billionth
• Milli


  One thousandth
• Dividing 1 centimeter into 10 equal parts

  1 millimeter is obtained
• Examples of sizes

  • German Shepherd is around 1 meter
  • Width of a little finger is around 1 centimeter
  • Tip of a ballpoint pen is around 1 millimeter
  • Typical human cell is around 10 to 20 micrometers
  • Molecule of hemoglobin is around 5 nanometers in diameter
• Describing the size of cells

  Use the prefixes centi, milli, micro, and nano
• Dividing a meter into 1 million equal parts

  1 micrometer is obtained
• Dividing a meter into 1 billion equal parts

  1 nanometer is obtained
• Prokaryotic cells are much smaller than eukaryotic cells
• Sizes in science

  • Based on the meter
• Objects and biology are often much smaller than a meter
• Centi


  One hundredth
• Mitochondria


  • Function: Site of aerobic respiration
• Animal cells are eukaryotes with genetic material enclosed in a nucleus
• Components of animal cells

  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
• Ribosomes are too small to be seen with a light microscope, requiring an electron microscope for viewing
• Nucleus

  • Function: Encloses the genetic material
• Cell membrane


  • Function: Controls the molecules that can enter and leave the cell
• Cytoplasm

  • Function: Watery solution where chemical reactions take place
• Proteins, synthesized by ribosomes, carry out various functions such as enzymes
• Ribosomes


  • Function: Sites of protein synthesis
• Cell sap


  The fluid inside a vacuole
• Animal cell specialisation


  • Most animal cells are specialised
  • They have adaptations which help them to carry out their particular function
• Cell differentiation

  When cells become specialised
• Sperm cell

  A specialised cell that joins with an ovum (egg cell) during fertilisation
• Ovum


  A specialised cell that is joined with a sperm cell during fertilisation