Cell Structure

• 2 Types of Cells

  
  

  Eukaryotic (Plant and Animal)

  Prokaryotic (Bacteria)
• Nucleus

  Controls all activities of the cell
• Cytoplasm

  A liquid gel in which most of the chemical reactions take place
• Cell membrane

  Controls what passes in and out of the cell
• Mitochondria

  Structures in the cytoplasm where most of the energy is released during respiration
• Ribosomes

  Where protein synthesis occurs and synthesis for all other proteins in the cell
• Cell wall

  Made of cellulose, it strengthens the cells and gives it support
• Chloroplasts

  They absorb energy from the sun to make food by photosynthesis
• Permanent vacuole

  A space in the cytoplasm filled with cell sap that keeps the cells rigid to support the plant
• Specialised cells

  Cells specialised to carry out a particular function
• Adaptations of root hair cells

  • Provide large surface area to increase rate of absorption
• Function of root hair cell

  Enables plants to take in water and mineral salts
• Adaptations of sperm cell

  • It has a middle section full of mitochondria to release energy
• Function of sperm cell

  To fertilise egg cells
• Tail on sperm cell

  To swim
• Adaptations of red blood cells

  • Cytoplasm contains haemoglobin to transport oxygen
  • No nucleus - can contain more haemoglobin
  • Biconcave shape to maximise surface area
• Function of red blood cell

  To carry oxygen
• Red blood cells do not have a nucleus
• Function of nerve cell

  To send nerve impulses around the body
• Equation for magnification

  Magnification = size of image (I) / actual size (A)
• Specialised cells grouped together

  Form a tissue
• Stem cells

  Unspecialised cells that can change to different types of cells
• Where stem cells are found - animals

  Human embryos and adult bone marrow
• Where stem cells are found - plants

  Meristems of plants
• Disadvantages of stem cells

  • Use of embryos is unethical
  • Embryonic stem cell research = murder
  • Immune system might recognise stem cells as foreign and be rejected and die
• Bacteria cell(Prokaryotic)

  No nucleus, genetic material is a single loop of DNA, cytoplasm, cell membrane, cell wall
• What are the 2 types of microscopes?

  • Light microscope
  • Electron microscope
• Why are electron microscopes better?

  They have a higher magnification, so you can see the organelles inside the cells in more detail
• Advantages of stem cells

  • Could replace faulty cells in sick people
  • Could be used to treat paralysis or diabetes
• Function of phloem and xylem cells

  • BOTH transport substances