Biology

• Light microscopes


  Use light and lenses
• Light microscopes


  • See individual cells and structures
  • See subcellular
• Differentiation


  When a cell becomes specialised for its job
• Cells that differentiate in Mature Animals are mainly used for replacing and repairing, e.g. red blood cells
• Electron microscopes


  • Uses electrons to form an image
  • Higher magnification and resolution
  • Sees smaller things (eg plasmids)
• Prokaryotic cells


  More smaller and simpler structures (eg. bacteria cells)
• Eukaryotic cells


  More complex structures (eg. plant cells)
• What is diffusion?


  Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
• views agreeing with stem cell research 


  •embryos are usually unwanted

  •helping a patient is more important than the embryo
• Why are people against stem cell research?


  Ethics, religious beliefs, and concerns about the destruction of embryos.
• What is therapeutic cloning?


  Therapeutic cloning is the process of creating embryonic stem cells for medical purposes, such as generating tissues or organs for transplantation.
• stem cells cure diseases

  Stem cells from bone marrow can replace faulty red blood cells
• Embryonic stem cells:


  • turns into any cell

  • found anywhere in the embryo
• Adult stem cells


  • only found in bone marrow

  • cannot turn into any cell
• What are stem cells?


  Stem cells are undifferentiated cells that have the ability to develop into different types of specialized cells in the body.
• What is phloem?


  Plant tissue responsible for transporting nutrients and sugars throughout the plant.

  it has very few sub-cellular structures.
• What is xylem?


  Plant tissue that transports water and nutrients from the roots to the rest of the plant.

  Cells are long and joined end to end
• what are root hair cells specialised for?

  Absorption of water and minerals.

  Have a large surface area
• What is an organ system?

  a group of organs working together to perform a particular function
• What does muscular tissue do?

  Contracts to move
• What does glandular tissue do?


  Makes and secretes chemicals like enzymes and hormones
• What does epithelial tissue d?

  covers the inside of the gut
• What do villi have?


  • a single layer of surface cells

  • a very good blood supply to assist quick absorption
• What is the villi and where is it found?

  • inside the small intestine

  • increases the surface area
• What is alveoli?


  Air sacs in the lungs where gas exchange occurs.
• How are alveoli specialised?


  • large surface area

  • a moist lining

  • very thin walls

  • a good blood supply
• What is gas exchange?


  The process of exchanging oxygen and carbon dioxide between an organism and its environment.
• How are exchange surfaces adapted to maximise effectiveness?

  • thin membrane

  • large surface area

  • lots of blood vessels
• What is osmosis?


  Osmosis is the movement of water molecules from an area of lower solute concentration to an area of higher solute concentration across a semi-permeable membrane.
• What is active transpor?


  Active transport is the movement of molecules or ions across a cell membrane against their concentration gradient, requiring energy from ATP.
• Test for proteins 


  • biuret solution

  • turns purple
• How does bile emulsify fat?

  • breaks fat into tiny droplets

  •bigger surface area

  • makes digestion faster
• Test for starch 


  • drops of iodine solution

  • turns blue-black
• Test for lipids 


  • Sudan III

  • separates into two layers

  • top layer is red
• Test for sugars 


  • water bath at 75 degrees

  • Benedict’s solution

  • turns brick-red
• How does bile neutralise the stomach acid?

  • bile is an alkaline
  • neutralises the hydrochloric acid
  • the enzymes work best in alkaline conditions
• What is bile?

  • produced in liver
  • stored in gall bladder
  • released into the small intestine
• What are lipases?


  Convert lipids into glycerol and fatty acids
• What is lipase?


  Coverts lipids into fatty acids

  found in pancreas and small intestine
• what are proteases?

  • convert proteins into amino acids
  • found in the stomach, small intestine and pancreas