Biology

• food test : sugar


  benedict- blue to brick red
• food test : starch


  iodine- brown to blue black
• food test: protein


  biuret- blue to purple
• food test: lipids 


  ethanol- clear to cloudy layer
• features and jobs of xylem:

  • transports water + minerals
  • transports one way
• features and jobs of phloem:

  • transports food made by photosynthesis
  • transports in both way (up and down)
• Viral disease: measles

  symptoms: fever/ red skin

  prevention: vaccination
• viral disease: HIV/AIDS


  symptoms: flu like

  prevention: condoms/ drug
• protists: Malaria


  symptoms: fever/ shaking

  prevention: prevent vectors from breeding
• aspirin originated from 


  willow
• digitalis originated from 


  foxgloves
• stimulus - receptor - sensory - relay - motor - effector - response
• Artery- carries blood away from the heart at high pressure.
• vein - carries blood to the heart
• Artery: oxygenated

  • small lumen
  • thick walls for high pressure
• Vein: deoxygenated blood

  • thin walls
  • valves
  • large lumen
• body - vena cava - right atrium - right ventricle - pulmonary artery - lungs
• lungs - pulmonary vein - left atrium - left ventricle - aorta - body
• pace makers are found in the right atrium
• aerobic respiration: uses oxygen
• anaerobic respiration : not enough oxygen
• human defence system:

  • skin - antimicrobial secretion
  • nose/ trachea - mucus
  • stomach - hydrochloric acid
• image size = real size x magnification
• difference between a prokaryotic + eukaryotic:

  • Both have cell membrane and cytoplasm
  • Eukaryotic has nucleus.
  • Prokaryotic has a cell wall
  • Prokaryotic has plasmids which has nucleus
• Sperm has many mitochondria to supply energy to move
• Sperm has acrosomes which contain digestive enzymes for breaking the outer layer of the egg
• Nerve cell has long axons to enable impulses to be carried over long distances quickly
• Muscle cell has contain lots of protein that slide over each other making fibre contract
• Root hair cell has large surface area to increase the rate of water absorption / taking in
• diffusion is the net movement of particles from an area of high concentration to an area of low concentration
• concentration gradient and temperature affect the rate of diffusion
• Osmosis is the movement of water from a high concentration to a low concentration through a partially permeable membrane
• Active transport is the movement of particles from an area of low concentration to an area of high concentration against a concentration gradient
• active transport happens in root hair cell and in the gut
• diffusion happens in the small intestine, leaves, gills
• advantage of stem cells: treat many diseases , replace damaged body part, 


  disadvantage of stem cells: scientist do not completely understand the process, hard to control, destruction of the embryo
• stomach produces hydrochloric acid to kill bacteria
• Small intestine absorbs nutrients from food and transports them to the bloodstream. Break down food into smaller molecules.
• Large intestine absorbs water from undigested food
• liver produces bile to help with the digestion of lipids