The Basics of Everything

• Electron Microscopes :

  Electron Microscopes allow us to see finer details (organelles, sub-cellular structures) due to their greater resolving power and higher resolution.
• Magnificatoin = Image size / Object size
• EUkaryotic cells = nucleus (plant and animal cells)

  Prokaryotic cells = NO nucleus (DNA is found in plasmids) (bacteria)
• Cell Membrane :

  • semi permeable
  • controls what enters and leaves
  • the 2nd outer layer
• Cell Wall

  • made of cellulose - provides rigid structure
• Cytoplasm :

  • chemical reactions take place
• Mitochondria

  • respiration takes place, releasing energy for the cell to function
• Ribosomes :

  • protein synthesis
• Plant cells contain :

  • chloroplast, which contains chlorophyll, which is where photosynthesis takes place
  • permanent vacuole : stores sap
• Diffusion is the movement of particles from an area of high concentration to an area of low concentration - down the concentration gradient.
• Rate of Diffusion and Osmosis can INCREASED by :

  • ↑ difference in concentrations
  • ↑ temp
  • ↑ surface area
• INGESTION : food enters mouth, teeth break down food physically / mechanically. Saliva contains amylase.
• The stomach contains HYDROCHLORIC ACID and ENZYMES that chemically digest food
• The Liver produces BILE, which is stored in the gall bladder, before going to the small intestine.

  Bile EMULSIFIES LIPIDS to form droplets, increasing their surface area
• Pancreas secretes AMYLASE which breaks down starch into glucose in the small intestine
• Assimilation : the movement of nutrients into cells
• Excretion / Egestion : waste is ejected through the anus
• The Teeth

  
• Four main types of teeth :

  • incisors (at the front)
  • canines (the sharp ones)
  • premolars (in front of the molars)
  • molars (very back)
• Enzymes are biological catalysts
• AMYLASE breaks down STARCH into GLUCOSE - found in small intestine and saliva
• PROTEASE break down PROTEINS into Amino Acids
• Lipases break down LIPIDS into GLYCEROL and FATTY ACIDS
• CARBOHYDRASES break down CARBOHYDRATES into SIMPLE SUGARS
• Enzymes :

  Substrates bind to an Active Site
• Rate of enzyme activity :

  Higher temp = increases activity until the enzyme denatures (active site changes shape)
• Carbs are needed for :

  • respiration to release energy
• Fats & Oils (Lipids) are needed for :

  • store of energy
• Proteins are needed for :

  • growth and repair
• Vitamins and Minerals :

  • vitamin c def: scurvy
  • vitamin d def: rickets (needed for healthy muscles & bones)
  • calcium needed for bones, iron for blood
• lack of calcium : osteoporosis
• lack of iron : anaemia
• fibre is needed for :

  healthy digestive system
• water is needed by every cell in your body
• Respiratory system order :

  trachea → bronchi → bronchioles → alveoli → Oxygen diffuses into the bloodstream and binds to the haemoglobin in red blood cells to be transported
• The Heart :

  • Deoxygenated blood enters through the Vena cava, into the right atrium
  • Right Ventricle
  • Pulmonary Artery to the lungs to be oxygenated
  • Comes back into the heart through the Pulmonary Vein (from the lungs)
  • Into left atrium
  • Into left ventricle
  • Out to the body through the aorta
• Left side of the heart has thicker walls because it has to pump blood to the whole body
• Away Arteries
• Valves : prevent blood flowing backwards
• Tricuspid and Bicuspid valve :

  • tricuspid - right
  • bicuspid - left
  • these valves are pushed open when the atria contract, but when the ventricles contract they are pushed shut to prevent blood flowing back into the atria