Science

• How is active transport different to diffusion and osmosis

  Active transport is the only process which moves particles from low to higher concentration and so requires energy
• What is the equation for photosynthesis

   carbon dioxide + water → glucose + oxygen
• How is aerobic and anaerobic respiration different

  Aerobic respiration occurs reacts glucose with oxygen and produces carbon dioxide and water. It is slower but releases more energy. Anaerobic respiration occurs without oxygen and produces lactic acid. It is faster but releases less energy
• Nucleus


  Controls the activities of the cell and contains genetic material
• What is the purpose of the cell membrane 


  It holds the cell together

  it controls what goes on and out of the cell
• What is the purpose of the ribosome

  It is where the proteins are made
• What are two differences with animal and plant cells

  It has a permanent vacuole

  Chloroplast - where photosynthesis occurs
• What is the purpose of the mitochondria

  Where most reactions for aerobic respiration take place
• 3 types of non-renewable energy sources

  Crude oil

  coal

  natural gas
• 3 renewable energy sources

  Wind energy

  hydropower

  solar energy
• What does renewable and non-renewable mean

  Renewable - never run out

  non-renewable - will run out
• What is the purpose of the cytoplasm

  Where most chemical reactions take place
• Cell


  The basic building blocks that make up large organisms
• Cell specialisation


  The process by which cells become specialised for a particular job
• Tissue


  A group of similar cells that work together to carry out a particular function
• Organ


  A group of different tissues that work together to perform a certain function
• Organs


  • Stomach
  • Liver
• Organ system


  A group of organs working together to perform a particular function
• Organ systems work together to make entire organisms
• Enzymes are chemicals produced by the body
• Salivary glands, liver, and pancreas are organs involved in digestion
• Digestion is a process that breaks down and absorbs food
• What is an enzyme 


  Makes chemical reactions work
• What does every enzyme have

  An active site
• What do enzymes need to work 


  The rught temp and ph
• What do digestive enzymes do

  Break down big molecules
• Enzymes


  What make you work
• Enzymes


  What make them (enzymes) work
• Enzymes


  • Catalysts produced by living things
  • Reduce the need for heat and we have ones to speed up the chemical reactions in the body
• Catalyst


  A substance which INCREASES the speed of a reaction without being CHANGED OR USED UP in the reaction
• Enzymes


  Are made up of chains of amino acids that are folded into a 3D shape which enzymes need to do their jobs
• Enzymes


  • Have special shapes so they can catalyse reactions
  • Usually involve things either being broken apart or joined together
  • Have a unique shape that fits onto the substance involved in a reaction
• Enzymes usually only catalyse reactions specified in the exam
• Substrate


  The substance that an enzyme acts on
• How enzymes work


  1. Substrate has to fit into the enzyme's active site

  2. If the substrate doesn't match the enzyme's active site, then the reaction won't be catalysed
• The active site changes shape as the substrate binds to it, this is called the induced fit model of enzyme action
• Changing the temperature


  Changes the rate of an enzyme-catalysed reaction
• Enzymes


  • Have an optimum temperature that they work best at
  • If it gets too hot, the enzyme can become denatured and the active site is changed so the substrate won't fit anymore
• Optimum pH


  The pH that enzymes work best at, often neutral pH 7 but not always
• If the pH is too high or too low, it interferes with the bonds holding the enzyme together and denatures the enzyme