topic 2 organisation

• what are organelles?


  the parts that make up a cell
• what are tissues?


  a group of similar cells that work together to carry out a particular function
• examples of tissues?


  epithetlical cells make up epithetlical tissue which covers the bodies surface, muscle cells make muscle tissue which contacts and relaxes our body
• organ definition


  a group of different tissues that work together to perform a particular function. eg, epithetlical tissue makes the stomach, muscle tissue makes the pancreas
• organ systems


  a group of organs that work together to perform a particular function. eg, liver+stomach+pancreas= digestive system
• organism definition 


  multiple organ systems that work together to form an organism
• in order for a living organism to function it will carry out many chemical reactions
• most chemical reactions are naturally slow
• we can increase rate of reaction by increasing temperature
• the problems with increasing temperature to speed up chemical reaction

  requires alot of energy, can damage cells, speed up none useful reactions
• the best way to speed up chemical reactions is with a catalyst
• what is a catalyst?


  a catalyst is a substance that increases the speed of reaction without being changed or used up in the process
• what is an enzyme?

  a certain type of catalyst that is made by living organisms
• enzymes are large proteins made up of amino acids, depending on what form amino acids are in they will create a unique enzyme
• enzymes have a active site which is complementary to the substances
• if the substrate doesn't fit the active site of an enzyme then the reaction wont be catalysed
• the 2 models of enzyme reaction

  lock and key model, induced fit model
• what is the lock and key model?

  when scientists thought that the substrate had to fit perfectly into the active site
• what is the induced fit model?

  the enzyme actually changes shape slightly as it binds to the substrate
• what are 2 factors effecting enzymes?

  temperature and pH
• what does the term optimum mean for enzyme temperature?

  the temperature which enzyme activity is highest
• what is pH?


  a measure of acidity
• how does temperature effect enzymes?

  high temperature start to break apart the bonds holding the enzymes together, active site starts to change shape, if the shape change enough the enzyme wont be able to bind with the substrate
• what effect does extremely high pH have on enzymes?

  denatures them
• how does pH effect enzymes?

  some of the bonds that hold the enzyme together start to break, the active site starts to change shape, eventually the active site changes shape so much that the substrate cant fit
• what does optimal mean in pH?


  when the enzyme works best
• what are carbohydrates made from?

  carbon, hydrogen and oxygen
• example of a monomer

  glucose
• monomers can join together to make carbohydrate polymers
• an example of polymers

  starch
• the breakdown of complex carbohydrates into simple carbohydrates (simple sugars) are carried out by enzymes in the mouth and small intestine
• what are proteins made up of?


  long chains of amino acids bonded together
• a protein is a polymer, amino acids that it is made up from are monomers
• what are amino acids made up of?

  carbon, hydrogen, oxygen and nitrogen
• enzymes in the stomach and small intestine break proteins down into amino acids
• what are lipids?


  fats and oils
• what are lipids made up from?

  a single glycerol molecule attached to three fatty acid molecules
• the length and structure of the fatty acid molecule determine if it is a fat or oil lipid
• what are lipids made up from?

  carbon, hydrogen and oxygen atoms
• lipids are not polymers but carbohydrates and proteins are