Organisation

• Cells are the basic unit of life
• Tissue is a group of similar cells that work together to perform a specific function
• Organelles ➔ cells ➔ tissues ➔ organs ➔ organ systems
• Organs are made up of different types of tissue working together to carry out a particular function.
• The human body has eleven major organ systems: nervous, circulatory, respiratory, digestive, skeletal, muscular, excretory, endocrine, reproductive, integumentary, immune.
• why can't we make our cells even warmer to increase the rate of reactions?


  Heating our cells more would require a lot of energy

  Higher temperatures could damage our cells

  Higher temperatures would also speed up non-useful reactions
• A catalyst is a substance that increases the speed of a chemical reaction without being used up or changed in the process.
• enzyme


   biological catalysts.

   large proteins, so made from a long chain of amino acids.
• active site


  special region of an enzyme that binds to the substrate
• for an enzyme to catalyse a reaction, the active site of the enzyme must be _____________ to the substrate. 


  complementary
• The lock and key model


  idea that active site of an enzyme has to be complimentary to the shape of the substrate for them to catalyse the reaction
• the induced fit model


  for an enzyme to catalyse a reaction, the enzymes active site actually changes shape slightly as it binds to the substrate
• optimum (enzymes)


  The temperature at which enzyme activity is highest
• What is pH?


  measure of acidity
• what does an extremely high pH do to enzymes

  denatures them
• The shape of an enzyme is crucial for its activity

  Enzymes break down food during digestion
• High temperatures start to break the bonds holding the enzyme together 

  This causes the enzyme and it's active site to change shape

  This means the enzymes active site will no longer be complementary to the substrate 
• why do we need carbohydrates?


  to provide energy for chemical reactions
• fats and oils are ______


  lipids
• why do we need lipids?

  • to insulate us and regulate our body temperature
  • to provide energy for our chemical reactions
• 1. Starchy foods like potatoes, bread, and pasta contain a lot of carbohydrates.
  2. Meat, fish, and legumes contain a lot of proteins.
  3. Cheese, nuts, and avocados contain a lot of lipids.
• protein


  important for growth and producing new cells
• what is important for strong bones?


  calcium
• scurvy


  lack of vitamin C
• why do we need iron?

  iron is an important component of haemoglobin 

  Haemoglobin is the protein in red blood cells that allows them to transport oxygen around the body

  A lack of iron (and hence haemoglobin), can lead to anaemia, where we can't transport enough oxygen to our tissues. 
• why do we need fibre


  to help food ove through our intestines
• 3 Ways we lose WATER from our body

  Urinating, Breathing, Sweating
• anaemia


  cant transport enough oxygen to our tissues
• biological molecules are


  lipids, carbohydrates, proteins
• Carbohydrates are broken down in ...

  mouth and small intestine
• glucose is a monomer
• glycogen is a polymer
• amino acids


  monomers that join together to form proteins
• proteins are made from

  hydrogen, oxygen, carbon, nitrogen
• Proteins are broken down in...

  small intestine, stomach
• Lipids are made from a single glycerol molecule and three fatty acid molecules.
• lipids are broken down in...

  small intestine
• Starch is a polymer of glucose, produced by plants.
• Starch is broken down by the enzyme amylase into maltose molecules. These are then broken down further by maltase into glucose. 
• where is amylase produces

  small intestine, salivary glands, pancreas