organisation

• Organelles


  Also called subcellular structures, the parts that make up a cell like the nucleus, ribosomes, and mitochondria
• Organelles

  • Each individual organelle has a specific role to play
  • When combined, multiple organelles will form a single cell
• Cells


  Come in all sorts of shapes and sizes and contain different combinations and numbers of organelles
• Specialized cells


  Different types of cells like epithelial cells, muscle cells, and glandular cells
• Tissues


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


  • Epithelial tissue
  • Muscle tissue
  • Glandular tissue
• Organs


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


  • Stomach
  • Pancreas
  • Liver
• Organ systems


  A group of organs that work together to perform a particular function
• Organism


  The highest level, with multiple organ systems working together
• There are many more examples of each level of organization than mentioned
• There are about 12 different organ systems including the immune system, nervous system, respiratory system, endocrine system, and urinary system
• Enzymes

  Catalysts made by living organisms
• Enzymes


  • They are large proteins made up of long chains of amino acids
  • They can fold into different shapes, each shape catalyzing a particular chemical reaction
• How enzymes work


  1. Enzyme has an active site with a unique shape

  2. Substrate fits into active site

  3. Enzyme speeds up the chemical reaction
• Substrate


  Reactant in a chemical reaction
• Products


  Smaller pieces that a substrate is broken into
• Enzymes speed up chemical reactions without being consumed or changed in the process
• Lock and key model

  Original model where substrate had to fit perfectly into active site
• Induced fit model


  More realistic model where enzyme changes shape slightly to better fit the substrate
• The active site of an enzyme is complementary to the substrate
• The induced fit model is like putting your hand into a rubber glove - the glove molds to your hand
• How temperature and pH affect the functioning of enzymes and the rate of enzyme controlled reactions

  1. Temperature increases

  2. Rate of reaction increases

  3. Temperature reaches 37 degrees

  4. Rate of reaction starts to drop rapidly

  5. Enzyme becomes denatured at around 45 degrees

  6. Optimal temperature is 37 degrees
• Denatured

  Enzyme's shape changes so it can no longer bind to the substrate and catalyze the reaction
• Optimal temperature

  Temperature at which the rate of reaction is highest
• How pH affects enzymes

  1. pH gets too high or too low

  2. Bonds holding the enzyme together start to break

  3. Active site changes shape

  4. Substrate can no longer fit

  5. Enzyme becomes denatured
• Optimal pH

  pH at which the enzyme works best
• Most enzymes in our body work best at neutral pHs of around 7
• Enzymes that work in the stomach have an optimal pH of around 2 because they need to function in the stomach's acidic environment
• Enzymes

  Essential for helping us break down the large molecules that we eat into the much smaller soluble molecules that we can absorb through our intestinal lining
• Main groups of nutrients to be broken down

  • Carbohydrates
  • Proteins
  • Fats
• Carbohydrates

  Found mainly in foods like pasta, potatoes and rice, used by the body mainly as an energy source
• Starch

  The main type of carbohydrate
• Breakdown of starch

  Broken down by the enzyme amylase into smaller sugars such as maltose
• Places where amylase is made

  • Salivary glands
  • Pancreas
  • Small intestine
• Proteins

  Found in things like nuts, meats and beans
• Breakdown of proteins

  Broken down by protease enzymes into amino acids
• Places where proteases are made

  • Stomach (pepsin)
  • Pancreas
  • Small intestine
• Fats/Lipids

  Found in foods like cheese, oils and chocolate
• Breakdown of fats/lipids

  Broken down by lipase enzymes into glycerol and fatty acids