SB1

• what do protease convert proteins into?

  amino acids
• what do carbohydrase convert carbohydrates into?

  simple sugars
• what is the function of a digestive enzyme?

  breaks down big molecules to make them smaller and soluble
• how does substrate concentration affect the reaction?

  the higher the concentration, the faster the reaction
• what will happen if the substrate’s shape doesn’t match the active site’s shape?

  the reaction won’t be catalysed
• what is a substrate?

  the molecule that has changed in the reaction
• what are the purposes of enzymes?

  reduces the need for high temperatures. they speed up useful chemical reactions in the body
• what is the equation for total magnification?

  eyepiece lens magnification X objective lens magnification
• what does Benedict’s reagent test for?

  sugars
• what does the Biuret test test for?

  proteins
• what solution is used to test for starch?

  iodine
• what do lipases convert lipids into?

  glycerol and fatty acids
• what is an active site?

  the part where it joins on its substrate to catalyse the reaction
• what is active transport?

  movement of particles across a membrane, from low to high concentration using energy transferred from respiration
• what is osmosis?

  movement of water across a semi permeable membrane from high to low water concentration
• what is diffusion?

  movement of particles from high to low concentration
• what is the difference between prokaryote and eukaryote cells?

  prokaryotes: single celled organisms

  eukaryotes: multicellular organisms
• where are the nutrients in the egg cell to feed the embryo?

  cytoplasm
• why do sperm cells have a lot of mitochondria?

  to provide energy (from respiration) to swim the distance
• when using a microscope, what is the purpose of stain?

  to make transparent/colourless specimens easier to see by highlighting different structures within cells
• when were light microscopes invented?

  1590s
• what do light microscopes allow you to see?

  nuclei and chloroplasts, they are used to study living cells
• when were electron microscopes invented?

  1930s
• what do electron microscopes allow you to see?

  internal structures of mitochondria and chloroplast, they are used to study how cells work and the role of subcellular structures
• what is the ‘lock and key’ mechanism?

  for the enzyme to work, the substrate has to fit into the active site, if it doesn’t match, the reaction won’t be catalysed
• how many substrates do enzymes usually work with?

  one substrate, they are said to have high specifity for their substrate
• what happens if an enzyme-catalysed reaction gets too hot?

  some of the bonds holding the enzymes together break. This changes the shape of the enzyme’s active site so the substrate won’t fit. The enzyme is denatured.
• what other factors affect the nature of enzymes?

  pH, if the pH is too high/low it interferes with bonds holding the enzyme together
• what does the Emulsion Test test for?

  lipids
• which liquid is added to the test substance when testing for lipids?

  ethanol, shake the test substance with ethanol for about a minute until it dissolves, then pour the solution into water
• what will happen in the Emulsion Test if lipids are present?

  lipids will precipitate out of the liquid and show up as a milky emulsion
• what is an emulsion?

  when one liquid doesn’t dissolve in another, it just forms little droplets
• what do amylase convert starch into?

  maltose
• when using iodine, what colour does the solution turn when starch is present?

  brown/orange to blue/black
• what is the equation for the rate of reaction?

  rate = 1000 / time
• what happens inside plants when they need energy?

  plants store energy in the form of starch. Enzymes break down the starch into smaller molecules (sugars), these can be respired to transfer energy to be used by cells
• how are carbohydrates synthesised?

  by joining together simple sugars
• how are proteins synthesised?

  by joining together amino acids
• how are lipids synthesised?

  by joining glycerol and fatty acids
• what is glycogen synthase?

  an enzyme that joins together lots of chains of glucose molecules to make glycogen