Biological molecules & enzymes

• Diffusion is the net movement of particles from a higher concentration gradient to a lower concentration gradient.
• Osmosis is the net movement of water molecules from a higher water potential region to a lower water potential region, through a partially permeable membrane.
• Active transport is the movement of molecules from a lower concentration region to a higher concentration region, against the concentration gradient, using energy from respiration.
• Glucose and maltose are simple sugars (soluble, can’t be stored); polysaccharide is a complex sugar (insoluble chains for storage)
• Proteins are made of chains of amino acids
• Lipids (fats) are solid in room temperature.
• Lipids are triglycerides, which is made of 1 glycerol molecule and 3 fatty acids
• Enzymes are biological catalysts that speeds up the rate of reaction in living organisms and it is unchanged/can be used again.
• Successful collisions means substrate has bound to the enzymes active site, forming an enzyme-substrate complex
• The more successful collisions = more products made
• The active site of the enzyme is complementary to the substrate.
• If the temperature is past the optimum temperature of the enzyme, the enzyme will be denatured, which means the bonds in amino acids in the active site breaks. So the substrate cannot fit into the active site.
• If the pH is too high or too low, the enzyme will be denatured too.
• What do enzymes do?

  Lowers energy needed for respiration.
• Iodine tests for starch. Positive results : blue black colour
• Benedict’s solution tests for reducing sugar or glucose. Heat in water bath at 80°C for 5 mins, colour change from blue to red
• DCPIP solution tests for Vitamin C. Positive result: the Blue solution decolourises
• Ethanol and water (emulsion test) tests for lipids. Positive result: cloudy emulsion After shaking the tube
• Biuret’s solution tests for protein. Positive result: blue to violet
• Carbohydrates and Lipids are made of CHO
• Protein is made of CHON + random