topic B1-cell structure

• A catalyst is a substance that increases the speed of a chemical reaction without being used up or changed in the process.
• what effects enzymes?

  temperature,ph,concentration
• Explain how increasing the temperature can cause an enzyme to denature.

  break bonds of the enzyme and it'll cause the active site to change shape so it wont be complementary to the substrate
• biological molecules-carbs, protein, lipids
• carbohydrates are broken down by amylase which forms glucose made in pancreas and small intestines
• proteins are broken down by protease and converted to amino acids
• lipids are broken down by lipases and converted to fatty acids and glycerol
• benedicts test is for reducing sugars
• benedicts test -put benedicts solution in a test tube and place in water bath for 5 mins and if it turns brick red then it has reducing sugars but if not it will remain blue
• iodine test-put iodine solution in a test tube, and it will go form orange to blue/black when shaken
• biuret test-put solution in test tube which is blue and add potassium hydroxide and copeer sulphate which will change to pink/purple
• emusion test- add ethanol in test tube and shake, add water and if it turns cloudy white,there are lipids present
• diffusion

  movement from a high concentration to low concentration
• 3 factors that affect diffusion

  The higher the concentration gradient, the higher the rate of diffusion

  Higher temperature = higher rate of diffusion

  The larger the surface area, the faster the rate of diffusion
• osmosis

  water particles moving from a high to low concentration
• Active transport is the movement of molecules across a membrane, from a region of low concentration to a region of highconcentration. This requires energy from respiration.