1) What is the first step when you are testing for proteins?  a) Add Buriet solution to the sample b) Add Benedict’s solution to the sample c) Add Iodine solution to the dample d) Add Buiret reagent to the sample e) Add 0.5cm of sodium hydroxide and copper sulfate to a test tube 2) What would be the colour change if a solution tested positive for starch? a) Orange to brown b) Blue to black c) Orange to blue/black d) Blue to purple e) Orange and brown, blue and black 3) Why do you add sodium hydrogen carbonate to a sample when you are testing it if it contains a non-reducing sugar? a) To kill any microorganisms within the sample so it doesn’t affect the results b) To neutralise the acid from HCI c) The enzyme used to hydrolyse the glycosidic bonds in this test uses NaHCO3 to break down the polysaccharide into sugars d) All of them above 4) What test would you use for lactose? a) Benedict’s test for reducing sugars b) Benedict’s test for Non- reducing sugars c) Iodine test d) Lipids test 5) What test would you use for amylase? a) Lipids test b) Reducing sugars test c) Iodine test as amylase is found in starch d) Biuret test  6) What is the test for PABA and give a reason why? a) PABA is a test for starch as it stands for para-amylobenzoic acid so therefore it contains amylopectin which tests positive for starch b) It’s an acid so therefore you can’t test for any substances like carbs, proteins and lipids c) It contains amylopectin which isn’t a polysaccharide so therefore you would carry a Benedict’s test for reducing sugars d) PABA is a protein so this means you would need to perform the Biuret test. e) PABA is an enzyme so therefore you would need to perform the Buiret test. 7) Which one of these answers is the correct method for the lipids tests. a) First you would crush the sample and add ethanol and shake. Then add water and you will see a white/milky emulsion formed. b) First you crush and add ethanol then water and shake the solution. A white/cloudy emulsion will form. c) Crush the sample if its ONLY A SEED and then add water and shake the sample with ethanol. A positive result will show a white milky emulsion being formed. d) First you would only crush the sample if it’s a seed then add ethanol and shake. Then add water and a white milky emulsion is formed. 8) What type of lipids are usually found in foods? a) Phospholipids b) Triglycerides c) Glycerol and a fatty acid d) Glucose 9) Sample X doesn’t taste sweet. What test can you use to identify sample X ? a) A non reducing sugar test b) A reducing sugar test c) Non- reducing sugar test d) Iodine test 10) Which one of these answers is the correct method for the starch test? a) Add 2-3 drops of iodine solution to the sample and the sample will change colour to blue/black b) Add a drop of iodine from potassium iodide solution to the sample and the sample will turn blue/black. c) Add 2-3 drops of iodine from KI solution and the sample will turn blue/black. d) Add a couple of drops of iodine in potassium iodine solution and the sample will change COLOUR to blue/black e) Add 1-2 drops of iodine solution from KI2 (Iodine is a molecule so it has 2 after it) solution and the colour will change to blue/black f) All of them above

A level Biology Food Tests

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