Discussion questions are listed below. Each question is meant to be an independe

Question

Discussion questions are listed below. Each question is meant to be an independent thread. If you are the first to post on a particular question, please use the question number and title in your subject. Once a question has been started, please put your posts on that question within the existing thread.

Just do a description. It is supposed to be a dq!

1. Control Variables

Which control variables did you choose for these experiments? Reply to your classmates and discuss whether some of these are things that would be "coincidentally the same" versus ones that "you take deliberate action to keep the same."

2. Food Storage

Use the knowledge you gained in this lab to begin a discussion about how cooking foods or refrigerating them affects browning of vegetables, growth of bacteria/fungus, and spoiling or decomposing of food. Alternately, speculate on how the apples in a HappyMeal don't turn brown for days on end. What might they have done to them?

3. Other Enzymes

There are many other enzymes common to food and nutrition. Choose one you have heard of and do a little research. Propose an experiment with one of these, complete with all three types of variables named. Critique each other's experiments and suggest improvements. If you're really brave, run the experiment and report on the results. (Suggestions – Bromelain, meat tenderizer, Lactaid, lipase, Beano, etc.)

You must participate in at least one of the discussions. Make sure you post at least once by the first post date (check the schedule), that some of your posts are replies to other classmates, and that you post at least three times.

Explanation / Answer

3. Other Enzymes :

Investigating effect of temperature on the activity of lipase:

Lipase is an enzyme which converts fat to fatty acids and glycerol. This process occurs at physiological temperature in our body at 37°C. Lipase is an enzyme and as enzymatic activity varies with temperature we can detect the activity change with the temperature by a very simple experiment.

Reagents required:

Experiment:

·         Prepare lipase solution. Separate it into two parts in test tube. One put into ice bath another one into water bath with temp 37°C.

·         Add 5ml of milk into two separate test tube mark them and add few drops of phenolphthalein to both the test tube. Add 7ml of sodium carbonate solution to each tube. Mix well (The solution should be pink) and put one back to ice bath and another to water bath. Place a thermometer in the test tube.

·         Add 1ml of lipase to each of the tube and start time counting. Stir the contents of the test tube until the solution loses its pink colour

·         As soon as the solution became white stop time counting for each test tube.

Observation:

The time duration for test tube placed in water bath is much lesser than the test tube placed on ice bath.

Result and discussion:

Addition of Sodium carbonate solution makes the milk basic solution. Phenolphthalein is a pH indicator which colours pink in alkaline solutions of about pH10. When the pH drops below pH 8.3 it becomes colourless. Lipase converting fat to fatty acid helps to decreasing the pH level. More active lipase means quicker conversion rate from fat to fatty acid means lesser period needed for become the solution colour less. The tube in hat water bath took less time than the tube in ice bath means lipase works better at   37°C than 10°C.

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