Topics: Starch, Enzyme, Digestion Pages: 6 (1844 words) Published: April 19, 2013
Investigating Enzyme activity
Fresh watermelon is a great way to increase the amount of enzymes in your diet, the type of enzymes watermelons have are digestive enzymes. Digestive enzymes are enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption by the body, (Thomas A Brown, 2013).

Enzymes are catalysts (most are proteins) that speed up chemical reactions in the cell. The purpose of an enzyme in a cell is to allow the cell to carry out chemical reactions very quickly. These reactions allow the cell to build things or take things apart as needed (Marshall Brian, Unknown) Enzymes have very specific jobs, they can only work with specific molecules and only do specific tasks. An enzyme works by binding to specific molecules called reactants or substrates.

An example of an enzyme at work is Amylase. Amylase is an enzyme that helps digest carbohydrates. It is produced in the pancreas and the glands that make saliva. When the pancreas is diseased or inflamed, amylase releases into the blood. Pancreatic amylase goes into action after the partially digested food is emptied into the small intestine and the pH returns to the neutral range. Starches continue to be broken into smaller trisaccharides and disaccharides and possibly even into glucose for energy. (Edward Group, 2012)

To investigate the breakdown of complex molecules into simpler molecules and to investigate enzyme activity and what factors effect enzymes.

* Thermometer (10-1100C)
* Benedict’s Solution
* Iodine (iodine/potassium iodide) stain solution
* Distilled water
* 250mL beaker
* Four large test tubes
* Test-tube rack
* Test-tube holder
* Two 50mL measuring cylinders
* Two pieces of dialysis tubing (20cm)
* Four rubber bands
* Marking pen
* 1% starch solution
* 1% diastase enzyme solution
* Bunsen burner, tripod and gauze mat
* Spotting tile

Safety Check:
1. Before setting up your bunsen burner make sure you know how to set up and turn it on properly and make sure you have the supervisors permission to use it. 2. When heating a test tube with a bunsen burner turn the open side of the test tube towards a wall or where there isn’t anything or anyone that can be damaged. 3. Wear safety glasses at all times when around chemicals or a flame. 4. Inspect all equipment before you use it and test that they are in full working order.

1. Set up your Bunsen burner.
2. Three-quarters fill the 250mL beaker with water at around 200C. 3. If the water is below 200C Then setup your tripod and gauze mat over the bunsen burner and heat it up gently, but not over 250C. 4. Pour 1cm of diastase enzyme solution into a clean test tube. 5. Add 4 drops of benedict’s solution and heat it up gently in the bunsen burner flame. 6. Record the result of this test (there was no colour change, only a few bubbles – no reaction). 7. Take a piece of dialysis tube and wet it with water.

8. Tie a knot in one end and repeat with another piece of dialysis tubing. 9. Label large test tubes A and B.
10. Half fill one dialysis tubing with starch solution.
11. Tie the open end of the bag with a rubber band.
12. Wash the outside of the tubing to remove any starch from the outside. 13. Place the bag in the large test tube and tie the bag to the inside of the large test tube with a rubber band. 14. Carefully fill the test tube with distilled water.

15. Let test tube A stand in the beaker with 200C water for approximately 30 minutes. 16. Repeat steps 9 to 13 with the other dialysis tubing and large test tube B but this time fill the dialysis tubing with 3 ml of Diastase solution then add starch solution until the bag is as full as the one in test tube A. 17. Let test tube B stand in the beaker with 20 degrees Celsius water for approximately 30 minutes....
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