Testing for nutrients and Enzyme activity

1. Testing for nutrients and Enzyme activity LaGuardia Community College Lab #3 Prof. Santos

2. Lab 4; Assignment 4 • To test for carbohydrates, lipids, and proteins.

3. carbohydrates • Monosaccharide- one sugar • Disaccharide- 2 sugars joined together by dehydration synthesis • Polysaccharide- many simple sugars joined by dehydration synthesis

4. Testing for reducing sugars • Use benedict reagent. A blue solution that will turn color in the presence of sugars. Example; glucose • Greenish- a small amount of sugar present • Orange- a large amount of sugar present • You have to heat the mixture of sample and benedict reagent!

6. Testing for starch • Starch is a polysaccharide found in plants. It is a major source of energy. The enzyme amylase in our saliva begins the breakdown of starch in the food we eat. Pasta and bread have plenty of starch! • Use Iodine, an amber colored solution, to test for starch. • Positive- blue/black color

8. Testing for proteins • Proteins are made up of amino acids. Proteins have many functions in our body. Our body can also use proteins for energy. • To test for proteins, use Biuret reagent! • ****be careful with the Biuret reagent! • Biuret is an aqua colored solution. It contains sodium hydroxide and copper sulfate. In the presence of proteins, it will change to a purple color!

10. lipids • Lipids are organic compounds that are insoluble in water. They include fat, oils, waxes, and phospholipids. • Fats are triglycerides composed of a glycerol and 3 fatty acids joined together by dehydration synthesis. • Fats are a source of stored energy and insulation.

11. Testing for fats • 2 ways! 1- using a brown paper bag to detect the presence of a translucent spot. 2- Sudan IV, a solution that will stain lipids red!

13. Lab #5 Enzymes • Enzymes are biological catalysts that speed up the rate of chemical reactions. • They lower the activation energy of a chemical reaction and thus make the reaction go faster! • Enzymes are highly specific and only work on a certain substance called the substrate. • Enzymes have a specific shape that allows them to work on specific substrates.

14. The part of the enzyme where the substrate fits in the active site!

15. catalase • Breaks down hydrogen peroxide into water and oxygen. • Found in liver, beef, turnips, apples, onions and potatoes. • A very fast enzyme, can break down 40,000,000 molecules of hydrogen peroxide per second! • Do assignments 1, 2, and either 3 or 4!

16. Factors that affect enzyme activity! 1- temperature 2- pH 3- enzyme concentration 4- substrate concentration

17. temperature