BIOS 2011 Lab 1 Enzymes

The time it takes to reach this lack of reaction with

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: he amylose forms a tight helix around I5 ­ ions (a string of five iodine atoms with a minus one charge), which turns the test solution opaque blue ­black. During each trial of a ­Amylase digesting starch you will pipette off small amounts of liquid from the reaction test tube to a spot plate with IKI, to see if starch is still present. As the starch begins to disappear, later tests will no longer change blue ­black with the indicator but will be dark brown, then a lighter red ­brown, showing the digestion of the starch has progressed to smaller dextrins, shorter polymers of glucose. At the end of the reaction, the test results will show no reaction with the indicator, which will remain a light yellow. The time it takes to reach this lack of reaction with the indicator, when all the starch has been hydrolyzed to maltose and maltotriose, is the endpoint time you will record. You will then calculate rate by dividing the amount of starch hydrolyzed by the endpoint time. 5 Exercise 1 Enzymes PROTOCOL 1: THE INHIBITION OF SUCCINIC DEHYDROGENASE BY MALONIC ACID 1. Label 6 small test tubes with numbers 1 ­6 using a Sharpie or other lab marker. 2. Refer to the table below for the volumes of reagents to be added to each tube. Using micropipetters add the all the listed reagents to the 6 tubes, except the Calf heart. Calf heart should be added last. Tube Succinic Acid Methylen e Blue Deionize d H2O Other Calf Heart 1 90 µL 210 µL 270 µL 500 µL Sucrose 0 µL 2 90 µL 0 µL 480 µL — 500 µL 3 0 µL 210 µL 360 µL — 500 µL 4 90 µL 210 µL 270 µL — 500 µL 5 90 µL 210 µL 240 µL 30 µL Malonic acid 500 µL 6 330 µL 210 µL 0 µL 30 µL Malonic acid 500 µL 3. Add the Calf heart to the tubes and mix vigorously by Pasteur pipette, or use a vortex mixer if you prefer. Note that Tube 1 has no Calf heart, but uses plain Sucrose instead. If you have measured all reagents and the deionized water correctly the tubes should all have the same total volume of liquid, and the menisci should be at the same height in all tubes. 4. Patiently and slowly pipette 250µl mineral oil into each tube to form a continuous layer 1 ­2 mm (or c. 1/16”) thick on the surface above the reactants. Mineral oil is very viscous and must be pipetted more slowly than aqueous solutions. This will keep oxygen from entering the reaction to re ­oxidize any Methylene White. 5. Make a note of the initial color in each tube in the worksheet below. Place your rack of small test tubes into the 37°C water bath nearest your bench. Incubate for 1 hou...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern