purpose: Finding positive indicator tests for proteins, carbohydrates, and fats, as well as finding parts of eggs that test positive for proteins, carbohydrates , and fats.
materials: eggs, beaker 250 mL, white vinegar, plastic wrap, slotted spoon, sodium chloride, distilled water, beaker 100 mL, pipets 5 mL, green pipet pump,glass tubes 13x100 mm, peg racks for 13x100 mm tubes, glucose, benedict's solution, hot plate stirrer, test tube holder, soluble starch, lugol's iodine solution, vortex mixer, gelatin, sodium hydroxide, cupric sulfate 5-hydrate, oil, sudan IV solution, scalpel handles #4, scalpel blades #22 for #4 handles, plastic trays
Procedure
part 1: Separating cell structures
1. Put an uncooked egg into a beaker of white vinegar. Label it and then cover it with plastic wrap. Let it sit for 24-48 hours and the shell should begin to dissolve. As it dissolves, start on procedure part 2.
2. When the 24-48 hours is up gently pick up the egg with the slotted spoon and rinse in water. What chemicals were involved as reactants and products?
3. Feel the outer membranes of the cell. This provides a good model of the cell membrane. Place egg in beaker of 5% NaCl solution for 24 hours. Describe appearance of egg. What may have caused the change in appearance?
4. Gently rinse egg in water. Then place egg in beaker of distilled water for 24 hours. Describe the appearance of egg after 24 hours. What caused the change in appearance?
5. To retrieve the egg cell, gently slice open egg's membranes. Let egg white drip through the slotted spoon into 100 mL beaker. Don't pierce yolk.
6. place egg yolk into another beaker, and set aside the egg membranes.
part 2: testing standard solutions
test four solutions of known composition (positive controls or standards) with their respective indicator solution. The standards show what a positive test should look like monosaccharides, starch, proteins, or lipids.
standard (molecule tested) |
indicator used |
describe positive control (standard) test results |
description negative control test results |
glucose
starch
protein
fat
|
benedict's solution
Lugol's iodine
Biuret reagent
sudan IV
|
1:00 blue 1:30 yellow 2:20 brown
instant change: brown
instant change lavender
instant change pink near bottom
|
no color change
amber
clear
clear with pink tint
|
part 3: Molecular Composition of Egg Components
1. Do each indicator test but change each egg components to be tested for sugar, starch, protein, and fats. All variables from part 2 should be the same, only the unknowns should be changed.
2. Record all the results for egg membrane, yolk, and egg whites for all four molecules.
3. give a number value for each to test and record into data table and remember to have short description of color change.
egg_table.gdoc | |
File Size: | 0 kb |
File Type: | gdoc |
Reflection
This lab was very interesting and a great way to get to know many different lab materials, such as pipet fillers, slotted spoon, vertex and hot plates are just a few of the items I was introduced to for the first time. My favorite part of this lab was going in everyday and seeing how the egg in the vinegar changed. My partners during this lab were Matt and Robert. We worked well together and developed a system, but at times we didn't agree on how to divide the work evenly. If we were to do this again I would definitely want to be more hands on, my job really was just putting the materials in the boiling water and timing the change. I also would have liked to take more organized notes instead of messy jots on my paper. Overall this lab was very fun and interesting.