Lab Protocol Day 2 - Alien Profile Story
Scenario: There has been an alien crash landing. You are a scientific investigator in a secret department of the CIA. During the night a U.F.O has crashed to the ground. An injured unknown organism was found in the crashed wreckage. Organism identification books were also found in the wreckage. In order to save the organism’s life you must identify it by using chemical indicator tests. Based on the size of the aircraft and the alien, scientists have narrowed it down to three possible species. Using your knowledge of indicators, the identification guide and the alien profiles below, determine which alien was found in the wreckage by performing a saliva pH test, a protein urine analysis, a blood glucose test, and a starch analysis of sweat.
Species A is known to consume high concentrations of starch and has acidic saliva. Species A’s diet is low in protein and lacks the enzyme for the breakdown of starch into glucose.
Species B is known to consume high concentrations of glucose and has neutral saliva. Species B lacks the ability to store their excess glucose into starch. Their cell membranes lack the ability to absorb protein.
Species C is known to consume low concentrations of glucose and high concentrations of protein. There is no starch found in their cells. Species C has basic saliva.
Material Needed Per Group:
Safety goggles, lab apron, and gloves for each student
1 Test tube rack containing 4 test tubes containing and labeled with alien specimens
1 Hot water bath in safe location for all student group use
1 dropper bottle of iodine solution
1 dropper bottle of red cabbage juice indicator
1 dropper bottle of biuret reagent
1 dropper bottle of Benedict solution
1 Data Sheet for recording laboratory results
Procedures for starch indicator test:
Add 5 drops of iodine to the test tube labeled “Sweat.” Swirl to mix.
Record the immediate color change for test tube on Data Sheet. Determine if the alien’s sweat is positive or negative for starch.
Procedures for glucose indicator test:
Add enough Benedict solution to the test tube labeled “Blood” until the solution is blue in color.
Place test tube into a hot water bath for 2 minutes and record any resulting color change on the Day 2 Data Sheet. Determine if the alien’s blood is positive or negative for glucose.
Procedures for protein indicator test:
Add 5 mL of biuret reagent to the test tube labeled “Urine.”
(CAUTION) Be careful not to spill biuret solution on your skin or clothing. If a spill occurs, rinse with plenty of water.
Seal test tube with a rubber stopper or a screw top lid and shake for 10 seconds. Observe and record any color change on the lab data sheet. Determine if the alien’s urine is positive or negative for protein.
Procedures for pH test using red cabbage juice indicator:
Add 10 drops of red cabbage juice indicator to saliva test tube. Swirl to mix. Use the pH indicator strip to determine the pH number of alien’s saliva and record pH information on data chart.