Chemistry of Life LAB PDF

Preview

Summary

E-Science Lab...

Description

The Chemistry of Life PRE-LAB QUESTIONS 1. Nitrogen fixation is a natural process by which inert or unreactive forms of nitrogen are transformed into usable nitrogen. Why is this process important to life? Many plants need nitrogen to help them grow and thrive. Nitrogen fixations provide the nitrogen in the soil, which then gets received by the plants. The process is important to life because without it, many living organisms would not receive the nitrogen they need to survive. 2. Given what you have learned about the hydrogen bonding shared between nucleic acids in DNA, which pair is more stable under increasing heat: adenine and thymine, or cytosine and guanine? Explain why. Cytosine and guanine are more stable under increasingly heated conditions because the more hydrogen bonds there are, the more stable the nucleotides will be. Cytosine and guanine have 3, while adenine and thymine only have 2. 3. Which of the following is not an organic molecule: methane (CH 4), fructose (C6H12O6), rosane (C20H36), or ammonia (NH3)? How do you know? Ammonia, I know this because organic molecules are supposed to be carbon-based, ammonia is the only option that does not contain Carbon.

© eScience Labs, 2018

The Chemistry of Life EXPERIMENT 1: TESTING FOR PROTEINS Data Tables Table 1: Testing for Proteins Results Sample 1. Albumin Solution 2. Gelatin Solution 3. Glucose 4. Water 5. Unknown

Initial Color

Final Color

Is Protein Present?

Clear/ white-ish

Purple

Yes

Light yellow

Purple

Yes

Clear

Light blue

No

Clear

Light blue

No

Cloudy white

White

No

Post-Lab Questions 1. Record your hypothesis about what will happen when Biuret solution is mixed with the solutions from test tubes 1, 2, 3, and 4 here. Be sure to use scientific reasoning to support your hypothesis. I think the albumin, gelatin, and the unknown solutions will have protein in them because they all have a similar initial color. I do not think that the water and glucose will end up containing protein. 2. Write a statement to explain the molecular composition of the unknown solution based on the results obtained during testing with the Biuret solution and each sample solution. After looking over my results, it is clear to me that the unknown solution is, it does not contain protein. I know this because the biuret solution is supposed to reveal the solutions with protein in them and the unknow solution had a different and otherwise subtle reaction. 3. Diet and nutrition are closely linked to the study of biomolecules. How should you monitor your food intake to ensure the cells in your body have the materials necessary to © eScience Labs, 2018

The Chemistry of Life function? If you pay attention to the ingredients that are in the foods you are consuming, you can ensure that you will get the necessary nutrients you need. 4. There are other types of reagents used to determine what type of biomolecule a substance is. For example, copper ions present in Benedict’s reagent reacts with the free end of any reducing sugars, such as glucose, when heated. Originally blue in color, these copper ions are reduced by the sugar, and produce an orange-red colored precipitate. Alternatively, iodine-potassium iodide (IKI) may also be used when working with starch. IKI contains special tri-iodine ions which interact with the coiled structure of a starch polymer. Prior to a reaction, the IKI displays a yellow-brown color; however, after reacting with starch, a dark purple or black color is presented. The molecule pictured below produced a blue color when tested with Benedict’s reagent, a yellow color when tested with IKI, and a violet color when tested with Biuret reagent. Based on the structure shown below and these chemical results, what kind of biomolecule is this? The molecule is a protein biomolecule, not only did the substance turn purple when it was mixed with biuret (indicates protein), but also the model looks identical to a protein biomolecular model.

© eScience Labs, 2018

The Chemistry of Life

© eScience Labs, 2018...