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BIOL 1208 Chapter : Writing Assignment 2

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azuremammoth471
15 Mar 2019
School
LSU
Department
Biological Sciences
Course
BIOL 1208
Professor
All

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Document Summary

In this experiment, the independent variables were the time elapsed and the type. The dependent variables in the experiment were the concentration and the rate of enzymatic reaction. When the procedure was complete, the results showed that the catechol had the highest concentration and the largest rate of enzymatic reaction. Resorcinol had the next highest and the hydroquinone has the smallest concentration and rate of enzymatic reaction. It should be noted that the results of the experiment were contaminated. The bottle of resorcinol was contaminated by trace amounts of catechol which affected the rate of enzymatic reaction for the resorcinol sample. The results of the experiment show that the catechol had the fastest rate of enzymatic reaction. The experiment revealed that changing the substrate used in a solution changes the rate of enzymatic reaction. The alternative hypothesis stated that the rate of enzymatic reaction would change if the type of substrate was changed.

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Related Questions

Enzymes Lab Report

  1. Enzyme Structure and Function

  1. Define the following:

  1. enzyme
  1. substrate
  1. Explain how enzymes function.

  1. Go to Lab, Section I, Exercise 1 to participate in an activitythat demonstrates the importance of enzymes. Record the colorintensity of the solution in each test tube at five and tenminutes.

Time

(min)

Tube S1

Potato Extract + Catechol

Tube S2

Potato Extract + Water

Tube S3

Catechol + Water

0

5

10

  1. How can benzoquinone be detected?
  1. Why were potatoes used in the experiment?

  1. Enzyme Specificity

  1. Based on Section II, Exercise 2, as determined by colorintensity, to what extent does catechol oxidase react withhydroquinone?
  1. What was the role of hydroquinone in the experiment?

  1. Temperature and Enzyme Activity

  1. Based on Lab, Section III, Exercise 3 record the relative colorintensity at five-minute intervals to determine the temperaturerange for catechol oxidase.

Time

(min)

Tube 1

4oC

Tube 2

23oC

Tube 3

40oC

Tube 4

60oC

Tube 5

80oC

Tube 6

100oC

0

5

10

  1. Construct a bar graph of the data for the ten-minute readings.Label axes and provide units. Sign, date and prepare an image ofyour graph and include it with this lab report.

  1. What is the optimal temperature range for catechol oxidaseactivity?

  1. pH and Enzyme Activity
  1. Within what pH range will catechol oxidase catalyze catecholand oxygen to form benzoquinone?
  1. Define pH.
  1. What is the role of catechol in the experiment?
  1. Which test tube contains the most acidic buffer solution?
  1. Cofactors and Enzyme Activity

  1. What is a cofactor?

  1. What cofactor is necessary for catechol oxidase activity?

Summary Questions

  1. What was the role of catechol oxidase in the experiments?

  1. What was the purpose of developing a color intensityscale?

  1. Identify three factors that influence the rate of enzymaticreactions.
  1. Examine the data in Exercise 3 and suggest a hypothesisexplaining why people with a fever feel tired and listless.

  1. People who have been suddenly submerged in cold water andremained for long periods of time have survived. Examine the datain Exercise 3 and explain how this is possible.

  1. How does pH range affect the function and structure of catecholoxidase?

  1. The stomach maintains a pH of approximately 3 to 5. Do allenzymes function at this pH level? Examine the data in Exercise 4and determine if catechol oxidase would function in the stomach.

  1. What is enzyme specificity? Give an example.

how would an error in preparing a spectrophotometer blankexplain an upside-down absorbance trend?

in a lab analzying the effect of temperature and pH onenzyme-catalyzed reaction rate, we used a spec 20 to measureabsorbance of potato-extract (containing catacholase aka potatopolyphenol oxidase) and added subtrate (catechol) -- the reactionforms benzoquinone, which is visible in browning. Absorbance wasmeasured after 5 minutes in 4 different temperature solutions(4deg, 25deg, 37deg, 65deg -- C). Expected absorbance peak wouldhave been room temp 25deg, low would have been 65deg (re: enzymesare proteins, proteins denatured at higher temps). Instead we hadabsorbance PEAK at 65deg, LOW at 25deg. I did not prepare orobserve the preparation of the blank or the calibration of the spec20 or the preparation of the potato extract itself (this was a4-person, 4-part lab and I was working on a ph-dependent relatedexperiment while the extract and blanks were created).

What kind of error would explain these results that appear to beexactly opposite of the expected trends? Incorrect blank? Improperratios or temperature in potato extract (theoretically made from aroughly 2:1 volume ratio of cold water to peeled potato, blended,strained over a beaker in ice and spun at 2000rpm for 2 min, andthen kept in tubes over ice until the start of the experiment)?

Any (and as detailed as possible) suggestions would be greatlyappreciated. I have a lab report due on this, the data makes nosense, and my lab partners are oblivious.

Temperature (C) Absorbance
4 0.469
25 0.436
37 0.474
65

0.493

I need a good introduction and conlcusion of this experiment below is the expermeint and my results.

In this experiment you will observe the action of the enzyme amylase on starch. Amylase changes starch into a simpler form: the sugar maltose, which is soluble in water. Amylase is present in our saliva, and begins to act on the starch in our food while still in the mouth.

Exposure to heat or extreme pH (acid or base) will denature proteins. Enzymes, including amylase, are proteins. If denatured, an enzyme can no longer act as a catalyst for the reaction.

Benedict's solution is a test reagent that reacts positively with simple reducing sugars like maltose, but will not react with starch. A positive test is observed as the formation of a brownish-red cuprous oxide precipitate. A weaker positive test will be yellow to orange

PRE-LAB:

Add 1g of cornstarch to a beaker containing 100ml of cold distilled water. While stirring frequently, heat the mixture just until it begins to boil. Allow to cool.

PROCEDURE:

1. Fill the 250-mL beaker about 3/4 full of water and place on the hot plate for a boiling water bath. Keep the water JUST AT BOILING.

2. Mark 3 test tubes A, B and C. "Spit" between 1 and 2 mL of saliva into each test tube.

3. Into tube A, add 2 mL of vinegar. Into tubes B and C, add 2 mL of distilled water. Thump the tubes to mix.

4. Place tube B into the boiling water bath for 5 minutes. After the five minutes, remove from the bath, and place back into the test tube rack.

5. Add 5 mL of the starch solution to each tube and thump to mix. Allow the tubes to sit for 10 minutes, occasionally thumping the tubes to mix.

6. Add 5 mL of Benedict's solution to each tube and thump to mix. Place the tubes in the hot water bath. The reaction takes several minutes to begin.

OBSERVATIONS:

Tube A: Starch + saliva treated with vinegar (acid)

Was the test positive or negative? Negative

What does this indicate? The vinegar stops the action of amylase from catalyzing the starch therefore the solution becomes cloudier. This indicates that vinegar (acids) distort the shape of proteins in the salivary amylase.

Results: The solution turns cloudy.

Conclusion: Acids denature the shape of proteins in the salivary


Tube B: Starch + saliva and water, treated in a boiling water bath

Was the test positive or negative? Negative

What does this indicate? It indicates that when enzymes are exposed to extreme temperature for some time they are denatured and therefore become inactive.

Results: The benedict’s solution retained its color as the reaction did not occur. Extreme temperatures denatures enzymes, therefore when the salivary amylase was introduced to a hot water bath for five minutes the amylase was denture.

Conclusion: Salivary amylase/enzymes when introduced to hot temperatures it is a denatured therefore does not react on the substrate.


Tube C: Starch + saliva

Was the test positive or negative? Positive

What does this indicate? This indicates that the salivary amylase successfully worked on the starch.

Results: The benedict’s solution turned brown as an indication of the presence of sugar.

Conclusions: Salivary amylase acts on starch in favorable conditions, ie is optimum te

Please provide a lab report that explains your procedure, results and conclusions. Remember to include pictures of the lab set-up and results. Also, I want you to expand this initial experiment by proposing and testing (in the form of an additional experiment) a testable hypothesis that involves the above general concept. You will be graded on your use of the scientific method and the creativity/complexity of your experiment. Both the above experimentation and your original experiment may be included together into one experiment