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Biology 200 Spring 2014 Practice Exam 1: Biochemistry and Enzymology, Exams of Biology

Towson University (TU)Biology

A practice exam for biology 200, a course focused on biochemistry and enzymology. The exam covers various topics such as energy storage in cells, enzyme activity, substrate interactions, and protein synthesis. It includes multiple-choice questions, diagrams, and graphs to help students understand and practice the concepts. The exam is designed to simulate the experience of taking a biology 200 exam and may include questions on material not yet covered in the course.

Typology: Exams

2023/2024

Uploaded on 02/21/2024

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katherine-galvez-4 🇺🇸

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Biology 200, Spring 2014 Practice Exam 1
How to Use this Practice Exam:
I post practice exams to allow you to get a real sense of the experience of taking a Biology 200
exam. The best way to use each exam is as follows.
1. Do NOT answer the questions as a problem set.
2. Study material using your lecture and lab notes and do problem sets FIRST.
3. When you feel you are fairly prepared, put away all of your notes and sit down in a
quiet place where you will not be interrupted for at least an hour.
4. "Take" the exam without stopping to check notes or the book.
5. At the end of the exam, "grade" your responses. THEN go back and try and figure out
the ones you answered incorrectly. Use your notes/book if you need to at this point.
6. If you are still confused, contact an instructor or TA during their office hours or by email
so that you can get your questions answered.
NOTE: This exam may or may not reflect the content of the exam as presented this quarter,
nor will it necessarily be the same length (in fact, this one is WAY longer – I've added
several questions for your practice). Use these questions as a guideline as to the types of
questions that may appear on your exams. THEREFORE YOU MAY FIND QUESTIONS
ON MATERIAL WE HAVE NOT COVERED, OR THERE MAY BE MATERIAL NOT
EXAMINED IN THESE TESTS THAT YOU WILL BE RESPONSIBLE FOR.
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Download Biology 200 Spring 2014 Practice Exam 1: Biochemistry and Enzymology and more Exams Biology in PDF only on Docsity!

How to Use this Practice Exam:

I post practice exams to allow you to get a real sense of the experience of taking a Biology 200 exam. The best way to use each exam is as follows.

  1. Do NOT answer the questions as a problem set.
  2. Study material using your lecture and lab notes and do problem sets FIRST.
  3. When you feel you are fairly prepared, put away all of your notes and sit down in a quiet place where you will not be interrupted for at least an hour.
  4. "Take" the exam without stopping to check notes or the book.
  5. At the end of the exam, "grade" your responses. THEN go back and try and figure out the ones you answered incorrectly. Use your notes/book if you need to at this point.
  6. If you are still confused, contact an instructor or TA during their office hours or by email so that you can get your questions answered. NOTE: This exam may or may not reflect the content of the exam as presented this quarter, nor will it necessarily be the same length (in fact, this one is WAY longer – I've added several questions for your practice). Use these questions as a guideline as to the types of questions that may appear on your exams. THEREFORE YOU MAY FIND QUESTIONS ON MATERIAL WE HAVE NOT COVERED, OR THERE MAY BE MATERIAL NOT EXAMINED IN THESE TESTS THAT YOU WILL BE RESPONSIBLE FOR.

PRACTICE EXAM 1

Note: The codon table and the respiration intermediates are printed on the last 2 pages for your reference.

  1. Fill in the blanks: All questions refer to the four molecules diagrammed below: a) Molecule “A” fits best into which category of biological macromolecules? b) “B” fits best in which category of biological macromolecules? c) “C” fits best in which category of biological macromolecules? d) Which molecule would best be described as a fatty acid? ________ e) Which of these molecules could be a steroid hormone? ________ f) Which of these molecules has the most energy stored in the electrons in its bonds? _________ Multiple true/false – CIRCLE ALL THAT ARE CORRECT!
  2. Polyunsaturated oils… a) have no double bonds. b) are liquid at room temperature. c) cannot store energy that cells could use to make ATP. d) are more often found in animals than plants.
  3. A tRNA carrying the amino acid Arg (arginine)... a. may bind to the codon 5’ ACA 3’. b. can have the anticodon 5’ GCC 3’. c. will bind to the E site of a ribosome. d. can have the anticodon 3’ UCC 5’.

A

B

C

D

  1. The following graph shows the results of a student assay testing “mandase” enzyme activity in the presence of various concentrations of salt. Use these results to answer the questions below. a) At which salt concentration does mandase enzyme work the most effectively?

b) At what salt concentration is enzyme activity completely inhibited? _______ c) Which of the following interactions will most likely be affected first by addition of salt? (Circle one) hydrophobic interactions disulfide bonds ionic bonds d) The graph below shows the pathway of the reaction that mandase enzyme catalyzes in the presence of intact enzyme. Draw on the graph a reaction pathway in the absence of intact mandase.

  1. Fill in the blank. For each, write TWO different answers that fit the description given. (There may be more than 2 answers. Please write only TWO!) a. Catalyst that breaks a bond between i. __________________ ii. __________________ an amino acid and a tRNA. b. Anticodon for a tRNA that gets attached to i. __________________ ii. __________________ the amino acid ‘His’. (include 5’ and 3’ labels!) c. Something that is transcribed but is not i. __________________ ii. __________________ translated. G Progress of the reaction - >

7.As you saw in your problem sets, chemotrypsin is an enzyme which catalyzes the hydrolysis of peptide bonds. The first step of the reaction is shown to your right. Use this to answer the following questions. a) Describe briefly how an decrease in pH would affect the enzyme’s interaction with substrate ( not the enzyme’s structure.) (Answer in 1-2 sentences) b) Adding chemotrypsin speeds up this reaction by changing: (Circle all that apply) Δ G of the reaction Δ H of the reaction Δ G‡^ (EA) of the reaction G of the T.S.I. c) Draw a molecule in the space below that could act as a competitive inhibitor of chemotrypsin. d) In what organelle might you find an enzyme that performs a similar function to chemotrypsin?

e) Imagine that Gly-193 is changed to Alanine: Describe how you would expect the reaction to change (if at all) and why. (Answer in 1-2 sentences) substrate enzyme

  1. In studying a strain of yeast that is very sickly, you find that all of the enzymes in the cell are functioning poorly. a) In your first experiment, you sequence the genes for 7 enzymes involved in lipid metabolism. You find that they all have wild-type sequence. What can you rule out as a cause for this sick yeast? (Circle one) i) mutations in the DNA coding for lipid-metabolizing enzymes ii) mutations in the mRNA coding for lipid-metabolizing enzymes iii) mutations in the lipid-metabolizing enzymes’ primary amino acid sequences b) In your next experiment, you determine the amino acid sequence of each of the 7 proteins. In each one , the only difference you find is that the amino acid aspartic acid is sometimes found in the amino acid sequence when you should have a leucine. You conclude that this is not caused by an error of RNA polymerase during transcription. (RNA polymerase has an error rate of about 1 every 1,000 nucleotides.) How did you come to your conclusion? c) In a final experiment, you find a single mutation in a gene unrelated to lipid metabolism that accounts for the phenotype of this yeast strain. i. What does this gene code for? __________________________________ ii. How has its protein function changed? (Describe in 1-2 sentences)
  2. In organisms living on planet Mandoid, all of respiration is the same as on planet Earth except for one part: At every oxidation step of glycolysis, the linking step, and the Krebs cycle, FAD is the molecule that gets reduced. How many molecules ATP per molecule of glucose can a prokaryote living on planet Mandoid make? (Show all work for full credit.)
  1. On planet Rebus, the following reaction is catalyzed by a single enzyme as shown. Other than this reaction, the rest of respiration occurs just as it does on Earth. a. What does molecule “X” have to be to balance this reaction? _________________ b. What is the total number of ATP that can be made from a molecule of glucose in a eukaryote on planet Rebus? (Assume there is oxygen on Rebus and that there is an NADH FADH 2 shuttle. Show all work for full credit.)
  2. Imagine a eukaryotic cell in which there is a mutation in both copies of the gene for ATP synthase. In this mutant, the ATP synthase is not as efficient, requiring twice as many H+ to pass through to make a single ATP molecule compared to normal, wild type cells. How many ATP can the mutant organism make per glucose molecule? (Normal cells make ~30 ATP/glucose)
    • ATP from Substrate-level phosphorylation: _______
    • ATP from Oxidative phosphorylation: _______

“X”

  1. This is the same reaction mechanism as the one you saw in Quiz 2. The complete reaction mechanism is shown. NEW INFORMATION: This enzyme is composed of a single polypeptide and is found in humans. a. If this enzyme were treated with high salt concentrations, which levels of protein structure would be disrupted? (Circle ALL that apply) 1° 2° 3° 4° b. If this enzyme were treated with high salt concentrations, which types of bonds would be disrupted? (Circle ALL that apply) peptide disulfide H-bonds ionic bonds bonds bonds c. Which of the following is TRUE? (Circle ALL)
  • G of the reactants > G of the products
  • EA of the reaction with enzyme > EA without enzyme
  • ΔG of the reaction is positive
  • G of enzyme at beginning > G of enzyme at end d. Which of the following molecules would be the BEST competitive inhibitor of this enzyme? (Circle ONE) e. If Gly26 were changed to the amino acid shown below, would the reaction rate increase, decrease, or stay the same? Give one specific reason using a few words. f. Bacteria that live at 100°C in hot springs have an enzyme that carries out the same reaction. How would you expect the enzyme structure to be different?

Step 1

Step 2

B

A

Asp Asp His Asp Gly

  1. Fill in the blanks: a. Where is ATP synthase in a eukaryotic cell? (Be specific!) ________________________ b. You have 1 gram of glucose, 1 gram of protein, and 1 gram of fat. Which has the most energy that cells can use to make ATP? __________________ c.Name one way you could change a lipid bilayer to make it less permeable. ____________________________________ d. In a membrane protein, what is the characteristic of the R-groups that come in contact with the interior of the phospholipid bilayer? ____________________ e. Name one molecule that is permeable through a lipid bilayer: ________________________
  2. On planet Spensoid, organisms primarily use the carbohydrate "erythrose" as an energy source for respiration. Eukaryotic cells on Spensoid have enzymes that carry out the following reactions: a. How many pairs of high energy electrons does erythrose have? ________ b. Should any of the reactions in the diagram shown above have NAD+ as a substrate as well? Explain your answer in a few words. c. Starting with one molecule of erythrose, fill in the table below with the number of each molecule produced in a eukaryotic cell on Spensoid. Assume that all Earth enzymes are present and that Spensoid organisms have an NADH-> FADH 2 shuttle. (Respiration diagram shown on p. 1). ATP from substrate level phosphorylation

NADH FADH 2 CO 2

Glycolysis Linking Step/ Krebs Cycle

2 HSCoA

erythrose

2 H 2 O

FOR YOUR REFERENCE ONLY. NOTHING WILL BE GRADED ON THIS PAGE.

Codon Table

FOR REFERENCE ONLY:

The number next to each

intermediate represents the total

of C-C and C-H bonds in that

molecule.