BCH5413 Exam 1 QUESTIONS WITH ANSWERS

BCH5413 Exam 1 QUESTIONS WITH |\ |\ |\ |\ |\




ANSWERS


1. In the experiment described that supports DNA as the genetic
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material:


a. |\




Why does the mouse die if the researcher mixes the completely
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dead pathogenic strain with live non-pathogenic strain bacteria
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and then injects it into the mouse? (The first mouse in the
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figure). - CORRECT ANSWERS ✔✔- R strain has been transformed
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= now S strain
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---- can produce virulence factors that make the S strain deadly
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to mice. |\ |\




-- pathogenic strain is killed, its DNA is released, and now floating
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freely can go into the R strain and TRANSFORM it.
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1. In the experiment described that supports DNA as the genetic
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material:


b.
What was the only scenario in which the mouse lives? Why? -
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CORRECT ANSWERS ✔✔-- When DNA of the S strain was |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


destroyed

,-- DNA that caused the virulence factors is destroyed = no
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function


2. What were the contributions of Wilkins, Franklin, Watson, and
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Crick to the discovery of the structure of DNA? - CORRECT
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ANSWERS ✔✔Wilkins + Franklin = crystal X pattern of helix
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Watson + Crick = model of DNA structure
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3. Based on the carbon numbering system for the sugar (1 - 5)
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that makes up DNA, describe the main component that is
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attached to each carbon and why it is important to the structure
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of DNA. - CORRECT ANSWERS ✔✔The next 5 questions are for
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this...


3. In DNA, C1 is bonded to...
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This is important because... - CORRECT ANSWERS ✔✔-- a
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nitrogenous base (adenine, guanine, cytosine, or thymine) |\ |\ |\ |\ |\ |\




-- this allows the nitrogenous bases to form hydrogen bonds
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-- A-T
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-- C-G
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between the 5`-3` strand and the 3`-5` strand
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3. In DNA, C2 is bonded to...
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,This is important because... - CORRECT ANSWERS ✔✔H
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Importance - C2 does not have a hydroxyl group, which
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distinguishes it from RNA. |\ |\ |\




3. In DNA, C3 is bonded to...
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This is important because... - CORRECT ANSWERS ✔✔OH
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Importance - The C3 of one sugar forms a phosphodiester bond
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with the 5` phosphate of another sugar.
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--- makes phosphodiester chain
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4. In DNA, C4 is bonded to... - CORRECT ANSWERS ✔✔C5
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5. In DNA, C5 is bonded to...
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This is important because... - CORRECT ANSWERS ✔✔phosphate
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Importance - The C5 can be the lead sugar or form
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phosphodiester bonds with the C3 of a second sugar. |\ |\ |\ |\ |\ |\ |\ |\ |\




-- This gives DNA the 5` to 3` linkage.
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, 4. Describe why DNA has directionality. - CORRECT ANSWERS
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✔✔-- 5' end = free phosphate group
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-- 3' end = free hydroxyl (OH) group
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-- DNA is always synthesized in the 5'-to-3' direction = added
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only to the 3' end of the growing strand
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-- G forms 3 hydrogen bonds to C
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-- A forms 2 hydrogen bonds to T
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-- Sequence of DNA has an effect on the structure.
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5. What is the meaning of the term antiparallel in the structure of
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DNA? - CORRECT ANSWERS ✔✔-- orientation is opposite
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-- 5' - 3' polarities are in opposite directions
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6. What does the Meselson and Stahl experiment confirm? -
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CORRECT ANSWERS ✔✔-- complementary base pairing allows us |\ |\ |\ |\ |\ |\ |\ |\


to move that information to the next generation of DNA
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-- semi-conservative model
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7. True/False:
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a.