BCH 5413 ACTUAL TEST QUESTIONS WITH
COMPLETE ANSWER KEY
●● 1. In the experiment described that supports DNA as the genetic
material:
b.
What was the only scenario in which the mouse lives? Why?
Answer: -- When DNA of the S strain was destroyed
-- DNA that caused the virulence factors is destroyed = no function
●● 2. What were the contributions of Wilkins, Franklin, Watson, and
Crick to the discovery of the structure of DNA?
Answer: Wilkins + Franklin = crystal X pattern of helix
Watson + Crick = model of DNA structure
●● 3. Based on the carbon numbering system for the sugar (1 - 5) that
makes up DNA, describe the main component that is attached to each
carbon and why it is important to the structure of DNA.
Answer: The next 5 questions are for this...
,●● 3. In DNA, C1 is bonded to...
This is important because...
Answer: -- a nitrogenous base (adenine, guanine, cytosine, or thymine)
-- this allows the nitrogenous bases to form hydrogen bonds
-- A-T
-- C-G
between the 5`-3` strand and the 3`-5` strand
●● 3. In DNA, C2 is bonded to...
This is important because...
Answer: H
Importance - C2 does not have a hydroxyl group, which distinguishes it
from RNA.
●● 3. In DNA, C3 is bonded to...
This is important because...
Answer: OH
,Importance - The C3 of one sugar forms a phosphodiester bond with the
5` phosphate of another sugar.
--- makes phosphodiester chain
●● 4. In DNA, C4 is bonded to...
Answer: C5
●● 5. In DNA, C5 is bonded to...
This is important because...
Answer: phosphate
Importance - The C5 can be the lead sugar or form phosphodiester bonds
with the C3 of a second sugar.
-- This gives DNA the 5` to 3` linkage.
●● 4. Describe why DNA has directionality.
Answer: -- 5' end = free phosphate group
-- 3' end = free hydroxyl (OH) group
, -- DNA is always synthesized in the 5'-to-3' direction = added only to the
3' end of the growing strand
-- G forms 3 hydrogen bonds to C
-- A forms 2 hydrogen bonds to T
-- Sequence of DNA has an effect on the structure.
●● 5. What is the meaning of the term antiparallel in the structure of
DNA?
Answer: -- orientation is opposite
-- 5' - 3' polarities are in opposite directions
●● 6. What does the Meselson and Stahl experiment confirm?
Answer: -- complementary base pairing allows us to move that
information to the next generation of DNA
-- semi-conservative model
●● 7. True/False:
a.
COMPLETE ANSWER KEY
●● 1. In the experiment described that supports DNA as the genetic
material:
b.
What was the only scenario in which the mouse lives? Why?
Answer: -- When DNA of the S strain was destroyed
-- DNA that caused the virulence factors is destroyed = no function
●● 2. What were the contributions of Wilkins, Franklin, Watson, and
Crick to the discovery of the structure of DNA?
Answer: Wilkins + Franklin = crystal X pattern of helix
Watson + Crick = model of DNA structure
●● 3. Based on the carbon numbering system for the sugar (1 - 5) that
makes up DNA, describe the main component that is attached to each
carbon and why it is important to the structure of DNA.
Answer: The next 5 questions are for this...
,●● 3. In DNA, C1 is bonded to...
This is important because...
Answer: -- a nitrogenous base (adenine, guanine, cytosine, or thymine)
-- this allows the nitrogenous bases to form hydrogen bonds
-- A-T
-- C-G
between the 5`-3` strand and the 3`-5` strand
●● 3. In DNA, C2 is bonded to...
This is important because...
Answer: H
Importance - C2 does not have a hydroxyl group, which distinguishes it
from RNA.
●● 3. In DNA, C3 is bonded to...
This is important because...
Answer: OH
,Importance - The C3 of one sugar forms a phosphodiester bond with the
5` phosphate of another sugar.
--- makes phosphodiester chain
●● 4. In DNA, C4 is bonded to...
Answer: C5
●● 5. In DNA, C5 is bonded to...
This is important because...
Answer: phosphate
Importance - The C5 can be the lead sugar or form phosphodiester bonds
with the C3 of a second sugar.
-- This gives DNA the 5` to 3` linkage.
●● 4. Describe why DNA has directionality.
Answer: -- 5' end = free phosphate group
-- 3' end = free hydroxyl (OH) group
, -- DNA is always synthesized in the 5'-to-3' direction = added only to the
3' end of the growing strand
-- G forms 3 hydrogen bonds to C
-- A forms 2 hydrogen bonds to T
-- Sequence of DNA has an effect on the structure.
●● 5. What is the meaning of the term antiparallel in the structure of
DNA?
Answer: -- orientation is opposite
-- 5' - 3' polarities are in opposite directions
●● 6. What does the Meselson and Stahl experiment confirm?
Answer: -- complementary base pairing allows us to move that
information to the next generation of DNA
-- semi-conservative model
●● 7. True/False:
a.
