Mammalian Genetics BCH5413 Exam 1
UPDATED ACTUAL Exam Questions and
CORRECT Answers
Because the DNA was not destroyed, meaning that the pathogenic strain is still able to be taken
up by the healthy DNA, causing death - CORRECT ANSWER - Why does the mouse die
if the researcher mixes the dead pathogenic strain with the live non-pathogenic strain bacteria
and then inject it into the mouse?
When the DNA was completely destroyed; the S strain was no longer able to be pathogenic
without its DNA - CORRECT ANSWER - What was the only scenario in which the mouse
lives? Why?
3.4 A - CORRECT ANSWER - How many angstroms is the distance between stacked base
pairs in DNA?
1953 - CORRECT ANSWER - What year was the structure of DNA discovered?
They did x-ray crystallography to discover the "X" helix pattern of DNA - CORRECT
ANSWER - How did Wilkins and Franklin contribute to the discovery of DNA's structure?
A phosphate, a 5-C sugar, and a nitrogenous base - CORRECT ANSWER - What are the 3
components of a nucleotide?
They made a model of the structure of helical DNA using others' previous research - CORRECT
ANSWER - How did Watson and Crick contribute to the discovery of DNA's structure?
A nitrogenous base (A, G, T, or C) - CORRECT ANSWER - What is attached to the 1' C in
DNA's 5-C sugar?
A and G - CORRECT ANSWER - Which bases are the purines?
,C, T, and U - CORRECT ANSWER - Which bases are the pyrimidines?
True - CORRECT ANSWER - T/F: Purines have a double-ring structure while pyrimidines
have a single-ring structure.
An -H group (if DNA) or an -OH group (if RNA) - CORRECT ANSWER - What is
attached to the 2' C in DNA's 5-C sugar?
An -OH group (will interact with the phosphate on the 5' C of the next nucleotide) - CORRECT
ANSWER - What is attached to the 3' C in DNA's 5-C sugar?
It completes the ring structure (connects the 5' C and 3' C to the oxygen in the ring) - CORRECT
ANSWER - What is attached to the 4' C in DNA's 5-C sugar?
A phosphate group (will interact with the -OH group on the 3' C of the next nucleotide) -
CORRECT ANSWER - What is attached to the 5' C in DNA's 5-C sugar?
The phosphate group losing an oxygen in water - CORRECT ANSWER - What gives
DNA its (-) charge?
It connects from phosphate group -> -OH group -> phosphate group, etc. (never backwards),
which allows the nitrogenous bases to hydrogen bond - CORRECT ANSWER - Why does
DNA have directionality?
One single-strand of DNA is 5' -> 3' and the other strand it connects to is 3' -> 5' (the strands do
not connect in the same direction to form dsDNA) - CORRECT ANSWER - What does it
mean that DNA is antiparallel?
, That DNA replication is semiconservative (the parent strand unzips to allow for synthesis of a
new strand) - CORRECT ANSWER - What does the Meselson and Stahl experiment
(1958) confirm?
True (the presence of 4 bps instead of 3 bps like in the minor groove allows for a more unique
pattern of binding) - CORRECT ANSWER - T/F: The major groove in DNA's structure
allows for more specificity in binding proteins.
False (linear DNA can be supercoiled if in a cell because of its association with proteins) -
CORRECT ANSWER - T/F: Eukaryotic DNA in the nucleus of cells will not supercoil
since it's liner.
False (it needs the presence of other cellular components to supercoil) - CORRECT
ANSWER - T/F: Linear DNA in a test tube (no other substances present) is able to be
supercoiled.
Positive supercoil - CORRECT ANSWER - The type of supercoil in which DNA is twisted
more tightly in the right-hand direction
Negative supercoil - CORRECT ANSWER - The type of supercoil in which DNA is
twisted more loosely in the left-hand direction
Negative supercoil - CORRECT ANSWER - Which type of supercoil allows the DNA to
be more accessible for replication and transcription?
False (GC-rich DNA has more hydrogen bonds and is more stable, giving it a higher melting
temperature) - CORRECT ANSWER - T/F: GC-rich DNA has a lower melting
temperature than AT-rich DNA.
False (A = T and G = C; the amount of purines and pyrimidines in DNA will always be equal;
A+G = C+T) - CORRECT ANSWER - T/F: Chargaff's rule is that A=G and T=C.
UPDATED ACTUAL Exam Questions and
CORRECT Answers
Because the DNA was not destroyed, meaning that the pathogenic strain is still able to be taken
up by the healthy DNA, causing death - CORRECT ANSWER - Why does the mouse die
if the researcher mixes the dead pathogenic strain with the live non-pathogenic strain bacteria
and then inject it into the mouse?
When the DNA was completely destroyed; the S strain was no longer able to be pathogenic
without its DNA - CORRECT ANSWER - What was the only scenario in which the mouse
lives? Why?
3.4 A - CORRECT ANSWER - How many angstroms is the distance between stacked base
pairs in DNA?
1953 - CORRECT ANSWER - What year was the structure of DNA discovered?
They did x-ray crystallography to discover the "X" helix pattern of DNA - CORRECT
ANSWER - How did Wilkins and Franklin contribute to the discovery of DNA's structure?
A phosphate, a 5-C sugar, and a nitrogenous base - CORRECT ANSWER - What are the 3
components of a nucleotide?
They made a model of the structure of helical DNA using others' previous research - CORRECT
ANSWER - How did Watson and Crick contribute to the discovery of DNA's structure?
A nitrogenous base (A, G, T, or C) - CORRECT ANSWER - What is attached to the 1' C in
DNA's 5-C sugar?
A and G - CORRECT ANSWER - Which bases are the purines?
,C, T, and U - CORRECT ANSWER - Which bases are the pyrimidines?
True - CORRECT ANSWER - T/F: Purines have a double-ring structure while pyrimidines
have a single-ring structure.
An -H group (if DNA) or an -OH group (if RNA) - CORRECT ANSWER - What is
attached to the 2' C in DNA's 5-C sugar?
An -OH group (will interact with the phosphate on the 5' C of the next nucleotide) - CORRECT
ANSWER - What is attached to the 3' C in DNA's 5-C sugar?
It completes the ring structure (connects the 5' C and 3' C to the oxygen in the ring) - CORRECT
ANSWER - What is attached to the 4' C in DNA's 5-C sugar?
A phosphate group (will interact with the -OH group on the 3' C of the next nucleotide) -
CORRECT ANSWER - What is attached to the 5' C in DNA's 5-C sugar?
The phosphate group losing an oxygen in water - CORRECT ANSWER - What gives
DNA its (-) charge?
It connects from phosphate group -> -OH group -> phosphate group, etc. (never backwards),
which allows the nitrogenous bases to hydrogen bond - CORRECT ANSWER - Why does
DNA have directionality?
One single-strand of DNA is 5' -> 3' and the other strand it connects to is 3' -> 5' (the strands do
not connect in the same direction to form dsDNA) - CORRECT ANSWER - What does it
mean that DNA is antiparallel?
, That DNA replication is semiconservative (the parent strand unzips to allow for synthesis of a
new strand) - CORRECT ANSWER - What does the Meselson and Stahl experiment
(1958) confirm?
True (the presence of 4 bps instead of 3 bps like in the minor groove allows for a more unique
pattern of binding) - CORRECT ANSWER - T/F: The major groove in DNA's structure
allows for more specificity in binding proteins.
False (linear DNA can be supercoiled if in a cell because of its association with proteins) -
CORRECT ANSWER - T/F: Eukaryotic DNA in the nucleus of cells will not supercoil
since it's liner.
False (it needs the presence of other cellular components to supercoil) - CORRECT
ANSWER - T/F: Linear DNA in a test tube (no other substances present) is able to be
supercoiled.
Positive supercoil - CORRECT ANSWER - The type of supercoil in which DNA is twisted
more tightly in the right-hand direction
Negative supercoil - CORRECT ANSWER - The type of supercoil in which DNA is
twisted more loosely in the left-hand direction
Negative supercoil - CORRECT ANSWER - Which type of supercoil allows the DNA to
be more accessible for replication and transcription?
False (GC-rich DNA has more hydrogen bonds and is more stable, giving it a higher melting
temperature) - CORRECT ANSWER - T/F: GC-rich DNA has a lower melting
temperature than AT-rich DNA.
False (A = T and G = C; the amount of purines and pyrimidines in DNA will always be equal;
A+G = C+T) - CORRECT ANSWER - T/F: Chargaff's rule is that A=G and T=C.
