BIO 340 Exam 1
Questions and
Complete Solutions
Graded A+
Denning [Date] [Course title]
, In a nucleotide, to which carbons on the sugar are the phosphate group and nitrogenous base attached?
- Correct Ans: 5' phosphate, 1' base
In a nucleotide, the phosphate group is attached to the 5' carbon and the nitrogenous base is attached
to the 1' carbon on the sugar
Which property of double stranded DNA was most relevant to deciphering the mechanism by which new
DNA molecules are synthesized? - Correct Ans: complementarity
Complementarity allows each nucleic acid within the double-stranded molecule to function as a
template for the synthesis of new strands
In both prokaryotes and eukaryotes, DNA replication may be described as what? - Correct Ans:
Bidirectional and semiconservative
In most cases, DNA replication proceeds in both directions from an origin of replication (bidirectional)
and existing strand serves as the template for the synthesis of a new strand (semi-conservative)
Compositional analysis of a nucleic acid sample collected at a crime scene reveals that the sample is
comprised of equal parts adenine and uracil, and equal parts guanine and cytosine. The data consistent
with the sample's identity being... - Correct Ans: double stranded RNA.
The sample exhibits RNA characteristics by containing uracil instead of thymine, and its most likely
double stranded because it possesses equal amounts of those bases that form standard Watson-Crick
base pairs (AU and GC)
What is the correct sequence of steps in a typical cycle in a PCR reaction? - Correct Ans: Denaturation,
primer annealing, primer extension
In the denaturation step, the reaction is heated to about 95 degrees C to separate the DNA strands and
expose the templates. In primer annealing, the reaction is cooled to 45-68 degrees C to allow primers to
bind to complementary regions on the template DNA. In primer extension, the reaction is incubated at
about 72 degrees C, the optimal temperature for most heat stable DNA polymerases, to synthesize the
DNA fragment of interest.
Questions and
Complete Solutions
Graded A+
Denning [Date] [Course title]
, In a nucleotide, to which carbons on the sugar are the phosphate group and nitrogenous base attached?
- Correct Ans: 5' phosphate, 1' base
In a nucleotide, the phosphate group is attached to the 5' carbon and the nitrogenous base is attached
to the 1' carbon on the sugar
Which property of double stranded DNA was most relevant to deciphering the mechanism by which new
DNA molecules are synthesized? - Correct Ans: complementarity
Complementarity allows each nucleic acid within the double-stranded molecule to function as a
template for the synthesis of new strands
In both prokaryotes and eukaryotes, DNA replication may be described as what? - Correct Ans:
Bidirectional and semiconservative
In most cases, DNA replication proceeds in both directions from an origin of replication (bidirectional)
and existing strand serves as the template for the synthesis of a new strand (semi-conservative)
Compositional analysis of a nucleic acid sample collected at a crime scene reveals that the sample is
comprised of equal parts adenine and uracil, and equal parts guanine and cytosine. The data consistent
with the sample's identity being... - Correct Ans: double stranded RNA.
The sample exhibits RNA characteristics by containing uracil instead of thymine, and its most likely
double stranded because it possesses equal amounts of those bases that form standard Watson-Crick
base pairs (AU and GC)
What is the correct sequence of steps in a typical cycle in a PCR reaction? - Correct Ans: Denaturation,
primer annealing, primer extension
In the denaturation step, the reaction is heated to about 95 degrees C to separate the DNA strands and
expose the templates. In primer annealing, the reaction is cooled to 45-68 degrees C to allow primers to
bind to complementary regions on the template DNA. In primer extension, the reaction is incubated at
about 72 degrees C, the optimal temperature for most heat stable DNA polymerases, to synthesize the
DNA fragment of interest.
