BSCI 170 Exam 4 Study Guide With
Complete Solutions
What are three main "parts" of a nucleotide? - ANSWER a phosphate, sugar, and a
nitrogenous base
What are the four bases found in DNA? RNA? - ANSWER Adenine, Thymine but Uracil for
RNA, Guanine, Cytosine
How do the nucleotides differ in DNA and RNA? - ANSWER DNA is a long polymer with
deoxyriboses and phosphate backbone and RNA is a polymer with a ribose and phosphate
backbone
What are the main features of the Watson and Crick Model of DNA? - ANSWER Double helix
(backbone on the outside and base in middle), Strict Base Pairing (constant diameter, purine;
pyrimidine, A:T and G:C), Anti-Parallel Strands (required for strict base pairing, mediated by
hydrogen bonds)
Why are DNA strands in a double helix anti-parallel? - ANSWER nucleic acid sequence run the
opposite direction, replicating the leading strand in one direction the lagging strand in
another direction.
What is meant by "semiconservative replication"? - ANSWER each DNA strand (parental
strand) serves as a template during the replication process to make s daughter strand along
, its entire length
Where does DNA replication start? - ANSWER an origin; where the double helix beings the
process of unwinding. A replication bubble forms consisting of two replication forks that
move away from each other in opposite directions. as the bubble expands and the forks move
further apart, the new daughter strands are replicated in the bubble.
How is DNA replication different in prokaryotes than in eukaryotes? - ANSWER eukaryotes
involves splicing of RNA ending caps being removed for a mature mRNA while prokaryotes
do not need this
What property of DNA structure causes there to be leading and lagging strands? - ANSWER
the antiparallel structure of DNA causes the need for a lagging strand. the DNA polymerase is
only able to add nucleotides to the 3' end of a growing polynucleotide, making DNA
replication unidirectional. DNA pol III is always moving towards helicase and following the
fork on the leading strand.
What is meant by 5' and 3' ends of nucleic acid strands? - ANSWER ' is prime, indicates the
number of carbons on the DNA sugar's backbone. The 5' has a phosphate group attached to
it while the 3' has an hydroxyl group attached to it
What are all enzymes/proteins that are required for DNA replication? - ANSWER
Topoisomerase, DNA primase, Hlicase, DNA polymerase, RNA primer, DNA ligase, Single
strand Binding proteins, DNA polymerase III
Complete Solutions
What are three main "parts" of a nucleotide? - ANSWER a phosphate, sugar, and a
nitrogenous base
What are the four bases found in DNA? RNA? - ANSWER Adenine, Thymine but Uracil for
RNA, Guanine, Cytosine
How do the nucleotides differ in DNA and RNA? - ANSWER DNA is a long polymer with
deoxyriboses and phosphate backbone and RNA is a polymer with a ribose and phosphate
backbone
What are the main features of the Watson and Crick Model of DNA? - ANSWER Double helix
(backbone on the outside and base in middle), Strict Base Pairing (constant diameter, purine;
pyrimidine, A:T and G:C), Anti-Parallel Strands (required for strict base pairing, mediated by
hydrogen bonds)
Why are DNA strands in a double helix anti-parallel? - ANSWER nucleic acid sequence run the
opposite direction, replicating the leading strand in one direction the lagging strand in
another direction.
What is meant by "semiconservative replication"? - ANSWER each DNA strand (parental
strand) serves as a template during the replication process to make s daughter strand along
, its entire length
Where does DNA replication start? - ANSWER an origin; where the double helix beings the
process of unwinding. A replication bubble forms consisting of two replication forks that
move away from each other in opposite directions. as the bubble expands and the forks move
further apart, the new daughter strands are replicated in the bubble.
How is DNA replication different in prokaryotes than in eukaryotes? - ANSWER eukaryotes
involves splicing of RNA ending caps being removed for a mature mRNA while prokaryotes
do not need this
What property of DNA structure causes there to be leading and lagging strands? - ANSWER
the antiparallel structure of DNA causes the need for a lagging strand. the DNA polymerase is
only able to add nucleotides to the 3' end of a growing polynucleotide, making DNA
replication unidirectional. DNA pol III is always moving towards helicase and following the
fork on the leading strand.
What is meant by 5' and 3' ends of nucleic acid strands? - ANSWER ' is prime, indicates the
number of carbons on the DNA sugar's backbone. The 5' has a phosphate group attached to
it while the 3' has an hydroxyl group attached to it
What are all enzymes/proteins that are required for DNA replication? - ANSWER
Topoisomerase, DNA primase, Hlicase, DNA polymerase, RNA primer, DNA ligase, Single
strand Binding proteins, DNA polymerase III
