MCB 102 Exam #1 Questions with correct answers
nucleotide - ✔✔made of a nitrogenous base, a pentose, and a phosphate group
nucleoside - ✔✔nucleotide without a phosphate group
purines - ✔✔two rings, A and G
pyrimidines - ✔✔one ring, C, T, and U
N-beta-glycosyl bond - ✔✔covalent bond between the base of the nucleotide (N-
1 of pyrimidines, N-9 of purines) and the 1' Carbon of the pentose
phosphodiester bond - ✔✔bond linking successive nucleotides: 5'-phosphate
group of one nucleotide is joined to the 3'-hydroxyl group of the next nucleotide
oligonucleotide - ✔✔a short nucleic acid (~50 or fewer nucleotides)
polynucleotide - ✔✔more than 50 nucleotides
hydrophobic - ✔✔purine and pyrimidine bases are hydro______ (phobic/philic?)
3 - ✔✔How many hydrogen bonds are there between G and C?
2 - ✔✔How many hydrogen bonds are there between A and T?
,antiparallel - ✔✔The 2 strands of DNA run _____________.
10.5 - ✔✔How many base pairs are in each complete turn of the helix when the
DNA is in its relaxed state?
Hydrogen bonding and base stacking - ✔✔Which 2 forces hold the double helix
together?
right - ✔✔The B form of DNA is _______ handed.
decreases - ✔✔When subjected to extreme pH or extreme temperature, the
viscosity of a solution of DNA _________.
hypochromic effect - ✔✔Interactions between stacked bases decrease the
absorption of UV light relative to that of a solution with the same concentration
of free nucleotides. Absorption is decreased even further when 2 complementary
strands are paired. This is called the ______________ ______________.
hyperchromic effect - ✔✔Denaturation leads to an increase in absorption of UV
light. This is called the _____________ __________.
higher - ✔✔Higher GC content = __________ (higher/lower?) melting point
AT base pairs - ✔✔DNA replication and transcription are often initiated at sites
rich in ______________.
,detergent - ✔✔The function of __________ in procedures for isolating DNA is to
denature proteins and separate them from DNA.
bacterial transformation - ✔✔a change in properties of the bacterial cell
(phenotype) due to uptake of DNA or RNA from an external source
Hershey - ✔✔This man experimented with the bacteriophage T2, which is 50%
protein and 50% DNA. He radioactively labeled the P's of the DNA and the S's of
the proteins, then treated the infected cells with a blender to remove the external
phage by force. He separated the phage from the bacteria by centrifuge and
found that most of the phage DNA had gotten into the E. coli cells, whereas most
of the protein was released. The cells containing the phage DNA could lyse the
cells and release hundreds of progeny. This experiment confirmed the idea that
DNA is the carrier of genetic information.
transcription - ✔✔the process of forming mRNA on a DNA template
monocistronic - ✔✔a single mRNA molecule that codes for only one polypeptide
is _____________.
polycistronic - ✔✔a single mRNA that codes for multiple different polypeptides is
______________.
2 purines - ✔✔Are base stacking interactions strongest between 2 purines, 2
pyrimidines, or 1 of each?
, B - ✔✔What is the predominant structure of a DNA duplex-- _____ (A/B/Z?)
form?
mutation - ✔✔an alteration in DNA structure that produces a permanent change
in the genetic information
deamination - ✔✔spontaneous loss of a nucleotide's exocyclic amino group
uracil - ✔✔deamination of cytosine results in ____________
AP site - ✔✔hydrolysis of the N-β-glycosyl bond between the base and the
pentose to create a DNA lesion is called an ____ _______.
pyrimidine dimers - ✔✔In the cell, UV irradiation induces __________
___________.
deaminating - ✔✔Nitrous acid and bisulfite are examples of _______________
agents.
oxidative damage - ✔✔This is the most important source of mutagenic
alterations: excited-oxygen species (e.g. hydrogen peroxide, hydroxyl radicals,
superoxide radicals). Cells have defense systems against these but sometimes
these oxidants escape the defenses.
2-adenosylmethionine - ✔✔What do all known DNA methylases use as a methyl
group donor?
nucleotide - ✔✔made of a nitrogenous base, a pentose, and a phosphate group
nucleoside - ✔✔nucleotide without a phosphate group
purines - ✔✔two rings, A and G
pyrimidines - ✔✔one ring, C, T, and U
N-beta-glycosyl bond - ✔✔covalent bond between the base of the nucleotide (N-
1 of pyrimidines, N-9 of purines) and the 1' Carbon of the pentose
phosphodiester bond - ✔✔bond linking successive nucleotides: 5'-phosphate
group of one nucleotide is joined to the 3'-hydroxyl group of the next nucleotide
oligonucleotide - ✔✔a short nucleic acid (~50 or fewer nucleotides)
polynucleotide - ✔✔more than 50 nucleotides
hydrophobic - ✔✔purine and pyrimidine bases are hydro______ (phobic/philic?)
3 - ✔✔How many hydrogen bonds are there between G and C?
2 - ✔✔How many hydrogen bonds are there between A and T?
,antiparallel - ✔✔The 2 strands of DNA run _____________.
10.5 - ✔✔How many base pairs are in each complete turn of the helix when the
DNA is in its relaxed state?
Hydrogen bonding and base stacking - ✔✔Which 2 forces hold the double helix
together?
right - ✔✔The B form of DNA is _______ handed.
decreases - ✔✔When subjected to extreme pH or extreme temperature, the
viscosity of a solution of DNA _________.
hypochromic effect - ✔✔Interactions between stacked bases decrease the
absorption of UV light relative to that of a solution with the same concentration
of free nucleotides. Absorption is decreased even further when 2 complementary
strands are paired. This is called the ______________ ______________.
hyperchromic effect - ✔✔Denaturation leads to an increase in absorption of UV
light. This is called the _____________ __________.
higher - ✔✔Higher GC content = __________ (higher/lower?) melting point
AT base pairs - ✔✔DNA replication and transcription are often initiated at sites
rich in ______________.
,detergent - ✔✔The function of __________ in procedures for isolating DNA is to
denature proteins and separate them from DNA.
bacterial transformation - ✔✔a change in properties of the bacterial cell
(phenotype) due to uptake of DNA or RNA from an external source
Hershey - ✔✔This man experimented with the bacteriophage T2, which is 50%
protein and 50% DNA. He radioactively labeled the P's of the DNA and the S's of
the proteins, then treated the infected cells with a blender to remove the external
phage by force. He separated the phage from the bacteria by centrifuge and
found that most of the phage DNA had gotten into the E. coli cells, whereas most
of the protein was released. The cells containing the phage DNA could lyse the
cells and release hundreds of progeny. This experiment confirmed the idea that
DNA is the carrier of genetic information.
transcription - ✔✔the process of forming mRNA on a DNA template
monocistronic - ✔✔a single mRNA molecule that codes for only one polypeptide
is _____________.
polycistronic - ✔✔a single mRNA that codes for multiple different polypeptides is
______________.
2 purines - ✔✔Are base stacking interactions strongest between 2 purines, 2
pyrimidines, or 1 of each?
, B - ✔✔What is the predominant structure of a DNA duplex-- _____ (A/B/Z?)
form?
mutation - ✔✔an alteration in DNA structure that produces a permanent change
in the genetic information
deamination - ✔✔spontaneous loss of a nucleotide's exocyclic amino group
uracil - ✔✔deamination of cytosine results in ____________
AP site - ✔✔hydrolysis of the N-β-glycosyl bond between the base and the
pentose to create a DNA lesion is called an ____ _______.
pyrimidine dimers - ✔✔In the cell, UV irradiation induces __________
___________.
deaminating - ✔✔Nitrous acid and bisulfite are examples of _______________
agents.
oxidative damage - ✔✔This is the most important source of mutagenic
alterations: excited-oxygen species (e.g. hydrogen peroxide, hydroxyl radicals,
superoxide radicals). Cells have defense systems against these but sometimes
these oxidants escape the defenses.
2-adenosylmethionine - ✔✔What do all known DNA methylases use as a methyl
group donor?
