BIO 311C Exam 3 QUESTIONS AND ANSWERS A+ GRADED
Watson and Crick
developed double helix model of DNA; antiparallel arrangement
essential properties of a molecule of hereditary
sufficient variability to store info, ability to make copies of info, info must be accessible
for gene expression
TH Morgan
showed that genes are located on chromosomes
two components of chromosomes
proteins and DNA
Frederick Griffith
discovered transformation in bacteria; mixing the heat-killed remains of pathogenic
strain with living cells of the harmless strain made them pathogenic
transformation
A change in genotype and phenotype due to the assimilation of foreign DNA
McCarty and MacLeod
"Transforming agent" was DNA
Hershey-Chase Experiment
confirmed that DNA is the genetic material because only radiolabeled DNA could be
found in bacteriophage-infected bacteria
Chargaff's Rules
A=T and C=G
Rosalind Franklin
Used X-ray diffraction to discover the double-helical structure of DNA; image 51; DNA is
a uniform width
Uniform Width of DNA
purine + pyrimidine consistent with x-ray data
DNA composed of subunits called....
nucleotides
Which model did watson and crick's work suggest?
Semi-conservative model
Semi-conservative model
Type of DNA replication in which the replicated double helix consists of one old strand,
derived from the old molecule, and one newly made strand.
Conservative model
Both parental strands stay together after DNA replication
Dispersive model
each strand of both daughter molecules contains a mixture of old and newly
synthesized DNA
Meselson and Stahl
Determined that DNA replication is semiconservative by using DNA nucleotides made
up of different isotopes of N.
DNA replication
, the process of making a copy of DNA
Where does DNA replication begin?
origin of replication
Replication fork
a Y-shaped point that results when the two strands of a DNA double helix separate so
that the DNA molecule can be replicated
Helicase
unwinds parental double helix at replication forks
Single-strand binding protein
Binds to single-stranded DNA until it is used as a template
Topoisomerase
relieves overwinding strain ahead of replication forks by breaking, swiveling, adn
rejoining DNA strands
Primase
synthesizes an RNA primer at 5' end of leading strand and at 5' end of each okazaki
fragment of lagging strand
DNA polymerase III
Using parental DNA as a template, synthesizes new DNA strand by adding nucleotides
to an RNA primer or a pre-existing DNA strand
DNA polymerase I
replaces RNA with DNA; removes RNA nucleotides of primer from 5' end and replaces
them with DNA nucleotides added to 3' end of adjacent fragment
DNA ligase
"glue", joins okazaki fragments of lagging strand; on leading strand, joins 3' end of DNA
that replaces primer to rest of leading strand DNA
DNA polymerases
family of proteins that catalyze DNA synthesis, proof-reads itself
Bacteria have _____ origins of replication
1
Eukaryotes have ______ origins of replication
many
In DNA replication, DNA polymerases add nucleotides only to the free ____ end of
a growing strand
3'
Leading strand
The new continuous complementary DNA strand synthesized along the template strand
in the mandatory 5' to 3' direction. Towards replication fork
Lagging strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki
fragments, each synthesized in a 5' to 3' direction away from the replication fork.
DNA can only elongate in the __ to __ direction
5' to 3'
Steps of Enzymes used in DNA replication - Lagging strand
1) helicase unzips
2) primase makes RNA primer
3) DNA pol III makes okazaki fragment 1
Watson and Crick
developed double helix model of DNA; antiparallel arrangement
essential properties of a molecule of hereditary
sufficient variability to store info, ability to make copies of info, info must be accessible
for gene expression
TH Morgan
showed that genes are located on chromosomes
two components of chromosomes
proteins and DNA
Frederick Griffith
discovered transformation in bacteria; mixing the heat-killed remains of pathogenic
strain with living cells of the harmless strain made them pathogenic
transformation
A change in genotype and phenotype due to the assimilation of foreign DNA
McCarty and MacLeod
"Transforming agent" was DNA
Hershey-Chase Experiment
confirmed that DNA is the genetic material because only radiolabeled DNA could be
found in bacteriophage-infected bacteria
Chargaff's Rules
A=T and C=G
Rosalind Franklin
Used X-ray diffraction to discover the double-helical structure of DNA; image 51; DNA is
a uniform width
Uniform Width of DNA
purine + pyrimidine consistent with x-ray data
DNA composed of subunits called....
nucleotides
Which model did watson and crick's work suggest?
Semi-conservative model
Semi-conservative model
Type of DNA replication in which the replicated double helix consists of one old strand,
derived from the old molecule, and one newly made strand.
Conservative model
Both parental strands stay together after DNA replication
Dispersive model
each strand of both daughter molecules contains a mixture of old and newly
synthesized DNA
Meselson and Stahl
Determined that DNA replication is semiconservative by using DNA nucleotides made
up of different isotopes of N.
DNA replication
, the process of making a copy of DNA
Where does DNA replication begin?
origin of replication
Replication fork
a Y-shaped point that results when the two strands of a DNA double helix separate so
that the DNA molecule can be replicated
Helicase
unwinds parental double helix at replication forks
Single-strand binding protein
Binds to single-stranded DNA until it is used as a template
Topoisomerase
relieves overwinding strain ahead of replication forks by breaking, swiveling, adn
rejoining DNA strands
Primase
synthesizes an RNA primer at 5' end of leading strand and at 5' end of each okazaki
fragment of lagging strand
DNA polymerase III
Using parental DNA as a template, synthesizes new DNA strand by adding nucleotides
to an RNA primer or a pre-existing DNA strand
DNA polymerase I
replaces RNA with DNA; removes RNA nucleotides of primer from 5' end and replaces
them with DNA nucleotides added to 3' end of adjacent fragment
DNA ligase
"glue", joins okazaki fragments of lagging strand; on leading strand, joins 3' end of DNA
that replaces primer to rest of leading strand DNA
DNA polymerases
family of proteins that catalyze DNA synthesis, proof-reads itself
Bacteria have _____ origins of replication
1
Eukaryotes have ______ origins of replication
many
In DNA replication, DNA polymerases add nucleotides only to the free ____ end of
a growing strand
3'
Leading strand
The new continuous complementary DNA strand synthesized along the template strand
in the mandatory 5' to 3' direction. Towards replication fork
Lagging strand
A discontinuously synthesized DNA strand that elongates by means of Okazaki
fragments, each synthesized in a 5' to 3' direction away from the replication fork.
DNA can only elongate in the __ to __ direction
5' to 3'
Steps of Enzymes used in DNA replication - Lagging strand
1) helicase unzips
2) primase makes RNA primer
3) DNA pol III makes okazaki fragment 1
