BIO chapter 9
___and___ performed an experiment that demonstrated the semiconservative mechanism of DNA replication
Meselson and Stahl
Who is credited with the discovery of DNA
Miescher
DNA polymerase synthesizes short fragments of DNA on the lagging strand during DNA replication. These are called what
Okazaki fragments
The researcher who identified that regions of proteins can fold into an alpha helix was
Pauling
Which could possibly have contaminated the cell extract obtained by Avery, MacLeod, and McCarty in their famous experiments
Protein and RNA
What can serve as the genetic material in viruses
RNA or DNA
Of the following choices, which are base paired properly
A-T C-G
Why did the injection of dead smooth bacteria not kill Griffith's mice
Because dead bacteria are unable to cause disease
By about how many times does the 30-nm fiber shorten the nucleosome structure
Seven
In Escherichia call, what enzyme adds DNA nucleotides during DNA replication
DNA polymerase III
DNA replication proceeds outward from two___ , which are the sites where the template strands are unwound and new DNA is synthesized
replication forks
The presence of the sugar___ would definitively identify a nucleic acid as RNA
ribose
The proposed models for DNA replication included
semiconservative replication dispersive replication conservative replication
The nucleosome fiber shortens the length of the DNA molecule about
sevenfold
The length of a metaphase chromosome is___ a chromosome in a non-dividing cell
shorter than
prevents the two DNA template strands from re-forming the double helix
single-strand binding protein
The function of ___ is to coat the single strands of template DNA to prevent them from re-forming a double helix
single-strand binding proteins
Directionally refers to the orientation of
sugar molecules in a DNA strand
The components of a nucleotide are
sugar, phosphate, base
The DNA backbone is composed of alternating
sugars and phosphate groups
The prime symbol is used to distinguish carbons in
sugars from carbons in nitrogenous bases
The DNA strands that can be copied to produce new DNA strands are called the
template strands
In DNA replication the strands on the original molecule are used as___ for the synthesis of new DNA strands
templates
A single turn of the double helix consists of___ base pairs
ten
Griffth's experiments were important because they showed
that the genetic material could be passed form one cell to another
Erwin Chargaff showed that
the amounts of A/T and C/G are equal
replication
the substance that produces the capsule or not
Information
the transformed cells pick up material from dead cells
transmission
the transforming principle is passed via binary fission
Assuming DNA replication had been conservative, Meselson and Stahl would have observed what bands in the centrifuge tube after one round of replication
Two bands: one heavy and one light
In the Avery, McLeod and McCarty experiment, which of the following mixtures would yield smooth colonies when plated
Type R bacteria + type S DNA extract + RNase Type R bacteria + type S DNA extract + protease Type R bacteria + type S DNA extract
___ and ___ proposed that the structure of DNA was a double helix
Watson and Crick
Which of the following helps explain the remarkably high fidelity for DNA replication
The hydrogen bonding between AT and CG pairs is more stable than between mismatched pairs DNA polymerase can identify and repair mismatched nucleotides DNA polymerase is unlikely to catalyze bond formation between adjacent nucleotides if a mismatched base pair is formed
Rosalind Franklin, a British biophysicst, analyzed DNA using___techniques, and proposed that the molecule had a helical structure with a uniform diameter
X-ray diffraction
The major groove of the DNA double helix.
a binding site for proteins that control gene expression
In a DNA chain, adjacent nucleotides are linked via a bond between
a sugar molecule in one and a phosphate group in the other
Which bases are connected by two hydrogen bonds
adenine and thymine
DNA replication relies on the___ of DNA strands according to the___ rule
complementarity;AT/GC
A strand of DNA or RNA is composed of a linear array of nucleotides held together by___ bonds
covalent
During DNA replication, the two original strands of DNA are used to synthesize two
daughter strands
As DNA polymerase slides along the DNA, individual nucleotides with three phosphate groups, called___ , hydrogen-bond to the exposed bases in the___ strand according to the AT/GC rule
deoxynucleoside triphosphates;template
The___ model suggest that DNA replication produces DNA strands in which segments of new DNA are interspersed with the parental DNA
dispersive
The level of DNA structure that resembles a spiral staircase in the
double helix
Purine bases have a___-ring structure and include adenine and____. On the other hand, pyrimidines have a___-ring structure and include cytosine, thymine, and___
double; guanine single;uracil
A nucleosome consists of a core of
eight histone proteins: two each of H2A, H2B, H3 and H4
The less condensed regions of chromosomes are referred to as
euchromatin
The term___ is used to describe the less condensed regions of eukaryotic chromosomes
euchromatin
The term high___ refers to a process that occurs with relatively few mistakes
fidelity
DNA must be compacted in order to
fit in cells
At the replication fork, the enzyme DNA helicase binds to one DNA strand and travels in this direction using energy from ATP
from 5' to 3'
The complete complement of an organism's genetic material is called the
genome
Select all of the following that are purine bases
guanine and adenine
DNA replication of the prokaryotic chromosome
has a single origin of replication and is bidirectional
The enzyme DNA___ separates the DNA strands and keeps the replication fork moving forward
helicase
causes DNA strand separation at the origin of replication
helicase
The term___ is used to describe the highly compacted regions of eukaryotic chromosomes
heterochromatin
___ are a group of proteins that DNA wraps around to compact itself and to form nucleosomes
histones
DNA and RNA are called nucleic acids because they release___ ions in solution and have a net___ charge at neutral pH
hydrogen;negative
X-ray___ patterns are mathematically related to the structural arrangement of atoms causing a scattering pattern, which can be used to explain the three dimensional structure of molecules
diffraction
The orientation of sugar molecules within a DNA strand is referred to as___ . For example, a strand is said to be 5' to 3' or 3' to 5'
directionality
In order for the genetic material to fullfill its role in cells, it must meet which of the following criteria
information replication transmission variation
In DNA replication, the___ strand is made discontinuously in the direction opposite to the movement of the replication fork
lagging
Relative to prokaryotic chromosomes, eukaryotic chromosomees are
larger
During DNA replication, the___ strand is synthesized continuously while the___ strand is synthesized as small fragments that are connected to each other to form a continuous strand
leading;lagging
Nucleosomes are connected by___ regions of DNA that vary in length from 20 to 100 base pairs depending on species and cell type
linking
Injection of which of the following in Griffith's experiments would cause the death of mice
live smooth bacteria + live rough bacteria dead smooth bacteria + live rough bacteria live smooth bacteria
The DNA double helix consists of the___ groove and the___ groove
major and minor
The nuclear___ consists of the nuclear lamina made of protein fibers and other proteins that are connected to the lamina and fill the interior of the nucleus
matrix
During DNA replication in bacteria, only 1 mistake is made per 100___ nucleotides
million
In eukaryotes, the DNA is found in the nucleus,___ and___
mitochondria and chloroplast
Meselson and Stahl used two isotopes of the element___ in their DNA replications experiments, so that the daughter strands could be distinguished from the parental strands
nitrogen
The 30-nm fiber is comprised of___ units organized into a more compact structure
nucleosome
The repeating structural unit of eukaryotic chromatin is the___
nucleosome
DNA is a macromolecule composed of monomers called___
nucleotides
According to the conservative model, DNA replication produces
one molecule with two parental strands and another molecule with two daughter strands.
DNA template strands are referred to as___ strands, while the newly synthesized strands are referred to as___ strands
parental;daughter
The negative charges found in the___ groups of DNA are attracted to the positives charges on___ proteins found in chromatin
phosphate;histone
The 5' end of a DNA strand has a___ group, and the 3' end has a___ group
phosphate;hydroxyl
In a DNA strand, adjacent nucleotides are held together by covalent bonds known as___ bonds
phosphoester
The bacterium Streptococcus pneumoniae causes the disease___ , which can be fatal
pneumonia
The enzyme DNA___ covalently links nucleotides to synthesize new DNA strands together during DNA replication
polymerase
The enzyme works by breaking a bond between the first and second phosphate and attaching a nucleotide dNMP to the 3' end of the DNA strand via a phosphodiester
polymerase
Histone proteins contain a large number of___ amino acids that can bind to the___
positively-charged; negative charges on the phosphates of DNA
Rank the five levels of structural features of DNA. Start at the top with the most complex
1. genome 2. chromosome 3. double helix 4. DNA strand 5. nucleotide
In order to complete synthesis of the Okazaki fragments on the lagging strand, the following must occur
1. the removal of RNA primers 2. the synthesis of DNA in the area where the primers have been removed 3. the covalent joining of adjacent fragments of DNA
Place the steps of eukaryotic chromosomal compaction leading to the metaphase chromosome in the correct order
1. wrapping of DNA around histones 2. formation of a 30-nm fiber via histone H1 and other DNA binding proteins 3. anchoring of radial loop domains to the nuclear matrix 4. further compaction of radial loops to form heterochromatin
During proofreading, DNA polymerase removes the incorrect base in the___ direction, and then adds the correct base in the___ direction
3' to 5'; 5' to 3
A segment of DNA has the sequence 5'-ATGCTT-3'. The complementary sequence would be
3'-TACGAA-5'
A double-stranded DNA molecule contains 20% thymine. The molecule would have to contain___% guanine
30
The compaction of DNA involves interactions between which two of the following
30 nm fibers and nuclear matrix
A human somatic cell contains___ chromosomes
46
DNA helicase travels toward the replication fork using energy form ATP in this direction
5' to 3'
Heterochromatin regions of the chromosome tend to have a diameter of about___ while, euchromatic regions have an average width of about___
700 nm; 300 nm
If a strand of DNA has a T nucleotide, the complementary strand will have which nucleotide paired with the T
A
Avery, McLeod, and McCarty used established biochemical procedures to purify marcomolecules from the type S streptocci. They found out that R bacteria can only be transformed by what type of purified macromolecule
DNA
___ synthesis begins a a site within a chromosome called the origin of replication
DNA
The Avery, MacLeod, and McCarty experiments involved mixing substances with rough bacterial cells.
DNA + RNase DNA + DNase DNA DNA + protease
Which of the following are nucleic acids
DNA and RNA
A chromosome is composed of
DNA and proteins
Chromatin makes up eukaryotic chromosomes and is a complex of
DNA and proteins
Avery, McLeod, and McCarty demonstrated that only purified
DNA can convert type R bacteria into type S
Which of the following processes proceeds according to the AT/GC rule
DNA replication
Of the following structural features of DNA, which comprises all the others
Genome
A process that occurs with relatively few mistakes is described by what terminology
High fidelity
Which of the following are enzymatic features of DNA polymerase
It can only synthesize DNA in the 5' to 3' direction It is unable to begin DNA synthesis on a bare template strand
Which enzyme catalyzes the formation of covalent bonds between adjacent DNA fragments to complete the replication process
Ligase
Which of the following are properties of the DNA double helix proposed by Watson and Crick
The DNA strands are antiparallel The DNA strands obey the AT/GC rule
Which of the following is found in DNA and not in RNA
Thymine
In a DNA double helix, one strand runs 5' to 3' in one direction, while the other goes 3' to 5' in the same direction. This characteristic describes the___ nature of the two strands
antiparallel
Two DNA strands in a double helix that run in opposite directions from one another are said to be___
antiparallel
The genome of a bacterial cell is different from that of a eukaryotic cell because the bacterial genome exists
as a single circular chromosomes
variation
bacteria have the ability to produce a capsule or not
The covalent linkage of a sequence of___ allows DNA to store information
bases
The most current model of chromatin structure suggests that the linker regions in the 30 nm structures are
bent and twisted with little direct contact between nucleosomes
DNA replication is described as___ because DNA replication proceeds outward from two replication forks
bidirectional
The function of single-strand___ proteins is to coat the single strands of template DNA to prevent them from re-forming a double helix
binding
Griffith's experiment demonstrated that the formation of the___ to produce smooth(S) bacteria is governed by genetic material
capsule
The appearance of colonies of Streptoccus pneumoniae is related to the presence or absence of
capsule
The difference between euchromatin and heterochromation relates to the
compaction level of the molecule
The enzyme DNA___ is needed to begin DNA synthesis on a bare template strand. This enzyme makes a short segment of___ RNA called a primer that is complementary to a DNA sequence on the template strand
primase;RNA
In compaction of chromatin, the___ domains are often 25,000 to 200,000 base pairs in size
radial loop
A third level of compaction of eukaryotic chromosomes involves the formation of___ domains in which the 30-nm fibers are anchored to the nuclear matrix to form___
radial loop; euchromatin
DNA polymerase I___ RNA primers in the___ direction
removes; 5' to 3'
Guanine forms ___ hydrogen bonds with cytosine.
three
Guanine forms___ hydrogen bonds with cytosine
three
Relieves coiling in DNA strands ahead of the replication fork
topoisomerase
The enzyme DNA___ relieves coiling in DNA strands ahead of the replication fork
topoisomerase
The semiconservative mechanism of DNA replication produces
two molecules each with a parental strand and a daughter strand
Which of the following are pyrimidine bases
uracil, cytosine, thymine
Watson and Crick deduced the structure of DNA by
using a ball-and-stick model
