Chapter 9: The Information of Life
This symbol is used to distinguish the numbering of carbons in the sugars of nucleic acid from the numbering of carbons in the nitrogenous bases.
'
A single turn of the double helix consists of _____ base pairs.
10
How many base pairs make up one turn of the double helix?
10
The typical number of mistakes during bacterial DNA replication is 1 per ______ nucleotides.
100,000,000
A nucleosome is composed of _____________ or _________________ base pairs of DNA wrapped around a core of eight histone proteins called a histone octamer.
146; 147
If a bacterial chromosome consists of 30% adenine, what is the percentage of cytosine?
20%
A Meselson-Stahl experiment is performed on a bacterial culture. What percentage of DNA molecules is expected to be of intermediate density after three rounds of replication?
25%
Guanine forms __________________ hydrogen bonds with cytosine.
3
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
Histone H1 and other proteins are important in the formation of the ____________ -nm fiber, which shortens the nucleosome structure another sevenfold.
30
Nucleosomes are organized into a more compact structure known as the ________ with the help of the histone protein ________.
30-nm fiber ; H1
A human somatic cell contains _______ chromosomes.
46
The number of chromosomes in a human somatic cell is
46
DNA helicase travels toward the replication fork using energy from ATP in this direction
5' to 3'
Once synthesis has begun, DNA can only be synthesized in a _______ direction
5' to 3'
Which bases are paired properly?
A-T C-G
DNA replication is very accurate because: 1. Hydrogen bonding according to the _____________ rule is more stable than mismatched base pairs; 2. DNA polymerase is unlikely to catalyze bond formation if an incorrect base is added; and 3. DNA polymerase carries out __________________.
AT/GC; proofreading
Why did the injection of dead smooth bacteria not kill Griffith's mice?
Because dead bacteria are unable to cause disease
_______ analyzed the base composition of DNA from different species and proposed that the amount of adenine in each case is equal to the amount of thymine.
Chargaff
Avery, McLeod, and McCarty used established biochemical procedures to purify macromolecules from the type S streptococci. They found out that R bacteria can only be transformed by what type of purified macromolecule?
DNA
________ synthesis begins at a site within a chromosome called the origin of replication.
DNA
The Avery, MacLeod, and McCarty experiments involved mixing substances with rough bacterial cells. Select all of the combinations of substances that they added to the rough bacterial cells.
DNA + DNase DNA + protease DNA DNA + RNase
Which are nucleic acids?
DNA and RNA
Avery, McLeod, and McCarty demonstrated that only purified
DNA can convert type R bacteria into type S.
Which enzyme is responsible for removing the RNA primers?
DNA polymerase I
In Escherichia coli, what enzyme adds DNA nucleotides during DNA replication?
DNA polymerase III
Which of the following helps explain the remarkably high fidelity for DNA replication?
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 The hydrogen bonding between AT and CG pairs is more stable than between mismatched pairs
During what process are parental DNA strands used as templates for the synthesis of new DNA strands?
DNA replication
Which of the following processes proceeds according to the AT/GC rule?
DNA replication
Chromatin makes up eukaryotic chromosomes and is a complex of
DNA; proteins
Which of the following is found in DNA but not in RNA?
Deoxyribose
The model organism used by Meselson and Stahl was
Escherichia coli
Which histone protein is bound to the linker region?
H1
Which of the following are examples of histone proteins found anywhere in chromatin?
H1 H3 H2B H2A H4
An octamer of histone proteins contains two of each of these proteins.
H2A H4 H3 H2B
DNA and RNA are called nucleic acids because they release ________________+ ions in solution and have a net ______________ charge at neutral pH.
H; negative
What statement about the genetic material is true?
It is DNA in all living organisms, but can be RNA in viruses.
Which are enzymatic features of DNA polymerase?
It is unable to begin DNA synthesis on a bare template strand It can only synthesize DNA in the 5' to 3' direction
___________ and ___________ performed an experiment that demonstrated the semiconservative mechanism of DNA replication. (Last names only please)
Meselsohn; Stahl
Who is credited with the discovery of DNA?
Miescher
Meselson and Stahl used two isotopes of the element __________________ in their DNA replication experiments, so that the daughter strands could be distinguished from the parental strands.
Nitrogen
______________ fragments are a series of DNA segments made on the lagging strand during DNA replication.
Okazaki
DNA polymerase synthesizes short fragments of DNA on the lagging strand during DNA replication. These are called what?
Okazaki fragments
A linear DNA strand contains two ends: the 5 prime end has a free _______ group, while the 3 prime end has a free _______ group.
P ; OH
The 5 prime end of a DNA strand has a ____________ group, and the 3 prime end has a ________ group.
P; OH
The researcher who identified that regions of proteins can fold into an alpha helix was
Pauling
A nucleotide has three components:
Phosphate group, pentose (five-carbon sugar), and a nitrogenous base
The nucleotides in the backbone of the DNA strand are held together by what type of bond?
Phosphodiester
Which enzyme is required to initiate DNA synthesis on a bare template strand?
Primase
What can serve as the genetic material in viruses?
RNA or DNA
What could possibly have contaminated the cell extract obtained by Avery, MacLeod, and McCarty in their famous experiments?
RNA, protein
The two nucleic acids are
RNA; DNA
Two potential contaminants in the Avery, MacLeod, and McCarty experiments were _____________ and ________________.
RNA; protein
What statement best describes the results of the Avery, McLeod, and McCarty experiment that show DNA causes transformation in Streptococcus pneumoniae?
S. pneumoniae DNA degraded chemically does not cause transformation.
Which end of one strand of DNA within a double helix is next to the 5' end of the other strand within that helix?
The 3' end
Which are properties of the DNA double helix proposed by Watson and Crick?
The DNA strands obey the AT/GC rule The DNA strands are antiparallel
Which of the following statements about DNA replication is TRUE?
The leading strand is synthesized continuously while the lagging strand is synthesized in a series of small fragments that are later connected
Which of the following is found in DNA and not in RNA?
Thymine
Why do eukaryotic cells have multiple origins of replication?
To ensure timely replication of multiple, relatively large chromosomes
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
Who determined the double helix structure of DNA using ball-and-stick models and experimental observations by Wilkins and Franklin?
Watson and Crick
_________ and ___________ proposed that the structure of DNA was a double helix. (Last names only please)
Watson; Crick
In a DNA chain, adjacent nucleotides are linked via a bond between
a sugar molecule in one and a phosphate group in the other
If a strand of DNA has a T nucleotide, the complementary strand will have which nucleotide paired with the T?
adenine
Purine bases include __________ and ___________. (No abbreviations please).
adenine; guanine
Which bases are connected by two hydrogen bonds?
adenine; thymine
In a DNA double helix, one strand runs in one direction, while the other is upside down relative to the first one. This characteristic describes the ___________ nature of the two strands.
antiparallel
The term used to describe two DNA strands that run in opposite directions from each other is
antiparallel
Two DNA strands in a double helix that run in opposite directions from one another are said to be
antiparallel
Watson and Crick proposed that the structure of DNA is a double helix in which the DNA strands are ________ and obey the ________ rule.
antiparallel; AT/GC
The genome of a bacterial cell is different from that of a eukaryotic cell because the bacterial genome exists
as a single circular chromosome
variation
bacteria have the ability to produce a capsule or not
Watson and Crick used a ____________ -and- ______________ approach to deduce that the structure of DNA was a double helix.
ball; stick
The components of a nucleotide are
base phosphate sugar
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 term ________ refers to DNA replication proceeding 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
During his experiments, Frederick Griffith made observations that matched the four criteria for the genetic material. For example, the substance conferring the ability to make a(n) __________________ must be replicated (criterion 2), and then transmitted (criterion 3) from mother to daughter cells during division.
capsule
Griffith's experiments demonstrated that the formation of the ______ to produce smooth (S) bacteria is governed by genetic material.
capsule
The appearance of colonies of Streptococcus pneumoniae is related to the presence or absence of
capsules
A nucleosome is a repeating structural unit of eukaryotic
chromatin
_______________ is a DNA-protein complex that makes up eukaryotic chromosomes.
chromatin
The cell structure that contains DNA is the
chromosome
In order to fit into cells, DNA must be
compacted
The difference between euchromatin and heterochromatin relates to the
compaction level of the molecule
The ability to predict the DNA sequence in one strand based on the sequence of another strand is referred to as
complementarity
The pairing of C with G exemplifies the definition of
complementarity
DNA replication relies on the ________ of DNA strands according to the ________ rule.
complementarity; AT/GC
When cells prepare to divide, the chromosomes become ______ to aid in proper alignment.
condensed
The __________ model suggests that DNA replication produces one double helix with both parental strands and the other with two new daughter strands.
conservative
The nucleotides of a single DNA or RNA strand are linked by:
covalent bonds (In a double helix, two strands of DNA are held together by hydrogen bonds. However, the nucleotides within each single strand of DNA (or RNA) are held together by phosphodiester bonds, which are covalent bonds.)
A strand of DNA or RNA is composed of a linear array of nucleotides held together by ______________ bonds.
covalent or phosphoester
Pyrimidine bases include
cytosine; thymine; uracil
During DNA replication, the two original strands of DNA are used to synthesize two
daughter strands
As a cell prepares to divide, the space between the 30 nm fibers of each chromosome
decreases
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 triphosphate; template
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
directionality
The lagging strand is made
discontinuously in the opposite direction of the replication fork
The ______________ model suggests that DNA replication produces DNA strands in which segments of new DNA are interspersed with the parental DNA.
dispersive
The interaction of two strands of DNA via hydrogen bonds results in a structure called the
double helix
The level of DNA structure that resembles a spiral staircase is 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
Heterochromatin involves a tighter packing of loops as compared to
euchromatin
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
Energy is generated to covalently connect adjacent molecules by breaking the bond between the
first and second phosphates in the dNTP
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'
Of the following structural features of DNA, which has the highest level of complexity?
genome
The complete complement of an organism's genetic material is called the:
genome
Which are purine bases?
guanine adenine
In a DNA double helix, cytosine is paired with
guanine by three hydrogen bonds.
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
The enzyme that causes DNA strand separation at the origin of replication is
helicase
During replication, the enzyme DNA ___________ uses energy from ATP to separate the two strands. This generates additional coiling ahead of the replication fork that is alleviated by another enzyme called DNA __________________.
helicase; topoisomerase
The highly compacted regions of chromosomes are called
heterochromatin
The term ______________ is used to describe the highly compacted regions of eukaryotic chromosomes.
heterochromatin
A process that occurs with relatively few mistakes is described by what terminology?
high fidelity
DNA is compacted by wrapping itself around a group of proteins called
histones
______________ are a group of proteins that DNA wraps around to compact itself and to form nucleosomes.
histones
A typical eukaryotic chromosome may be ______ of millions of base pairs long.
hundreds
DNA polymerase III
is the major replication enzyme.
In DNA replication, the ______ strand is made discontinuously in the direction opposite to the movement of the replication fork.
lagging
Relative to a prokaryotic chromosomes, eukaryotic chromosomes 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
The replication process is completed when the enzyme DNA _________________ forms a covalent bond between adjacent DNA fragments.
ligase
Which enzyme catalyzes the formation of covalent bonds between adjacent DNA fragments to complete the replication process?
ligase
Nucleosomes are connected by _____________ regions of DNA that vary in length from 20 to 100 base pairs depending on species and cell type.
linker
Of the following choices, which type of Streptococcus pneumoniae would lead to death if injected into a mouse?
live smooth
Injection of which of the following in Griffith's experiments would cause the death of mice?
live smooth bacteria live smooth bacteria + live rough bacteria dead smooth bacteria + live rough bacteria
The two types of grooves seen in the double helix are the
major and minor
The DNA double helix consists of the ______________ groove and the ______________ groove.
major; minor
The primary purpose of the Meselson-Stahl experiment was to determine the
mechanism of DNA replication
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; chloroplast
A metaphase chromosome is ______ a chromosome in a non-dividing cell.
more condensed than
Compared to the same chromosome in a nondividing cell, a metaphase chromosome is
much shorter
The compaction of DNA involves interactions between which two of the following?
nuclear matrix 30 nm fibers
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
The building blocks of DNA are
nucleotides
According to the conservative model, DNA replication produces
one molecule with two parental strands and another molecule with two daughter strands
The ____________ of replication is a site within a chromosome where DNA replication begins.
origin
Nucleotides are linked together by phosphoester bonds -- between phosphorus and
oxygen
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
In a DNA strand, adjacent nucleotides are held together by covalent bonds known as ___________ bonds.
phosphoester
The enzyme DNA ________________ covalently links nucleotides to synthesize new DNA strands together during DNA replication.
polymerase
The enzyme responsible for covalently linking nucleotides together to form DNA strands is called DNA
polymerase
This 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 bond.
polymerase
Histone proteins contain a large number of __________ amino acids that can bind to the __________.
positively-charged ; negative charges on the phosphates of DNA
The capsule present on Streptococcus pneumoniae
prevents the immune system from killing the organism
The enzyme DNA ________________ is needed to begin DNA synthesis on a bare template strand. This enzyme makes a short segment of ______________ called a primer that is complementary to a DNA sequence on the template strand.
primase; RNA
An RNA _________________ is required to produce each Okazaki fragment in Escherichia coli.
primer
DNA polymerase can detect a mismatched nucleotide and remove it from the daughter strand. It does so by digesting the linkages in the 3' to 5' direction to remove the incorrect base and then changing direction to synthesize again in the 5' to 3' direction. This process is called:
proofreading
A chromosome is composed of two macromolecules. Which ones?
protein DNA
The difference between purine and pyrimidines is that
purines have a double ring structure and pyrimidines have a single ring structure
DNA polymerase cleaves the bond connecting the first two phosphates in an incoming deoxynucleoside triphosphate causing the release of a molecule of ____________________ (PPi).
pyrophosphate
Rosalind Franklin, a British biophysicist, analyzed DNA using X-_________ _____________ techniques, and proposed that the molecule had a helical structure with a uniform diameter.
ray; diffraction
Nucleic acids are named such because they
release H+ in solutions
DNA polymerase I ______ RNA primers in the ______ direction.
removes; 5' to 3'
DNA replication proceeds outward from two ______________ ______________, which are the sites where the template strands are unwound and new DNA is synthesized.
replication forks
During DNA synthesis, the sites where the two template strands are unwound and new DNA is made are called what?
replication forks
For a molecule to serve as the genetic material, it must meet the following key criteria: information, ___________________, ______________________, and _______________________.
replication, transmission, variation
The presence of the sugar _____________ would definitively identify a nucleic acid as RNA.
ribose
As a result of the mechanism of ___________ DNA replication, the new double-stranded DNA contains one parental strand and one daughter strand.
semiconservative
The proposed models for DNA replication included
semiconservative replication dispersive replication conservative replication
Three different models for the mechanism of DNA replication have been proposed. These are _____________ , _____________, and _____________.
semiconservative; conservative; dispersive
The 30-nm fiber shortens the length of the nucleosome structure about:
sevenfold
These coat the strands of template DNA to block the re-formation of the double helix
single-strand binding proteins
If a mouse died after infection with Streptococcus pneumoniae, Griffith would be able to find what type of bacteria in its blood?
smooth live
In the 1950s, American chemist Linus Pauling proposed that
some regions of proteins fold into a structure known as an alpha helix
Directionality refers to the orientation of
sugar molecules in a DNA strand
The prime symbol is used to distinguish carbons in
sugars from carbons in nitrogenous bases.
During DNA replication, the parental DNA strand can also be called a(n) ______________ strand, because it is used for the synthesis of a daughter strand of DNA.
template
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
Griffith's experiments were important because they showed
that the genetic material could be passed from one cell to another
Erwin Chargaff showed that
the amounts of A/T and C/G are equal
The genome is
the entire complement of an organism's genetic material.
If a rough type of Streptococcus pneumoniae is injected into a mouse, you would expect
the mouse not to die.
X-ray diffraction patterns can be used to determine
the structural arrangement of atoms in DNA
replication
the substance that produces the capsule can be copied
information
the transformed cells pick up material from dead cells
transmission
the transforming principle is passed via binary fission
In DNA, adenine normally pairs _____________ with and cytosine normally pairs with _________________.
thymine; guanine
The enzyme DNA ________ relieves coiling in DNA strands ahead of the replication fork.
topoisomerase
Which enzyme alleviates the coiling in DNA strands just ahead of the replication fork?
topoisomerase
In order for the genetic material to fulfill its role in cells, it must meet which of the following criteria?
transmission information variation replication
In a DNA double helix, adenine and thymine on opposite strands are connected to each other via ___________ hydrogen bonds.
two
According to the dispersive model, DNA replication produces
two molecules each containing strands that have a mixture of parental and daughter DNA
The semiconservative mechanism of DNA replication produces
two molecules each with a parental strand and a daughter strand
In experiments by Avery, MacLeod, and McCarty, what experimental mixtures converted type R bacteria into type S bacteria?
type R bacteria plus purified DNA from a type S strain type R bacteria plus purified DNA from a type S strain plus RNase type R bacteria plus purified DNA from a type S strain plus protease
The presence of ______ would definitely identify a substance as RNA.
uracil
Which are pyrimidine bases?
uracil thymine cytosine
Watson and Crick deduced the structure of DNA by
using a ball-and-stick model
DNA was first isolated in 1869 from the nuclei of
white blood cells
Franklin determined that the structure of DNA was helical based on
x-ray diffraction analysis
