Microbiology Chapter 13 Pt 1
DNA polymerase I is very important to DNA replication. It removes RNA primers, but it also ______. Multiple choice question. 'Fills-in' the areas where RNA primers used to be with DNA bases Continues synthesizing new DNA after the DNA polymerase III enzyme runs out of energy Fuses together the sugar/phosphate backbone between Okazaki fragments Deletes the sections of DNA where RNA primers used to be
'Fills-in' the areas where RNA primers used to be with DNA bases
Because the oriC locus in E. coli cells is rich in AT base pairs, it has ___________________ hydrogen bonds overall, making it easier for it to become single-stranded to initiate DNA replication.
2
Hershey and Chase utilized _________ to radioactively label bacteriophage DNA and __________ to radioactively label bacteriophage proteins. By doing so, they could follow which molecule type found its way into host cells. Multiple choice question. uranium; plutonium 35S 32P; 35S 35S; 32P 32P
32P; 35S
DNA replication rates in bacteria can approach ______ base pairs per second. Multiple choice question. 10 to 20 20,000 to 100,000 1,000,000+ 750 to 1000
750 to 1000
Which three of the following statements are true regarding the antiparallel nature of double-stranded DNA? Multiple select question. Both strands possess a free hydroxyl group on their 3' ends. Both strands possess a free phosphate group on their 3' ends. Both strands possess a free hydroxyl group on their 5' ends. One strand is oriented in the 5' to 3' direction while the other strand is oriented in the 3' to 5' direction. Both strands are oriented in the 5' to 3' direction in relation to each other. Both strands possess a free phosphate group on their 5' ends.
Both strands possess a free hydroxyl group on their 3' ends. One strand is oriented in the 5' to 3' direction while the other strand is oriented in the 3' to 5' direction. Both strands possess a free phosphate group on their 5' ends.
The enzyme that functions to change the structure of DNA by transiently breaking one or both strands without altering the nucleotide sequence is _____. Multiple choice question. DNA ligase DNA gyrase clamp loader single-strand binding protein
DNA Gyrase
The enzyme ____________ _____________ fuses the sugar/phosphate backbones of adjacent DNA fragments in a newly-synthesized lagging strand of DNA.
DNA Ligase
The enzyme that catalyzes DNA synthesis is ______________ _________________ .
DNA Polymerase
The enzyme that functions to change the structure of DNA by transiently breaking one or both strands without altering the nucleotide sequence is _____. Multiple choice question. DNA ligase DNA gyrase clamp loader single-strand binding protein
DNA gyrase
The enzyme that catalyzes DNA synthesis is _____. Multiple choice question. DNA gyrase DNA synthase DNase DNA polymerase
DNA polymerase
RNA primers made during DNA replication are removed by the activity of the enzyme ________. Multiple choice question. DNA gyrase primase DNA polymerase I DNA polymerase III
DNA polymerase I
RNA primers made during DNA replication are removed by the activity of the enzyme ________. Multiple choice question. primase DNA gyrase DNA polymerase I DNA polymerase III
DNA polymerase I
The reason why the lagging strand is synthesized in a discontinuous fashion is complex. However, the simplest reason behind it is that _____. Multiple choice question. the multiple RNA primers on the lagging strand interrupt DNA polymerase activity at random intervals DNA polymerase can only synthesize chains in a 5' to 3' direction DNA polymerase III can only synthesize DNA in brief runs before it runs out of energy and temporarily stops helicase enzymes can't unwind DNA in a continuous fashion or it will be ripped apart
DNA polymerase can only synthesize chains in a 5' to 3' direction
Unlike ___________ polymerases, __________________ polymerases can initiate synthesis of nucleic acids without an existing free 3' -OH group.
DNA, RNA
Which protein binds to oriC and recruits helicase to initiate DNA replication? Multiple choice question. Theta Primase DnaA DNA gyrase
DnaA
____ enzymes unwind the DNA, while ____ enzymes relieve the torsional stress on the molecules as they're being unwound. Both are required for DNA replication. Multiple choice question. Primase; topoisomerase Topoisomerase; helicase Helicase; topoisomerase Helicase; SSB
Helicase; topoisomerase
Why is it a good thing that DNA replication is high-fidelity (low-error)? Multiple choice question. It doesn't matter if it is or isn't - there are repair mechanisms to resolve errors after replication. If it weren't, we'd have a large number of potentially damaging mutations introduced each time DNA was replicated. It isn't - a lot of errors are made during replication. This is what drives evolution forward. If it weren't, the process couldn't take place at all and no DNA would ever be replicated.
If it weren't, we'd have a large number of potentially damaging mutations introduced each time DNA was replicated.
Which three of the following are true of a helicase? Multiple select question. It works after the replication fork has passed through the DNA. It uses energy obtained from ATP hydrolysis. It works ahead of the DNA replication fork. It uses energy obtained from GTP hydrolysis. It is responsible for unwinding the 2 template strands of parent DNA. It is responsible for rewinding DNA strands back together after synthesis.
It uses energy obtained from ATP hydrolysis. It works ahead of the DNA replication fork. It is responsible for unwinding the 2 template strands of parent DNA.
Which three of the following are true of a helicase? Multiple select question. It works after the replication fork has passed through the DNA. It uses energy obtained from GTP hydrolysis. It uses energy obtained from ATP hydrolysis. It works ahead of the DNA replication fork. It is responsible for unwinding the 2 template strands of parent DNA. It is responsible for rewinding DNA strands back together after synthesis.
It uses energy obtained from ATP hydrolysis. It works ahead of the DNA replication fork. It is responsible for unwinding the 2 template strands of parent DNA.
Proteins responsible for preventing unpaired DNA from re-annealing until the DNA replication machinery replicates the template are called ________________. (Use the abbreviation.)
SSBs
Which three of the following events occur at the DNA replication fork? Multiple select question. The DNA helix is unwound. The fork moves towards the origin during replication. One fork moves away from the origin site in one direction during replication. Two new DNA strands are synthesized and paired together. Two new DNA strands are synthesized, paired with their parent template strands. Two forks move in opposite directions from the origin site during replication.
The DNA helix is unwound. Two new DNA strands are synthesized, paired with their parent template strands. Two forks move in opposite directions from the origin site during replication.
After radioactively labeling DNA and proteins in 2 separate batches of bacteriophage, E. coli cells were infected with each batch. When the infection was interrupted and bacteria were pelleted using a centrifuge, which pairing showed radioactivity in the cell pellet and why? Multiple choice question. The cells infected with the radioactive DNA bacteriophage, were in the pellet because DNA is the carrier of genetic information in some viruses. Both cell pellets exhibited radioactivity because the entire virus particle is brought into the host cell during infection. Neither cell pellet exhibited radioactivity because neither proteins nor DNA are the carriers of genetic information in any viruses. The cells infected with the radioactive protein bacteriophage, because proteins are the carriers of genetic information in some viruses.
The cells infected with the radioactive DNA bacteriophage, were in the pellet because DNA is the carrier of genetic information in some viruses.
During DNA replication, DNA polymerases require a primer (of either DNA or RNA) to begin synthesis of DNA. Why? Multiple choice question. They need a 'starting point' free 5' phosphate group to attach nucleotides to. They need a 'starting point' free 3' phosphate group to attach nucleotides to. They need a 'starting point' free 5' hydroxyl group to attach nucleotides to. They need a 'starting point' free 3' hydroxyl group to attach nucleotides to.
They need a 'starting point' free 3' hydroxyl group to attach nucleotides to.
Why does DNA polymerase require an RNA primer before it can do its job? Multiple choice question. The active site of DNA polymerase requires binding of an RNA molecule in addition to the DNA template and incoming deoxynucleotide. RNA is bound by the clamp loader proteins, which load the beta clamp, which binds the DNA polymerase III - RNA is necessary for the next steps. An RNA primer stabilizes the structure of single-stranded DNA, preventing it from falling apart prior to replication. Unlike RNA polymerase, it requires a free 3' -OH group to attach deoxynucleotides to.
Unlike RNA polymerase, it requires a free 3' -OH group to attach deoxynucleotides to.
Which three pieces of evidence did Fred Griffith use to infer that there was something from the dead virulent bacteria that was capable of transforming the living avirulent bacteria into a virulent form? Multiple select question. When the mixture of both was injected into mice, the mice died and virulent living bacteria were isolated from them. When avirulent bacteria were boiled prior to injection into mice, they killed the animals. When boiled avirulent bacteria were mixed with living virulent bacteria before injection, living virulent bacteria were isolated from the animals. Mice were killed by living virulent bacteria. When virulent bacteria were boiled prior to injection into mice, they lost the ability to kill the mice. Mice were killed by living avirulent bacteria.
When the mixture of both was injected into mice, the mice died and virulent living bacteria were isolated from them. Mice were killed by living virulent bacteria. When virulent bacteria were boiled prior to injection into mice, they lost the ability to kill the mice.
DNA replication in a circular bacterial chromosome begins at _____. Multiple choice question. a single random point in the chromosome random points throughout the chromosome multiple specific origin of replication sites a single specific origin of replication site
a single specific origin of replication site
Which of the following apply to the product of the primase enzyme? Multiple select question. about 35 bases long complementary to the RNA about 10 bases long complementary to the DNA DNA RNA
about 10 bases long complementary to the DNA RNA
DNA polymerase catalyzes the formation of a phosphodiester bond between an existing DNA strand and _____. Multiple choice question. an RNA primer strand a molecule of pyrophosphate its complementary DNA strand an incoming nucleoside triphosphate
an incoming nucleoside triphosphate
DNA polymerase catalyzes the formation of a phosphodiester bond between an existing DNA strand and _____. Multiple choice question. an RNA primer strand its complementary DNA strand a molecule of pyrophosphate an incoming nucleoside triphosphate
an incoming nucleoside triphosphate
The term ___________ is used to describe the situation where one strand of DNA is oriented in the 5' to 3' direction while its complementary strand is oriented in the reverse 3' to 5' direction.
antiparallel
The major and minor grooves of DNA are formed as the two _______ (of the slightly offset DNA strands) are twisted around each other. Multiple choice question. adenines backbones deoxyriboses nucleotides
backbones
The _______ and ________ proteins are very important to the DNA replication activities of DNA polymerase III holoenzymes, but they don't directly add nucleotides themselves. Multiple choice question. SSBs; primase primase; beta clamp clamp loader; beta clamp
clamp loader; beta clamp
The _______ and ________ proteins are very important to the DNA replication activities of DNA polymerase III holoenzymes, but they don't directly add nucleotides themselves. Multiple choice question. primase; beta clamp clamp loader; beta clamp SSBs; primase
clamp loader; beta clamp
The energy required to form a new phosphodiester bond between two deoxyribonucleotides during DNA replication comes from _____. Multiple choice question. the proton motive force hydrolyzing ATP cleaving the covalent bond between the 1st and 2nd phosphate groups on the incoming deoxyribonucleotide cleaving the covalent bond between the 2nd and 3rd phosphate groups on the incoming deoxyribonucleotide
cleaving the covalent bond between the 1st and 2nd phosphate groups on the incoming deoxyribonucleotide
The energy required to form a phosphodiester bond in DNA is obtained from _________________ the covalent bond between the first and second phosphate groups on the incoming deoxyribonucleotide, releasing __________________ from the nucleotide that is added.
cleaving, energy
A phosphodiester bond is a _______ chemical bond between adjacent sugars of deoxynucleotides in DNA. Multiple choice question. radioactive hydrogen ionic covalent
covalent
Topoisomerase resolves catenated daughter chromosomes by _____. Multiple choice question. creating a double-stranded break in one chromosome, then rejoining the strands after the 2 chromosomes are separated creating a double-stranded break in both chromosomes, releasing them from each other inducing strong negative supercoiling, separating them inducing strong positive supercoiling, separating them
creating a double-stranded break in one chromosome, then rejoining the strands after the 2 chromosomes are separated
DNA is a polymer consisting of deoxyribonucleotides nucleotides nitrogen-containing bases carbons
deoxyribonucleotides
The sugar molecule found in DNA is _______, while the sugar molecule used in RNA is ________. Multiple choice question. glucose; lactose ribose; deoxyribose lactose; deoxyribose ribose; glucose deoxyribose; ribose
deoxyribose; ribose
Due to the polarity orientation of the template for the lagging strand, a new RNA primer must be laid down every so often to provide a new free 3' -OH group for the DNA polymerase to begin synthesis. This is the reason why the lagging strand is synthesized in a __________ manner.
discontinuous
Due to the polarity orientation of the template for the lagging strand, a new RNA primer must be laid down every so often to provide a new free 3' -OH group for the DNA polymerase to begin synthesis. This is the reason why the lagging strand is synthesized in a __________________________ manner.
discontinuous
Which two of the following activities apply to DNA gyrase? Multiple select question. alters the nucleotide sequence at the origin keeps the two strands separated during replication does not alter the nucleotide sequence transiently breaks one or two DNA strands provides orientation for the replication fork
does not alter the nucleotide sequence transiently breaks one or two DNA strands
DNA polymerase I can 'fill-in' the gaps left between Okazaki fragments after RNA primers are deleted because _______. Multiple choice question. each DNA end of an Okazaki fragment provides the needed free 3' phosphate group for DNA polymerase I each DNA end of an Okazaki fragment provides the needed free 5' -OH group for DNA polymerase I each DNA end of an Okazaki fragment provides the needed free 3' -OH group for DNA polymerase I
each DNA end of an Okazaki fragment provides the needed free 3' -OH group for DNA polymerase I
The term 'semiconservative' in DNA replication means that ______. Multiple choice question. each double-stranded molecule produced will contain 1 parent strand and 1 new daughter strand the process uses both parent strands to produce a molecule composed of 2 new daughter strands only 1/2 of the genetic information is conserved in each round of replication - the other 1/2 is new genetic information the process utilizes energy conservation mechanisms in 1/2 of its steps
each double-stranded molecule produced will contain 1 parent strand and 1 new daughter strand
Each Okazaki fragment begins with its own RNA primer because _____. Multiple choice question. primase randomly lays down RNA primers along the newly-created DNA strands each fragment needs to have a free 3' phosphate group for DNA polymerase each fragment needs to have a free 5' -OH group for DNA polymerase each fragment needs to have a free 3' -OH group for DNA polymerase
each fragment needs to have a free 3' -OH group for DNA polymerase
Avery and his colleagues used _______ to selectively destroy DNA, RNA, or protein in purified extracts of virulent pneumococci. Multiple choice question. heat radiation enzymes violent shaking (sonication)
enzymes
The epsilon (ε) subunit of the DNA polymerase III core enzyme possesses a 3' to 5' ___________ activity required for proofreading of replicated DNA.
exonuclease
When purified virulent pneumococci DNA was introduced to avirulent pneumococci, Avery and his colleagues observed _____. Multiple choice question. no death in test animals death of test mice only growth of avirulent pneumococci, indicating DNA was NOT the agent of transformation growth of virulent pneumococci, indicating DNA was the agent of transformation
growth of virulent pneumococci, indicating DNA was the agent of transformation
The enzyme responsible for unwinding DNA in front of the replication fork is ____________.
helicase
If topoisomerase enzymes weren't present in a cell during DNA replication, the most likely outcome would be _____. Multiple choice question. induction of positive supercoiling, inhibiting DNA replication no change at all - topoisomerase enhances but is not critical to the process faster DNA replication due to faster unwinding of DNA by helicases strong induction of negative supercoiling, enhancing DNA replication
induction of positive supercoiling, inhibiting DNA replication
If topoisomerase enzymes weren't present in a cell during DNA replication, the most likely outcome would be _____. Multiple choice question. induction of positive supercoiling, inhibiting DNA replication strong induction of negative supercoiling, enhancing DNA replication faster DNA replication due to faster unwinding of DNA by helicases no change at all - topoisomerase enhances but is not critical to the process
induction of positive supercoiling, inhibiting DNA replication
In E. coli, the oriC locus is a good point for the initiation of DNA replication because _____. Multiple choice question. it is rich in AT base pairs it has specific sequences to bind helicases it has specific sequences to bind DNA polymerase III holoenzyme it is rich in GC base pairs
it is rich in AT base pairs
During DNA replication, the ______ strand is replicated by the replisome in the direction opposite to the movement of the replication fork. Multiple choice question. leading lagging
lagging
During DNA replication, one strand of DNA is replicated as the replisome moves in the same direction as the replication fork. This strand is called the _____ strand. Multiple choice question. lagging leading
leading
The purpose of the clamp loader protein associated with DNA polymerase III is to _____. Multiple choice question. load the beta clamp protein onto the DNA unwind the template double-stranded DNA load the DNA polymerase III onto the DNA load the incoming deoxyribonucleotides onto the DNA polymerase III active site
load the beta clamp protein onto the DNA
DNA replication could be categorized as a ____. (Choose all that apply) Multiple select question. high-error process low-fidelity process low-error process high-fidelity process
low-error process high-fidelity process
When the two strands of DNA are twisted around each other, due to being slightly offset from each other, a wide _______ groove and a narrower _______ groove are formed by the backbones of each strand. Multiple choice question. major; minor minor; major
major; minor
Bacterial DNA is generally found in a ________________, supercoiled state.
negative
To initiate DNA replication, DnaA binds to the region known as ____________ and recruits _______________ enzyme to denature the DNA.
oriC, Helicase
The _______________ of replication is the specific site on a circular bacterial chromosome where DNA replication begins.
origin
The backbone structure of DNA possesses a _______________ chemical group between the deoxyribose portions of two adjacent deoxyribonucleotides.
phosphate
DNA polymerase catalyzes the formation of a(n) _____ bond between an existing DNA strand and an incoming nucleoside triphosphate. Multiple choice question. ionic phosphodiester hydrogen
phosphodiester
The backbone of DNA molecules is formed by ___________________ bonds between individual deoxynucleotides.
phosphodiester
A short RNA strand of around 10 nucleotides complementary to the DNA template is the product of the _____ enzyme. Multiple choice question. DNA polymerase primase DNA ligase helicase
primase
The enzyme _________ works to synthesize a short stretch of RNA complementary to the parent strand to begin synthesis of DNA by DNA polymerase III enzymes.
primase
The enzyme _____________ works to synthesize a short stretch of RNA complementary to the parent strand to begin synthesis of DNA by DNA polymerase III enzymes.
primase
The enzyme that synthesizes RNA primers as complements to the template strand of DNA as needed to begin DNA replication is _____. Multiple choice question. topoisomerase helicase DNA polymerase primase
primase
Each Okazaki fragment must begin with its own RNA __________ to provide a free 3' -OH group for DNA polymerase to attach deoxyribonucleotides.
primer
DNA ligase is very important to DNA replication because it _____. Multiple choice question. reforms the sugar/phosphate backbone between Okazaki fragments deletes the sections of DNA where RNA primers used to be 'fills-in' the areas where RNA primers used to be with DNA bases continues synthesizing new DNA after the DNA polymerase III enzyme runs out of energy
reforms the sugar/phosphate backbone between Okazaki fragments
DNA polymerase I works to ___________ RNA primers from newly-synthesized DNA.
remove
The place at which DNA is synthesized during replication is called the _____. Multiple choice question. DNA polymerase replication fork telomere replicon
replication fork
Ribose in RNA is different from deoxyribose in DNA because ______. Multiple choice question. ribose has a hydroxyl group attached to the 2' carbon ribose is composed of 5 carbons instead of 6 ribose is composed of 6 carbons instead of 5 ribose lacks a hydroxyl group attached to the 2' carbon, having instead a hydrogen
ribose has a hydroxyl group attached to the 2' carbon
DNA replication uses each parent strand as a template to produce a new daughter strand. In the replicated molecules, each has one parent strand and one newly-synthesized daughter strand. The term used to describe this phenomenon is __________ DNA replication. Multiple choice question. base-pairing conservative semiconservative complementary
semiconservative
The proteins that keep the two parental template strands apart during DNA replication are _____. Multiple choice question. beta clamps helicases single-stranded DNA binding proteins DNA polymerase holoenzymes
single-stranded DNA binding proteins
The coiling of a coil (such as that found in double-stranded DNA) is called ___________.
supercoiling
The term used to describe the phenomenon when double-stranded helical DNA twists around on itself is _____. Multiple choice question. complementarity antiparallel binding supercoiling hydrogen bonding
supercoiling
The function of primase during DNA replication is to _____. Multiple choice question. synthesize a short strand of RNA to provide a starting point for DNA polymerase III to keep DNA from supercoiling during the unwinding process synthesize a short strand of DNA to provide a starting point for DNA polymerase III prevent unwound strands from simply rewinding with each other ahead of the DNA replication fork
synthesize a short strand of RNA to provide a starting point for DNA polymerase III
The function of primase during DNA replication is to _____. Multiple choice question. to keep DNA from supercoiling during the unwinding process synthesize a short strand of DNA to provide a starting point for DNA polymerase III synthesize a short strand of RNA to provide a starting point for DNA polymerase III prevent unwound strands from simply rewinding with each other ahead of the DNA replication fork
synthesize a short strand of RNA to provide a starting point for DNA polymerase III
Which three of the following components does DNA polymerase require to catalyze the synthesis of DNA? Multiple select question. template DNA nucleotides deoxyribonucleotides a primer (DNA or RNA) to provide a free 5' hydroxyl group a primer (DNA or RNA) to provide a free 3' hydroxyl group template RNA
template DNA deoxyribonucleotides a primer (DNA or RNA) to provide a free 3' hydroxyl group
The purpose of the beta clamp protein associated with the DNA polymerase III enzyme is to _____. Multiple choice question. tether incoming deoxyribonucleotides to the DNA polymerase III active site unwind the double-stranded DNA template create the phosphodiester bond between incoming deoxyribonucleotides tether the DNA polymerase III core enzyme to the template DNA
tether the DNA polymerase III core enzyme to the template DNA
Guanine pairs with cytosine using ______ noncovalent hydrogen bonds, while adenine pairs with thymidine using ______ noncovalent hydrogen bonds. Multiple choice question. three; two two; two two; three four; two
three; two
If DNA is unwound very rapidly, positive supercoiling may result, which may impede replication. The enzyme used to help relieve this problem is called ____. Multiple choice question. helicase single-strand binding protein clamp loader topoisomerase
topoisomerase
The enzyme capable of resolving the problem of catenated daughter chromosomes is ______. Multiple choice question. helicase topoisomerase DNA polymerase I DNA polymerase III
topoisomerase
DNA helicase unwinds DNA with the aid of ____ and keeps the DNA strands separated using ____. Multiple choice question. topoisomerases; single-strand binding proteins (SSBs) topoisomerases; clamp loaders DNA polymerase III; topoisomerases DNA polymerase III; single-strand binding proteins (SSBs)
topoisomerases; single-strand binding proteins (SSBs)
Which two of the following activities apply to DNA gyrase? Multiple select question. transiently breaks one or two DNA strands does not alter the nucleotide sequence provides orientation for the replication fork keeps the two strands separated during replication alters the nucleotide sequence at the origin
transiently breaks one or two DNA strands does not alter the nucleotide sequence
True or false: Bacteria like E. coli replicate their genomes at an amazing speed of about 750 to 1,000 base pairs per second. True false question. True False
true
True or false: Bacterial DNA is generally negatively supercoiled. True false question. True False
true
In the Griffith transformation experiment, when living avirulent bacteria were mixed with _____ killed bacteria before being injected into mice, the mice died.
virulent
Which subunit of DNA polymerase III core enzyme possesses the 3' to 5' exonuclease activity required for proofreading? Multiple choice question. tau dimers ε (epsilon) subunit clamp loaders beta clamps
ε (epsilon) subunit
