Chp. 7
ORCs of higher eukaryotes interact _____ with origins of replication. indirectly do not interact in any capacity directly
indirectly
Which of the following statements is true regarding DNA polymerase(s) in E. coli? Every DNA polymerase in E. coli has a single, unique function. For example, DNA polymerase I is only active in DNA repair/mutation correction (and has no "true" polymerase activity). E. coli with mutations in DNA polymerase I fail to replicate DNA properly, and cannot be cultured within a laboratory setting. All of the answer options are correct. Although E. coli contain different types of DNA polymerase (i.e., I-V), these polymerase are only ever involved in adding nucleotides to a lengthening DNA strand; these enzymes play no other roles in a bacterial cell. A single E. coli bacterium can contain multiple types of DNA polymerase (i.e., DNA polymerase I-V).
A single E. coli bacterium can contain multiple types of DNA polymerase (i.e., DNA polymerase I-V).
When Griffith injected mice with a mixture of heat-killed S bacteria and live R bacteria, what happened to the mice? All of the mice died. Approximately 25% of the mice died and the remaining 75% lived. Approximately 50% of the mice died and the remaining 50% lived. All of the mice lived. None of the answer options is correct.
All of the mice died.
Which element of DNA replication acts as a "proofreading" function so that the DNA is accurately replicated? DNA polymerase I DNA polymerase III primase All of the answers are correct. Only the first and second answers are correct.
DNA pol I and pol III
DNA that contains many G-C base pairs often requires a high temperature to separate the strands. What characteristic(s) of G-C pairing would explain this? More hydrogen bonds take less energy to break. G-C pairs have three hydrogen bonds, rather than two. DNA always has more G-C pairs. G bases do not normally pair with C bases. None of the answer options are correct.
G-C pairs have three hydrogen bonds, rather than two
A researcher is studying the DNA of goldfish and salamanders. Which of the following will she not find? In goldfish, the amount of G will equal that of C. In salamanders, the amount of A will equal that of T. In goldfish and salamanders, the ratio of (A+T)/(G+C) will be equivalent. The amount of G in DNA derived from brain and muscle cells of salamanders will be the same. All of the answer options are true.
In goldfish and salamanders, the ratio of (A+T)/(G+C) will be equivalent
If you thought about DNA replication as two separate reactions—one reaction replicating the lagging strand and one replicating the leading strand—which element would be in different amounts for the two reactions? Please choose the correct answer from the following choices, and then select the submit answer button. polymerase template DNA nucleotide bases replication fork RNA primers
RNA primers
A researcher has visualized the expression of different proteins during DNA replication in E. coli. He notices that some proteins only ever associate with single (unwound) DNA strands, and appear to be involved in stabilizing DNA. These proteins are likely ______________. topoisomerases SSB proteins β clamp helicases DNA gyrases
SSB proteins
Which model organism has been instrumental in understanding eukaryotic origins of replication? Escherichia coli Saccharomyces cerevisiae Drosophila melanogaster Caenorhabditis elegans All of the answers are correct.
Saccharomyces cerevisiae
Which of the following statements is true regarding the semiconservative model of DNA replication? This model states that after DNA replication, each daughter DNA molecule consists of a new DNA strand and an intact parental DNA strand. This model states that after DNA replication, each daughter DNA molecule only consists of parental DNA. This model states that after DNA replication, each daughter DNA molecule consists of two strands that contain fragments of new DNA interspersed with fragments of parental DNA. The model of semiconservative DNA replication assumes that any of the above answer options can result from DNA replication. This model states that after DNA replication, each daughter DNA molecule consists of only new DNA (i.e., no parental DNA strands).
This model states that after DNA replication, each daughter DNA molecule consists of a new DNA strand and an intact parental DNA strand.
Which of the following statements is true regarding the semiconservative model of DNA replication? This model states that after DNA replication, each daughter DNA molecule consists of a new DNA strand and an intact parental DNA strand. This model states that after DNA replication, each daughter DNA molecule consists of only new DNA (i.e., no parental DNA strands). This model states that after DNA replication, each daughter DNA molecule consists of two strands that contain fragments of new DNA interspersed with fragments of parental DNA. This model states that after DNA replication, each daughter DNA molecule only consists of parental DNA. The model of semiconservative DNA replication assumes that any of the above answer options can result from DNA replication.
This model states that after DNA replication, each daughter DNA molecule consists of a new DNA strand and an intact parental DNA strand.
Recall the three discoveries Erwin Chargaff made while studying DNA: the total amount of pyrimidines (T+C) equals the total amount of purines (A+G), the amount of T equals the amount of A, and the amount of G equals the amount of C. These three "rules" led to what conclusion(s) about DNA base pairing? A purine base pairs with a pyrimidine base. A pairs with T. G pairs with C. All of the answer options are correct. None of the answer options is correct.
all of the options are correct
A researcher is studying different mutations in yeast. He isolates one yeast strain that fails to properly form replisomes. When he assesses the DNA sequences of genes encoding yeast helicase and ORC, he cannot find any mutations. What other gene(s) might be mutated in this yeast strain? DnaA Cdc6 Cdt1 β clamp both Cdc6 and Cdt1
both Cdc6 and Cdt1
A new DNA molecule is being synthesized. In one of the resulting DNA daughter molecules, a T in the parental strand has been incorrectly paired with a G in the newly synthesized strand. This cannot be the result of which of the following? both the T and G bases adopting a keto form the T base adopting an imino form the T base adopting an enol form tautomerization of the T base All of the answer options are correct.
both the T and G bases adopting a keto form
A model of DNA replication in which the parental DNA molecule is maintained and the daughter DNA molecule contains two newly synthesized strands of DNA is called ____________ replication. conjugative semiconservative conservative conservative tautomerative dispersive
conservative
If the experiments of Meselson and Stahl had resulted in them finding a heavy band of DNA and a light band of DNA following centrifugation, what model of DNA replication would this result support? semiconservative conservative conservative tautomerative dispersive conjugative
conservative
DNA gyrase reduces twisting and supercoiling in the DNA in front of the replication fork by ____________ the DNA strands and then ____________ them after DNA gyrase has rotated and released the strain. unwinding; cutting cutting; replicating cutting; rejoining cutting; rejoining rotating; replicating replicating; rejoining
cutting; rejoining
Without the protein caps protecting the 3' single-stranded end of DNA, the end of DNA might be mistaken for a(n) ________________ that could cause the cell to go into senescence or apoptosis. phosphodiester bond double-stranded break 3' overhang mutation origin of replication
double-stranded break
True or False: Newly formed RNA primers used to replicate DNA have a lower mutation rate than the newly formed DNA molecule.
false
The coordination between the two catalytic cores of the pol II holoenzyme is due to α clamp. gyrase. β clamp. helicase. other accessory proteins that form a bridge between the cores.
other accessory proteins that form a bridge between the cores.
In your DNA replication experiments, you notice that the DNA you are replicating tends to form hairpins (a secondary structure that occurs when single-stranded DNA binds to itself). A mutation in what element of DNA replication may be to blame for this occurrence? helicase topoisomerase single-strand-binding proteins clamp proteins All of the answers are correct.
single-strand binding proteins
The ends of chromosomes that are composed of multiple short repeats are known as ________. helicases telomerases telomeres leading strands PCNAs
telomeres
DNA was considered to be too simple a molecule to carry the complex information involved in creating and maintaining complex organisms. Which of the below experiments helped to identify DNA as the genetic material? the experiments of Watson and Crick the experiments of Avery, MacLeod, and McCarty the experiments of Hershey and Chase the experiments of Frederick Griffith the experiments of Avery, Macleod, and McCarty and the experiments of Hershey and Chase.
the experiments of Avery, Macleod, and McCarty and the experiments of Hershey and Chase.
