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BSC1010H
Ch 16 and 17
| Question | Answer |
|---|---|
| During Griffith's experiments with Streptococcus pneumoniae in mice, material from _____ bacteria transformed _____ bacteria. | heat-killed virulent...living nonvirulent |
| Avery and his colleagues' 1944 experiment showed that DNA _____. | was the substance that transformed the bacteria in Griffith's experiment. |
| A scientist assembles a bacteriophage with the protein coat of phage T2 and the DNA of phate T4. If this composite were allowed to infect a bacterium, the phages produced in the host cell would have _____. | the protein and DNA of T4 |
| Up until Hershey and Chase showed that DNA was the genetic molecule, what molecule was considered the best candidate for carrying genetic information and why? | proteins because they were thought to be the only molecule with both the variety and specificity of function to account for the array of heritable traits observed |
| Monomers for the synthesis of DNA are called _____. | nucleotides |
| Chargaff found that for DNA _____. | the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1 |
| What technique was most helpful to Watson and Crick in developing their model for the structure of DNA? | X-ray crystallography |
| In DNA, the two purines are _____, and the two pyrimidines are _____. | adenine and guanine...cytosine and thymine |
| Adenine forms _____ with thymine; guanine forms _____ with cytosine. | two hydrogen bonds; three hydrogen bonds |
| The two sugar-phosphate strands that form the rungs of a DNA double helix are joined to each other through _____. | hydrogen bonds between nucleotide bases |
| The information in DNA is contained in _____. | the sequence of nucleotides along the length of the two strands of the DNA molecule |
| Who is credited with explaining the structure of the DNA double helix? | Watson and Crick |
| Which of the following attributes of DNA is most crucial to its accurate duplication? | its specific base pairing and hydrogen bonding |
| During the replication of DNA, _____ | both strands of a molecule act as templates |
| The experiments of Meselson and Stahl showed that DNA _____. | replicates in a semiconservative fashion |
| The DNA structures of prokaryotes and eukaryotes are different in several ways, but one way in which they are the same is that ______. | both have a sugar-phosphate backbone |
| Which of the following statements about replication origins is correct? | All of the above* |
| At each end of a DNA replication bubble is ______. | a replication fork |
| The role of DNA polymerases in DNA replication is _____. | attach free nucleotides to the new DNA strand |
| The rate of elongation in prokaryotes is _____ the rate in eukaryotes. | much faster than |
| The two strands of a DNA double helix are antiparallel. This mean that _____. | one strand runs in the 5' to 3' direction, and the other runs in the 3' to 5' direction |
| One strand of a DNA molecule has the base sequence 5'-ATAGGT-3'. The complementary base sequence on the other strand of DNA will be 3'-______-5' | TATCCA |
| DNA polymerase adds nucleotides to the _____ of the leading strands, and to the _____ of the lagging strands (Okazaki fragments). | 3' end...3' end |
| What enzyme joins Okazaki fragments? | DNA ligase |
| After the formation of a replication bubble, which of the following is the correct sequence of enzymes used for the synthesis of the lagging DNA strand? | helicases, primase, DNA polymerases, ligase |
| Which of the following components is required for DNA replication? | RNA primer |
| The removal of the RNA primer and addition of DNA nucleotides to the 3' end of Okazaki fragments in its place is carried out by _____. | DNA polymerase I |
| The unwinding of DNA at the replication fork causes twisting and strain in the DNA ahead of the fork, which is relieved by an enzyme called _____. | topoisomerase |
| Once the DNA at the replication fork is unwound by helicases, what prevents the two strands from coming back together to re-form a double helix? | Single-strand binding proteins bind the unwound DNA and prevent the double helix from re-forming |
| Which description of DNA replication is correct? | Helicases separate the two strands of the double helix, and DNA polymerases then construct two new strands using each of the original strands as templates. |
| In what way(s) is our traditional representation of DNA polymerase molecules moving like locomotives along a track inaccurate? | The proteins involved in replication do no move; instead, DNA is drawn through the complex. DNA polymerase acts as part of a large complex of proteins, not like a single locomotive. |
| The overall error rate in the completed DNA molecule is approximately _____. | 1 error per 10, 000, 000, 000 nucleotides |
| The incorporation of an incorrect base into the DNA during replication _____. | can be repaired by the mismatch repair system |
| Which set of enzymes is involved in nucleotide excision repair? | nuclease, DNA polymerase, and ligase |
| Individuals with the disorder xeroderma pigmentosum _____. | All of the listed responses are correct |
| Unlike prokaryotic DNA replication, replication of eukaryotic chromosomes _____. | cannot be completed by DNA polymerase |
| Telomeres _____. | get shorter with continued cell division |
| Telomerase _____. | is an enzyme that lengthens telomeres |
| Which of the following best illustrates the importance of altered DNA nucleotides in evolutionary processes? | In a temporally variable environment, a population of bacteria with an elevated rate in replication error can have a selective advantage over other populations with lower rates in replication error. |
| What is the major difference between bacterial chromosomes and eukaryotic chromosomes? | Bacteria have a single circular chromosome whereas eukaryotes have several linear chromosomes |
| Put the following DNA-containing entities in order according to the amount of DNA found in their genomes | virus, bacteria, eukaryote |
| Why were many of the early experiments on DNA carried out on viruses and bacteria? | all of the responses are true |
| The "beads on a string" seen in interphase chromatin are ______. | nucleosomes |
| Who formulated the one gene-one enzyme hypothesis? | Beadle and Tatum |
| Genetic information of eukaryotic cells is transferred from the nucleus to the cytoplasm in the form of _____. | RNA |
| Which of the following statements is true? | Each amino acid in a protein is coded for by three bases in the DNA |
| When RNA is being made, the RNA base _____ always pairs with the base _____ in DNA. | U...A |
| Generally speaking, how many genetic codes are there? | One |
| What mRNA codon would be made from the DNA triplet CGT? | GCA |
| The number of nucleotide bases "read" together on the mRNA to designate each amino acid is _____; this unit is called a(n) _____. | three...codon |
| he codons AAA, CCC, GGG, and UUU specify the amino acids lysine, proline, glycine, and phenylalanine respectively. What peptide sequence would be encoded by the sequence 5'-CCCAAATTTGGG-3', if present in the coding strand of the DNA? | pro-lys-phe-gly |
| How many nucleotides are needed to code for a protein with 450 amino acids? | at least 1,350 |
| In many cases, more than one codon codes for the same amino acid. Because of this we say that the code is ______. | redundant |
| Bacteria can transcribe and translate human genes to produce functional human proteins because _____. | the genetic code is nearly universal |
| In a eukaryotic cell, transcription takes place _____. | in the nucleus |
| Which of the following best describes the arrangement of genetic information in a DNA molecule? | The three nucleotide words of a gene are arranged in a nonoverlapping series on the DNA template strand |
| At one point, as a cell carried out its day-to-day activities, the nucleotides GAT were paired with the nucleotides CUA. This pairing occurred _____. | during transcription |
| Which of the following catalyzes the linkage between ribonucleotides to form RNA during gene expression? | RNA polymerase |
| In eukaryotic cells, a terminator in mRNA synthesis is ______. | a specific nucleotide sequence in mRNA that signals the RNA polymerase to stop |
| One strand of a DNA molecule has the following sequence: 3'-AGTACAAACTATCCACCGTC-5'. In order for transcription to occur in that strand, there would have to be a specific recognition sequence, called a(n) _____, to the left of the DNA sequence indicated. | promoter |
| During the transcription of a given portion of a DNA molecule _____. | mRNA is synthesized on only one of the chains |
| In transcription, _____. | All of the listed responses are correct |
| Which of the following statements is false? | In bacteria, proteins called transcription factors enhance the affinity of RNA polymerase to the promoter sites of genes. |
| In eukaryotes, which of the following mechanisms of gene regulation operates after transcription, but before translation of mRNA into protein? | RNA splicing |
| Which of the following accurately describes the usual process of transcription for eukaryotic genes? | Exons are transcribed, but the RNA transcribed from introns does not leave the nucleus. |
| Which of the following statements correctly describes mRNA processing? | Introns are cut out of the primary transcript, and the resulting exons are spliced together. |
| The structures called snRNPs are _____. | part of a spliceosome |
| Nuclei of eukaryotic cells contain spliceosomes that are made up of _____. | snRNA and protein |
| The function of tRNA during protein synthesis is to _____. | deliver amino acids to their proper site during protein synthesis |
| Which of the following summaries of protein synthesis is correct? | Messenger RNA is made on a DNA template, and then amino-acid-bearing transfer RNAs bind to it through codon-anticodon pairing. |
| The bonds that hold tRNA molecules in the correct three-dimensional shape are _____. | hydrogen bonds |
| During translation in a eukaryotic cell _____. | polypeptides are synthesized at ribosomes, according to instructions carried out by mRNA |
| The P site of a ribosome does which of the following? | It holds the tRNA carrying the growing polypeptide chain |
| The first amino acid inserted into a new polypeptide chain in eukaryotic cells is usually _____. | methionine |
| Which of the following is a post-translational modification of a polypeptide? | cleavage of a polypeptide into two or more chains |
| During translation, amino acid chain elongation occurs until _____. | the ribosome encounters a "stop" codon |
| Polysomes may be defined as _____. | groups of ribosomes |
| Cells are able to distinguish proteins destined for secretion or for segregation to specific intracellular compartments from those that will remain in the cytoplasm because _____. | some proteins, as they begin to be synthesized, contain a signal region that causes the ribosome with its growing polypeptide to attach to the ER and translocate the polypeptide into the lumen (space) of the ER. |
| What is the proper order of the following events in the expression of a eukaryotic gene? 1. translation 2. RNA processing 3. transcription 4. modification of protein | 3, 2, 1 ,4 |
| The mRNA codons 5'-CAA-3' or 5'-CAG-3' are translated as the amino acid glutamine by ____. | he same tRNA with the anticodon 3'-GUU-5' |
| Which of the following statements regarding the structure and function of tRNA is false? | Although each tRNA consists of a relatively short, single RNA strand, this single strand can achieve a three-dimensional structure by folding back upon itself and forming covalent bonds between complementary bases. |
| A geneticist found that a particular mutation had no effect on the polypeptide encoded by the gene. This mutation probably involved _____. | a silent or neutral mutation |
| Which of the following types of mutation is least likely to affect the function of the protein corresponding to the gene in which the mutation occurs? | base-pair substitution |
| A base-pair substitution mutation in a germ cell line is likely to have no effect on phenotype if the substitution _____. | occurs in an intron |
| A virus infects a cell and randomly inserts many short segments of DNA containing a stop codon throughout an organism's chromosomes. This will probably cause _____. | manufactured proteins to be short and defective |
| A point mutation in which a single base pair is inserted or deleted from DNA is called a(n) _____. | frame-shift mutation |
| Ultraviolet (UV) radiation is damaging to cells because it _____. | causes mutations in the DNA |
| Transcription factors are found in ______. | archaea and eukaryotes |
| On the off chance that you might contract an archaeal infection, how might it be treated? | None of the listed responses is correct. |
| When genes are expressed, they produce ____. | RNA molecules and polypeptides |
| What is a key difference in gene expression between eukaryotic and prokaryotic cells? | In prokaryotic cells, the mRNA transcript is immediately available as mRNA without processing. |
| What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA? | transcription |
| What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein? | translation |
| What name is given to the process in which pre-mRNA is edited into mRNA? | RNA processing |
| Polypeptides are assembled from _____. | amino acids |
| RNA processing converts the RNA transcript into _____. | mRNA |
| The direction of synthesis of an RNA transcript is _____. | 5' -> 3' |
| What is the process called that converts the genetic information stored in DNA to an RNA copy? | transcription |
| DNA does not store the information to synthesize which of the following? | Organelles |
| Transcription begins at a promoter. What is a promoter? | A site in DNA that recruits the RNA Polymerase |
| Which of the following statements best describes the promoter of a protein-coding gene? | The promoter is a nontranscribed region of a gene |
| What determines which base is to be added to an RNA strand during transcription? | Base pairing between the DNA template strand and the RNA nucleotides |
| Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand? | Complementary |
| What happens to RNA polymerase II after it has completed transcription of a gene? | It is free to bind to another promoter and begin transcription |
| During RNA processing a(n) _____ is added to the 5' end of the RNA. | modified guanine nucleotide |
| During RNA processing a(n) _____ is added to the 3' end of the RNA. | a long string of adenine nucleotides |
| Spliceosomes are composed of _____. | snRNPs and other proteins |
| The RNA segments joined to one another by spliceosomes are ____. | exons |
| Translation occurs in the _____. | cytoplasm |
| Where does translation take place? | Ribosome |
| Which nucleic acid is translated to make a protein? | mRNA |
| Which of the following processes is an example of a post-translational modification? | Phosphorylation |
| Which of the following steps occurs last in the initiation phase of translation? | The large ribosomal subunit joins the complex |
| At which site do new aminoacyl tRNAs enter the ribosome during elongation? | A-site |
| What is meant by translocation? | The ribosome slides one codon down the mRNA |
| True or false. A tRNA with an anticodon complementary to the stop codon catalyzes the reaction by which translation is terminated. | False |
| What enzyme catalyzes the attachment of an amino acid to tRNA? | aminoacyl-tRNA synthetase |
| The tRNA anticodon, GAC, is complementary to the mRNA codon with the sequence _____. | CUG |
| The initiator tRNA attaches at the ribosome's _____ site. | P |
| True or false? A codon is a group of three bases that can specify more than one amino acid. | False. |
| Which of the following statements about mutations is false? | A knock-out mutation results in a total absence of the mutated protein. |
| If a DNA sequence is altered from TAGCTGA to TAGTGA, what kind of mutation has occurred? | Deletion |
| Which mutation(s) would not change the remainder of the reading frame of a gene sequence that follows the mutation(s)? | One addition and one deletion mutation |
| If the sequence ATGCATGTCAATTGA were mutated such that a base were inserted after the first G and the third T were deleted, how many amino acids would be changed in the mutant protein? | Two |
| If a mutated DNA sequence produces a protein that differs in one central amino acid from the normal protein, which of the following kinds of mutations could have occurred? | An addition mutation and a deletion mutation |
| For any given gene, what ultimately determines which DNA strand serves as the template strand? | the base sequence of the gene's promoter |
Created by:
lwelch4