Chapter 16 and 17 quiz
a particular triplet of bases in the template strand f DNA is 5' AGT 3'. the corresponding codon for the mRNA transcribed is a. 3'UCA 5' b. 3' UGA 5' c. 5' TCA 3' d. 3' ACU 5' e. either UCA or TCA depending on wobble in the first base
a. 3' UCA 5'
which of the following is not true of RNA processing? a. exons are cut out before mRNA leaves the nucleus b. nucleotides may be added at both ends of the RNA c. ribozymes may function in RNA splicing d. RNA splicing can be catalyzed by spliceosomes e. a primary transcript is often much longer than the final RNA molecule that leaves the nucleus
a. Exons are cut out before mRNA leaves the nucleus.
the anticodon of a particular tRNA molecule is a. complementary to the corresponding mRNA codon b. complementary to the corresponding triplet in rRNA c. the part of tRNA that bonds to a specific amino acid d. changeable, depending on the amino acid that attaches to the tRNA e. catalytic, making the tRNA a ribozyme
a. complementary to the corresponding mRNA codon
in eukaryotic cells, transcription cannot begin until a.several transcription factors have bound to the promoter b. the 5' caps are removed from the mRNA c. the DNA introns are removed from the template d. DNA nucleases have isolated the transcription unit
a.several transcription factors have bound to the promoter
Which component is not directly involved in translation? a. mRNA b. DNA c. tRNA d. ribosomes e. GTP
b. DNA
the following question refers to this figure of a simple metabolic pathway a to enzyme A to b to enzyme b to c according to beadle and Tatum's hypothesis, how many genes are necessary for this pathway? a. 0 b. 1 c. 2 d. 3 e. it cannot be determined from the pathway
c. 2
5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3' which components of the previous molecule will also be found in mRNA in the cytosol? a. 5' UTR I1 I2 I3 UTR 3' b. 5' E1 E2 E3 E4 3' c. 5' UTR E1 E2 E3 E4 UTR 3' d. 5' I1 I2 I3 3' e. 5' E1 I1 E2 I2 E3 I3 E4 3'
c. 5' UTR E1 E2 E3 E4 UTR 3'
in analyzing the number of different bases in a DNA sample, which result would be consistent with the base pairing rules? a. A=G b. A+T=G+T c. A+G=C+T d. A=C e. G=T
c. A+G=C+T
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture? a. nucleotides b. DNA polymerase c. DNA ligase d. primase e. Okazaki fragments
c. DNA ligase
what is the basis for the difference in how leading and lagging strands of DNA molecules are synthesized? a. helices and single-strand binding proteins work at the 5" end b. the origins of replication occur only at the 5' end c. DNA polymerase can join new nucleotides only to the 3' end of a growing strand d. polymerase can work on only one strand at a time e. DNA ligase works only in the 3 to 5 direction
c. DNA polymerase can join new nucleotides only to the 3' end of a growing strand
which of the following statements is true of histones? a. histones are found in mammals, but not in other animals or in plants or fungi b. each nucleosome consists of two molecules of histone H1 c. histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together d. the carboxyl end of each histone extends outward from the nucleosome and is called a histone tail e. the mass of histone in chromatin is approximately nine times the mass of DNA
c. Histone H1 is not present in the nucleosome bead; instead, it draws the nucleosomes together.
the elongation of the leading strand during DNA synthesis a. produces Okazaki fragments b. progresses away from the replication fork c. depends on the action of the DNA polymerase d. does not require a template strand e. occurs in the 3 to 5 direction
c. depends on the action of the DNA polymerase
in a nucleosome, the DNA is wrapped around a. polymerase molecules b. satellite DNA c. histones d. ribosomes e. a thymine dimer
c. histones
In an experiment, DNA is allowed to replicate in an environment with all necessary enzymes, dATP, dCTP, dGTP, and radioactively labeled dTTP (3H thymidine) for several minutes and then switched to nonradioactive medium. It is then viewed by electron microscopy and autoradiography. The figure above represents the results. Which of the following is the most likely interpretation? a. thymidine is only being added where the DNA strands are the furthest apart b. replication proceeds in one direction only c. there are two replication forks going in opposite directions d. thymidine is only added at the very beginning of replication
c. there are two replication forks going in opposite directions
which of the following is not true of a codon? a. it consists of 3 nucleotides b. it may code for the same amino acid as another codon c. it never codes for more than one amino acid d. it extends from one end of a tRNA molecule e. it is the basic unit of the genetic code
d. it extends from one end of a tRNA molecule
E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment? a. one low density band b. one high density and one low density band c. one high density and one intermediate density band d. one low density and one intermediate density band e. one intermediate density band
d. one low density and one intermediate density band
a part of the promoter, called the TATA box, is said to be highly conserved in evolution. which of the following might this illustrate? a. the sequence evolves very rapidly b. the sequence does not mutate c. any ,station in the sequence is selected against d. the sequence is found in many but not all promoters e. the sequence is transcribed at the start of every gene
d. the sequence is found in many but not all promoters
Which of the following mutations would be most likely to have a harmful effect on an organism? a. nucleotide-pair substitution b. a deletion of three nucleotides near the middle of the gene c. a single nucleotide deletion in the middle of an intron d. a single nucleotide deletion near the end of the coding sequence e. a single nucleotide insertion downstream of and close to the start of the coding sequence
e. a single nucleotide insertion downstream or and close to the start of the coding sequence
The spontaneous loss of amino groups from adenine in DNA results in hypoxanthine, an uncommon base, opposite thymine. What combination of proteins could repair such damage? a. DNA ligase, replication fork proteins, adenylyl cyclase b. telomerase, primase, DNA polymerase c. nuclease, telomerase, primase d. telomerase, helices, single strand binding proteins e. nuclease, DNA polymerase, DNA ligase
e. nuclease, DNA polymerase, DNA ligase
in his work with pneumonia-causing bacteria and mice, Griffith found that a. the polysaccharide coat of bacteria caused pneumonia b. bacteriophages injected DNA into bacteria c. the protein coat from pathogenic cells was able to transform nonpathogenic cells d. heat-killed pathogenic cells caused pneumonia e. some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic
e. some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic
