Biology 181 Quiz 6: DNA Replication and Gene Expression
Recombination between linked genes comes about for what reason?
Crossovers between these genes result in chromosomal exchange.
Mendel's second law of independent assortment has its basis in which of the following events of meiosis I?
Alignment of tetrads at the equator.
What is a ribozyme?
An RNA with enzymatic activity.
How do we describe transformation in bacteria?
Assimilation of external DNA into a cell.
At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork: 3' C C T A G G C T G C A A T C C 5' An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence?
5' A C G U U A G G 3'
An Okazaki fragment has which of the following arrangements?
5' RNA nucleotides, DNA nucleotides 3'
The following question refers to the pedigree chart in Figure 14.2 above for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. What is the likelihood that the progeny of IV-3 and IV-4 will have the trait?
50%
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
8%
Of the following, which is the most current description of a gene?
A dna sequence that is expressed to form a functional product: either rna or polypeptide.
Which of the following nucleotide triplets best represents a codon?
A triplet at the opposite end of tRNA from the attachment site of the amino acid.
Hershey and Chase set out to determine what molecule served as the unit of inheritance. They completed a series of experiments in which E. coli was infected by a T2 virus. Which molecular component of the T2 virus actually ended up inside the cell?
DNA
Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?
DNA polymerase III
A new DNA strand elongates only in the 5' to 3' direction because:
DNA polymerase can only add nucleotides to the free 3' end.
Which of the following sets of materials are required by both eukaryotes and prokaryotes for replication?
Double-stranded DNA, four kinds of dNTPS, primers, origins
A frameshift mutation could result from:
Either an insertion or a deletion of a base
To repair a thymine dimer by nucleotide excision repair, in which order do the necessary enzymes act?
Endonuclease, DNA polymerase I, DNA ligase
Which of the following investigators was/were responsible for the following discovery? In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine.
Erwin Chargaff
Why do histones bind tightly to DNA?
Histones are positively charged, and DNA is negatively charged.
Which of the following is a function of a poly-A signal sequence?
It codes for a sequence in eukaryotic transcripts that signals enzymatic cleavage ~1035 nucleotides away.
What is the effect of a nonsense mutation in a gene?
It introduces a premature stop codon into the mRNA.
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together.
Why might a point mutation in DNA make a difference in the level of protein's activity?
It might substitute an amino acid in the active site.
From your understanding of the cell structure, when the newly made polypeptide is to be secreted from the cell where it has been made, what must occur?
Its signal sequence must lead it to the ER, from which it goes to the Golgi.
The following question refers to this table of codons. What amino acid sequence will be generated based on the following mRNA codon sequence? 5' AUG-UCU-UCG-UUA-UCC-UUG 3'
MET-SER-SER-LEU-SER-LEU
In his transformation experiments, what did Griffith observe?
Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
Replication in prokaryotes differs from replication in eukaryotes for which of the following reasons?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
During splicing, which molecular component of the spliceosome catalyzes the excision
RNA
What is the function of topoisomerase?
Relieving strain in the DNA ahead of the replication fork.
Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel arrays. How could these arise?
Replication without separation
It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information in which of the following?
Sequence of bases
Which of the following help(s) to hold the DNA strands apart while they are being replicated?
Single-strand binding proteins
What is meant by the description "antiparallel" regarding the strands that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
The tRNA shown in the figure has its 3' end projecting beyond its 5' end. What will occur at this 3' end?
The amino acid binds covalently.
Which of the following statements is true of linkage?
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.
Which of the following can be determined directly from x-ray diffraction photographs of crystallized DNA?
The diameter of the helix
The leading and the lagging strands differ in that:
The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
What is the function of DNA polymerase III?
To add nucleotides to the 3' end of a growing DNA strand.
The figure represents tRNA that recognizes and binds a particular amino acid (in this instance, phenylalanine). Which codon on the mRNA strand codes for this amino acid?
UUC
A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is:
UUU
Post-translational modifications of proteins may include the _____.
addition of carbohydrates to form a glycoprotein