5 Written questions
5 Matching questions
- During DNA replication,
A) methylation of the DNA is maintained because DNA polymerase directly incorporates
methylated nucleotides into the new strand opposite any methylated nucleotides in the
B) methylation of the DNA is maintained because methylation enzymes act at DNA sites
where one strand is already methylated and thus correctly methylates daughter strands
C) methylated DNA is copied in the cytoplasm, and unmethylated DNA is copied in the
D) DNA polymerase is blocked by methyl groups, and methylated regions of the genome are
therefore left uncopied.
E) all methylation of the DNA is lost at the first round of replication.
- Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
B) genetic material composed of nucleic acid
C) cell division
E) independent existence
- Which of the following is an example of post-transcriptional control of gene expression?
A) the folding of DNA to form heterochromatin
B) the binding of transcription factors to a promoter
C) the removal of introns and alternative splicing of exons
D) the addition of methyl groups to cytosine bases of DNA
E) gene amplification contributing to cancer
- RNA viruses require their own supply of certain enzymes because A) these enzymes translate viral mRNA into proteins.
B) host cells rapidly destroy the viruses.
C) these enzymes cannot be made in host cells.
D) host cells lack enzymes that can replicate the viral genome.
E) these enzymes penetrate host cell membranes.
- Why are BACs preferred today rather than bacteriophages for making genomic libraries?
A) The BAC can carry entire genes and their regulatory elements.
B) The BAC carries more DNA.
C) Larger BACs are easier to store.
D) The BAC carries more DNA, the BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
E) The BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
- a D) The BAC carries more DNA, the BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
- b C) the removal of introns and alternative splicing of exons
- c D) host cells lack enzymes that can replicate the viral genome
- d B) methylation of the DNA is maintained because methylation enzymes act at DNA sites where one strand is already methylated and thus correctly methylates daughter strands after replication
- e B) genetic material composed of nucleic acid
5 Multiple choice questions
- D) single nucleotide polymorphisms found only in persons with a particular disorder
- B) bacteria cannot remove eukaryotic introns
- C) The viral envelope mediates entry into the cell, the capsid entry into the nuclear membrane, and the genome is all that enters the nucleus.
- D) become capable of human-to-human transmission
- D) the anterior- posterior axis
5 True/False questions
A researcher found a method she could use to manipulate and quantify phosphorylation and methylation in embryonic cells in culture. In one set of experiments she succeeded in decreasing methylation of histone tails. Which of the following results would she most likely see?
A) inactivation of the selected genes B) increased chromatin condensation
C) abnormalities of mouse embryos D) decreased chromatin condensation
E) decreased binding of transcription factors → E) bind to complementary regions of target mRNAs
RNAi methodology uses double-stranded pieces of RNA to trigger a breakdown or blocking of mRNA. For which of the following might it more possibly be useful?
A) to decrease the production from a harmful gain-of-function mutated gene
B) to raise the rate of production of a needed digestive enzyme
C) to raise the concentration of a desired protein
D) to destroy an unwanted allele in a homozygous individual
E) to form a knockout organism that will not pass the deleted sequence to its progeny → D) Dicer enzyme has reduced it to smaller double-stranded pieces
You isolate an infectious substance that is capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, viroid, or prion. You have four methods at your disposal that you can use to analyze the substance in order to determine the nature of the infectious agent.
I. treating the substance with nucleases that destroy all nucleic acids and then determining whether it is still infectious
II. filtering the substance to remove all elements smaller than what can be easily seen under a light microscope
III. culturing the substance by itself on nutritive medium, away from any plant cells
IV. treating the sample with proteases that digest all proteins and then determining whether it is still infectious
Which treatment could definitively determine whether or not the component is a viroid?
E) first II and then III → E) bind to complementary regions of target mRNAs
The herpes viruses are very important enveloped DNA viruses that cause disease in all vertebrate species and in some invertebrates such as oysters. Some of the human ones are herpes simplex (HSV) I and II, causing facial and genital lesions, and the varicella-zoster (VSV), causing chicken pox and shingles. Each of these three actively infect nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can then reactivate, replicate again, and be infectious to others.
In order to be able to remain latent in an infected live cell, HSV must be able to shut down what process?
A) all immune responses
B) transcription of viral genes
C) DNA replication
D) apoptosis of a virally infected cell
E) interaction with histones → D) apoptosis of a virally infected cell
Which of the following best describes siRNA?
A) a molecule, known as Dicer, that can degrade other mRNA sequences
B) a short double-stranded RNA, one of whose strands can complement and inactivate a sequence of mRNA
C) a portion of rRNA that allows it to bind to several ribosomal proteins in forming large or small subunits
D) a single-stranded RNA that can, where it has internal complementary base pairs, fold into cloverleaf patterns
E) a double-stranded RNA that is formed by cleavage of hairpin loops in a larger precursor → E) a large number of phages are released at a time