The product of the bicoid gene in Drosophila provides essential information about
A) the left-right axis.
B) the dorsal-ventral axis.
D) the anterior-posterior axis.
E) lethal genes.
If you were to observe the activity of methylated DNA, you would expect it to
A) have turned off or slowed down the process of transcription.
B) induce protein synthesis by not allowing repressors to bind to it.
C) be unwinding in preparation for protein synthesis.
D) be very actively transcribed and translated.
E) be replicating nearly continuously.
In order to identify a specific restriction fragment using a probe, what must be done?
A) The fragments must be separated by electrophoresis.
B) The fragments must be separated by electrophoresis, the fragments must be treated with heat or chemicals to separate the strands of the double helix, and the probe must be hybridized with the fragment.
C) The fragments must be treated with heat or chemicals to separate the strands of the double helix.
D) The probe must be hybridized with the fragment.
E) The fragments must be separated by electrophoresis and the fragments must be treated
with heat or chemicals to separate the strands of the double helix.
CML (chronic myelogenous leukemia) results from a translocation between human chromosomes 9 and 22. The resulting chromosome 22 is significantly shorter than usual, and it is known as a Philadelphia (Ph') chromosome. The junction at the site of the translocation causes overexpression of a thymine kinase receptor. A new drug (Gleevec or imatinib) has been found to inhibit the disease if the patient is treated early.
Why would Gleevec most probably cause remission of the disease? A) The drug inhibits the replication of the affected chromosome.
B) It eliminates the Ph' chromosome. C) It removes Ph'-containing progenitor cells.
D) It reverses the chromosomal translocation.
E) The drug inhibits the specific thymine kinase receptor.
For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. The researchers will be looking for
A) a pattern shared among some or all of the samples that indicates gene expression differing from control samples.
B) a pattern of fluorescence that indicates which cells are overproliferating.
C) a group of cDNAs that match those in non-breast cancer control samples from the same
D) a group of cDNAs that act differently from those on the rest of the grid.
E) a particular gene that is amplified in all or most of the patient samples.
aE) The drug inhibits the specific thymine kinase receptor.
bA) a pattern shared among some or all of the samples that indicates gene expression differing from control samples
cB) The fragments must be separated by electrophoresis, the fragments must be treated with heat or chemicals to separate the strands of the double helix, and the probe must be hybridized with the fragment.
dA) have turned off or slowed down the process of transcription
eD) the anterior- posterior axis
5 Multiple Choice Questions
C) embryonic stem cells are totipotent, and adult stem cells are pluripotent
D) The BAC carries more DNA, the BAC can carry entire genes and their regulatory elements, and larger BACs are easier to store.
A) T4 protein and T4 DNA
C) organismal cloning
5 True/False Questions
One successful form of gene therapy has involved delivery of an allele for the enzyme adenosine deaminase (ADA) to bone marrow cells of a child with SCID, and delivery of these engineered cells back to the bone marrow of the affected child. What is one major reason for the success of this procedure as opposed to many other efforts at gene therapy?
A) The engineered bone marrow cells from this patient can be used for any other SCID patient.
B) No vector is required to introduce the allele into ADA-negative cells.
C) The engineered cells, when reintroduced into the patient, find their way back to the bone
D) The ADA-introduced allele causes all other ADA-negative cells to die.
E) The immune system fails to recognize cells with the variant gene. → C) The engineered cells, when reintroduced into the patient, find their way back to the bone marrow
Which of the following is characteristic of the product of the p53 gene?
A) It causes cell death via apoptosis.
B) It speeds up the cell cycle.
C) It allows cells to pass on mutations due to DNA damage.
D) It slows down the rate of DNA replication by interfering with the binding of DNA polymerase.
E) It is an activator for other genes. → E) a large number of phages are released at a time
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 → B) increased chromatin condensation
If a particular operon encodes enzymes for making an essential amino acid and is regulated like the trp operon, then
A) the amino acid inactivates the repressor.
B) the amino acid acts as a corepressor.
C) the repressor is active in the absence of the amino acid.
D) the enzymes produced are called inducible enzymes.
E) the amino acid turns on transcription of the operon. → A) a pattern shared among some or all of the samples that indicates gene expression differing from control samples
Some viruses can be crystallized and their structures analyzed. One such virus isDesmodium, or yellow mottle virus, which infects beans. This is a member of the tymovirus group and has a single-stranded RNA genome of ~6,300 nucleotides. Its virion is 25—30 nm in diameter, and is made up of 180 copies of a single capsid protein that self-associate to form each capsomere, which has icosahedral symmetry with 20 facets.
If this virus has a positive RNA strand as its genome, it begins the infection by using this strand as mRNA. Therefore, which of the following do you expect to be able to measure?
A) translation rate
B) formation of new transcription factors
C) accumulation of new ribosomes D) transcription rate
E) replication rate → E) retroviruses