BackMutations in the CFTR gene result in cystic fibrosis in humans, a condition in which abnormal secretions are present in the lungs, pancreas, and sweat glands. The gene was mapped to a 500-kb region on chromosome 7 containing three candidate genes.
Using your knowledge of the disease symptoms, how would you distinguish between the candidate genes to decide which is most likely to encode the CFTR gene?
In a bacterial culture in which all cells are unable to synthesize leucine (leu⁻), a potent mutagen is added, and the cells are allowed to undergo one round of replication. At that point, samples are taken, a series of dilutions are made, and the cells are plated on either minimal medium or minimal medium containing leucine. The first culture condition (minimal medium) allows the growth of only leu⁺ cells, while the second culture condition (minimal medium with leucine added) allows growth of all cells. The results of the experiment are as follows:
What is the rate of mutation at the locus associated with leucine biosynthesis?
Yeast are single-celled eukaryotic organisms that grow in culture as either haploids or diploids. Diploid yeast are generated when two haploid strains fuse together. Seven haploid mutant strains of yeast exhibit similar normal growth habit at 25°C, but at 37°C, they show different growth capabilities. The table below displays the growth pattern.
Researchers induce fusion in pairs of haploid yeast strains (all possible combinations), and the resulting diploids are tested for their ability to grow at 37°C. The results of the growth experiment are shown below. How many different genes are mutated among these seven yeast strains? Identify the strains that represent each gene mutation.
Yeast are single-celled eukaryotic organisms that grow in culture as either haploids or diploids. Diploid yeast are generated when two haploid strains fuse together. Seven haploid mutant strains of yeast exhibit similar normal growth habit at 25°C, but at 37°C, they show different growth capabilities. The table below displays the growth pattern.
Hypothesize about the nature of the mutation affecting each of these mutant yeast strains, including why strains B and G display different growth habit at 37°C than the other strains.
Most organisms display a circadian rhythm, a cycling of biological processes that is roughly synchronized with day length (e.g., jet lag occurs in humans when rapid movement between time zones causes established circadian rhythms to be out of synch with daylight hours). In Drosophila, pupae eclose (emerge as adults after metamorphosis) at dawn.
In most plants, such as Arabidopsis, genes whose encoded products have roles related to photosynthesis have expression patterns that vary in a circadian manner. Using this knowledge, how would you screen for Arabidopsis mutants that have an impaired circadian rhythm?
Most organisms display a circadian rhythm, a cycling of biological processes that is roughly synchronized with day length (e.g., jet lag occurs in humans when rapid movement between time zones causes established circadian rhythms to be out of synch with daylight hours). In Drosophila, pupae eclose (emerge as adults after metamorphosis) at dawn.
Using this knowledge, how would you screen for Drosophila mutants that have an impaired circadian rhythm?
Assume that a mutation affects the gene for each of the following eukaryotic RNA polymerases. Match each mutation with the possible effects from the list provided. More than one effect is possible for each mutation.
Ribosomal RNA is not processed.
Assume that a mutation affects the gene for each of the following eukaryotic RNA polymerases. Match each mutation with the possible effects from the list provided. More than one effect is possible for each mutation.
Some tRNA is not synthesized.
Assume that a mutation affects the gene for each of the following eukaryotic RNA polymerases. Match each mutation with the possible effects from the list provided. More than one effect is possible for each mutation.
Some rRNA is not synthesized.
Assume that a mutation affects the gene for each of the following eukaryotic RNA polymerases. Match each mutation with the possible effects from the list provided. More than one effect is possible for each mutation.
Pre-mRNA does not have introns removed.