Q1) A student researcher is trying to figure out if she has found an allele of a
ID: 269593 • Letter: Q
Question
Q1) A student researcher is trying to figure out if she has found an allele of a new gene, or an allele of a gene already known. The mutant affects body color and changes normal yellow flies to black. She crosses the mutant to three different black flies, representing different genes, B1, B2 and B3. The first and second crosses produce wildtype (yellow) flies whereas the third cross produces black flies. Did she find a new gene? What type of cross did she do?
No, she found a new allele of the B3 gene when she did a complementation test
Q2) How does one differentiate between polygenic traits and pleiotropic alleles?
one allele of one gene masks the effects of multiple alleles of another gene
both polygenic traits and pleiotropic alleles alter expected Mendelian ratios
one allele masks the effects of other alleles of the same gene
one trait is affected by multiple genes, one allele affects multiple traits
one gene, one enzyme
Q3) You are mapping a new gene. You cross a m1m2/m1m2 double mutant with a wild type strain to produce a dihybrid. You cross the dihybrid with the m1m2/m1m2 parent strain. In the offspring, you find 355 m1m2/m1m2 progeny, 345 wild type progeny, 145 m1, and 155 m2 mutant progeny. Are these genes linked? If so, what is the distance between them?
Yes, they are linked, but there's not enough information to determine the distance
Yes, they are linked, the distance is 15 centimorgans
No, they are not linked
Yes, they are linked, the distance is 30 centimorgans
Q4) What are the three steps in mRNA processing in eukaryotes?
initiation, elongation, and termination
capping, elongation, and termination
initiation, intron removal, and polyA signaling
5' capping, splicing, and 3' polyadenylation
helix unwinding, DNA synthesis, and nucleosome rebuilding
Explanation / Answer
Ans 4- option D
5' capping, splicing and 3' polyadenylation are the steps involved in mRNA processing in eukaryotes.
First mRNA is synthesized by initiation, elongation and termination steps of transcription and then it is processed by capping the newly formed mRNA, introns are spliced from that mRNA, and finally a poly A is added by polyadenylation. After this the mRNA is ready to be translated.
Initiation, elongation and termination are the steps of transcription and translation not of mRNA processing. Hence this option is incorrect.
Helix unwinding, DNA synthesis and nucleosome rebuilding are steps of DNA replication. Hence this option is incorrect too.
Similarly two other options are also incorrect as they don't have all the three processes included in them.
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