#Question id: 15169
#Unit 2. Cellular Organization
#Question id: 4508
#Unit 3. Fundamental Processes
Statement: In the case of group II introns, the chemistry of splicing and the RNA intermediates produced are the same as those for nuclear pre-mRNA.
Explanations: I. The intron uses an A residue within the branch site to attack the phosphodiester bond at the boundary between its 5’ end and the end of the 5’ exon-that is, at the 5’ splice site. This reaction produces the branched lariat.
II. A second reaction in which the newly freed 3’ -OH of the exon attacks the 3’splice site, releasing the intron as a lariat and fusing the 3’ and 5’ exons.
#Question id: 14979
#Unit 2. Cellular Organization
#Question id: 3619
#Unit 8. Inheritance Biology
Alleles that are both expressed in a heterozygote are
#Question id: 26787
#Unit 8. Inheritance Biology
In the S phase of meiotic interphase, each chromosome replicates, producing two copies of each allele, one on each chromatid, the homologous chromosomes segregation takes place in__
Which of the following statements is correct about the segregation of chromosomes?
a.If no crossing over has taken place, the two chromatids of each chromosome segregate in anaphase II and are identical
b. If crossing over has taken place, the two chromatids are no longer identical, and the different alleles segregate in anaphase II
c. If no crossing over has taken place, the two chromatids of each chromosome segregate in anaphase I and are identical