Question

C. How do RecA and RecBCD function to promote recombination? D. Endonuclease activity of RecBCD is greater in the 3'-5' strand, rather than the 5'-3' strand. Describe how this affects strand invasion, branch migration and resolution. E. How is recombination initiated during meiosis in eukaryotes? F. What is the connection between nonhomologous end joining repair and canc

Answer 1

C;-- ans; Beginning at a DNA double strand end, it unwinds DNA and, at a special nucleotide sequence called chi, makes a new "3" end at which it begins loading multiple RecA protein molecules on to the single stranded DNA generated by continued unwinding.

D ; ans;. Strand invasion is the process in which the nucleoprotein complex(composed of the broken single strand DNA and the recombinase) searches and identifies a region of homology in intact duplex DNA. Branch migration is the process in which base pairs on homologous DNA strands are consecutively exchanged at a holiday junction, moving the branch point up or down the DNA sequence.

E ; ans; . During meiosis in eukaryotes, genetic recombination involves the pairing of homologous chromosomes. This may be followed by information transfer between the chromosomes. In meiosis, no sister homologous chromosomes pair with each other so that recombination characteristically occur between no sister homologous.recombination is a process by which pieces of DNA are broken and recombined to produce new combinations of alleles. In eukaryotic cells, which are cells with nucleus and organelles.

F ans; Non homologous end joining(NHEJ)is a pathway that repairs double strand breaks in DNA. NHEJ is referred to as non homologous because the break ends are directly ligated without the need for a homologous template, in contrast to homology directed repair, which requires a homologous sequence to guide repair.