How is methylation of DNA maintained following DNA replication?
What will be an ideal response?
Ans: Before replication, DNA is found in a fully methylated state, meaning that on both strands cytosines of CpG doublets are methylated. After replication, the template strand is methylated but the newly synthesized strand is not; the site is said to be hemimethylated. A maintenance methylase enzyme recognizes hemimethylated sites and fully methylates them.
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The skin infection streptothrichosis is caused by members of the genus ________.
A. Streptomyces B. Streptococcus C. Dermatophilus D. Propionibacterium
Suppose you are culturing tobacco in a petri dish at a 10:1 ratio of auxin to cytokinin. To promote only
shoot development you would
a. increase the cytokinin ratio b. increase the auxin ratio c. reduce the auxin level significantly and increase the cytokinin level slightly d. grow the tobacco in the dark e. grow the tobacco in the light
Bird song
a. has to be heard before a bird can sing it. b. is learned during early life. c. is specific for each bird species. d. has a genetic component. e. includes all of these.
Genes are
a. located on chromosomes. b. inherited in the same way as chromosomes. c. arranged in linear sequence on chromosomes. d. assorted independently during meiosis. e. all of these.