The qualitative graph below shows the molecular changes accompanying vernalization in the flowering plant Arabidopsis thaliana. Indicate which curve (A to D) in the graph better represents the temporal changes in each of the following variables. Your answer would be a four-letter string composed of letters A to D only, with each letter used once, e.g. BACD.

( ) Level of Coolair noncoding RNA
( ) Level of Flowering locus C (FlC) gene product (transcriptional repressor)
( ) Level of Flowering locus T (Ft) gene product (transcriptional activator)
( ) Level of repressive chromatin marks at the FlC locus

Question

The qualitative graph below shows the molecular changes accompanying vernalization in the flowering plant Arabidopsis thaliana. Indicate which curve (A to D) in the graph better represents the temporal changes in each of the following variables. Your answer would be a four-letter string composed of letters A to D only, with each letter used once, e.g. BACD.
  
( )	Level of Coolair noncoding RNA
( )	Level of Flowering locus C (FlC) gene product (transcriptional repressor)
( )	Level of Flowering locus T (Ft) gene product (transcriptional activator)
( )	Level of repressive chromatin marks at the FlC locus

Quizplus · Accepted Answer

As Coolair levels (curve B) peak during vernalization, closed chromatin structures (curve C) are induced at the FlC locus, gradually shutting off FlC expression (curve A). This persisting change in turn allows flowering genes of the Ft locus to be expressed under the right conditions in the spring (curve D).

The Qualitative Graph Below Shows the Molecular Changes Accompanying Vernalization