Which statement best describes the distinction between the purposes of the two RNAi pathways within the eukaryotic cell?

#Question id: 7309

#Unit 5. Developmental Biology

Following statements are regarding to the molecular basis of the coincidence model in Arabidopsis.

A. In Arabidopsis under short days, there is little overlap between CO mRNA expression and daylight.

B. CO protein does not accumulate to sufficient levels in the phloem to promote the expression of the transmissible floral stimulus and the plant remains vegetative.

C. Under long days, the peak of CO mRNA abundance (at hours 12 through 16) overlaps with daylight (sensed by phyA and cryptochrome [cry]), allowing CO protein to accumulate.

D. CO activates FLC mRNA expression in the phloem, which causes flowering when the FT protein is translocated to the apical meristem.

Which of the following is incorrect?

#Question id: 7308

#Unit 5. Developmental Biology

In Arabidopsis thaliana, the transition to flowering involves multiple factors, pathways and meristem identity genes. Following statements regarding to the mechanism and function of meristem identity genes.

 A. FT mRNA is expressed in companion cells of the leaf vein in response to multiple signals, including day length, light quality, and temperature.

 B. The FT–FD complex activates AP1 in the inflorescence meristem and SOC1 in the floral meristem, which triggers LFY gene expression.

 C. LFY and AP1 trigger expression of the floral homeotic genes.

 D. FLC acts as a negative regulator of SOC1 in the meristem and as a negative regulator of FT in the leaves.

 Which of the following is incorrect?

#Question id: 7306

#Unit 5. Developmental Biology

A plant scientist was hired by a greenhouse operator to devise a way to force iris plants to bloom in the short days of winter. Iris normally blooms as a long-day (short-night) plant. Which of the following has the best chance of creating iris blooms in winter?

#Question id: 7304

#Unit 5. Developmental Biology

Which one of the following will be observed when auxin to cytokinin ratio is increased in the culture medium during organogenesis from tobacco pith callus?

#Question id: 7303

#Unit 5. Developmental Biology

The ‘quartet model’ explains how the protein products of the ABCE-function genes might interact to control floral organ identity. Following statements are based on this model. Which one of them is incorrect?

#Question id: 7302

#Unit 5. Developmental Biology

Match the following level of microRNAs in Arabidopsis (Column II and III) with their Phases (Column I)

Which of the following combination is correct?