Which gas was least abundant in Earthʹs early atmosphere, prior to 2 billion years ago?

#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: 7310

#Unit 5. Developmental Biology

Which statement best describes the mechanism for circadian rhythm?

#Question id: 7311

#Unit 5. Developmental Biology

According to the ABC model of flower development in Arabidopsis, three classes of organ identity genes— designated A, B, and C— are required to specify the identity of floral organs in each whorl of a flower. If wild type Arabidopsis were transformed with a chimeric gene composed of a C class promoter fused to a B class coding sequence, which of the following arrangements   (outer to inner) would be predicted?

#Question id: 7312

#Unit 5. Developmental Biology

Following statements regarding to the classes of genes that regulate floral development:

A.  Floral organ identity genes directly control floral identity. The proteins encoded by these genes are transcription factors that likely control the expression of other genes whose products are involved in the formation and/or function of floral organs.

B.  Cadastral genes act as spatial regulators of the floral organ identity genes by setting boundaries for their expression.

C.   Meristem identity genes are necessary for the initial induction of the organ identity genes. These genes are the positive regulators of floral organ identity.

D.  Cadastral genes act as negative regulators of the floral organ identity genes by inhibits their expression.

E.   Meristem identity genes are the negative regulators of floral organ identity genes.

Which of the above statements are true?

#Question id: 7313

#Unit 5. Developmental Biology

Which of the following statement incorrect about the meristem?

#Question id: 7314

#Unit 5. Developmental Biology

With reference to plant flowering pattern; match the terms of Column I with the most appropriate term of Column II. (Se-Sepal; Ca-Carpel; St-stamen; Pe-Petal)