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TLS Online TPP Program

#Question id: 1262

Although MAP kinase is often activated in multicellular animals by RTKs or cytokine receptors, signaling from other receptors can activate MAP kinase in other eukaryotic cells. we consider the mating pathway in the yeast S. cerevisiae, a well-studied example of a MAP kinase cascade linked to G protein–coupled receptors (GPCRs). Which of the following statement is incorrect?

#Unit 4. Cell Communication and Cell Signaling

  1. An a haploid cell secretes the a mating factor and has GPCRs for the α factor on its cell surface; an α cell secretes the α factor and has GPCRs for the a factor. Thus each type of cell recognizes the mating factor produced by the opposite type.

  2. Ligand binding and dissociation of the G protein subunits, the membrane-tethered Gβγ subunit binds the Ste5 scaffold to the plasma membrane.

  3. Gβγ also activates Cdc24, a GAP for the Ras-like protein Cdc42; the active, GTP-bound Cdc42, in turn, binds to and activates the Ste20 kinase.

  4. Ste20 then phosphorylates and activates Ste11, which is analogous to Raf and other mammalian MEK kinase (MEKK) proteins. Ste20 thus serves as a MAPKKK kinase.

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TLS Online TPP Program

#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?
TLS Online TPP Program

#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?
TLS Online TPP Program

#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?
TLS Online TPP Program

#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?
TLS Online TPP Program

#Question id: 7302

#Unit 5. Developmental Biology

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

   Phases (Column I)

 microRNAs (Column II)

Level of microRNAs (Column III)

A. Juvenile vegetative phase

i. miR156

a. Low

B. Adult vegetative phase

ii. miR172

b. High

C. Reproductive phase

 

 

Which of the following combination is correct?
TLS Online TPP Program

#Question id: 7301

#Unit 5. Developmental Biology

An Rajasthani hunter was worried about being attacked by grizzly tigers, so he left the lights in his cabin on all the time. Plants near the cabin flowered a month early. Which of the following best explains this?