#Question id: 11601
#Unit 6. System Physiology – Plant
Gibberellin is an important plant hormone that regulates
several aspects of plant growth and development. Some statements are given
below in relation to signalling
pathways:
a) The binding of gibberellin (GA) to its receptor leads to
the degradation of the DELLA repressor by the 26S proteasome
b) Gibberellin binds to the GID1 receptor and induces a
conformational change in the N-terminal domain of the receptor, allowing the
receptor to interact with the TVHYNP and DELLA domains of the DELLA repressor
c) The formation of the GID1-repressor complex promotes the
interaction between the repressor and the E3 ubiquitin ligase SCFTIR1 complex,
leading to the ubiquitination and degradation
d) The gibberellin receptor GIBBERELLIN INSENSITIVE DWARF 1
(GID1) also itself function as an F-box protein
Which one of the following is the incorrect statements about GA signalling pathway;
#Question id: 12280
#Unit 10. Ecological Principles
#Question id: 11902
#Unit 6. System Physiology – Plant
A chemiosmotic model
has been proposed to explain
Polar transport , following steps are involve in the transport of auxin
polarly;
a) IAA enters the cell either passively in the undissociated
form (IAAH) or by secondary active cotransport in the anionic form (IAA–)
b) The cell wall is maintained at an acidic pH by the
activity of the plasma membrane H+- ATPase
c) In the cytosol, which has acidic pH, the IAAH form
predominates
d) The anions exit the cell via auxin anion efflux carriers
that are concentrated at the basal ends of each cell in the longitudinal
pathway
Which of the following is the correct statements about the polarly transporting of auxin?
#Question id: 1384
#Unit 4. Cell Communication and Cell Signaling
Mutations that block expression of the E-cadherin gene are thought to be an important step in metastasis. To better understand how loss of E-cadherin contributes to metastasis, scientists created two cell lines that differed in their expression of E-cadherin. One cell line expressed normal E-cadherin, but at 10% of the usual levels. The other cell line expressed normal E-cadherin at the usual levels, and also, at high levels a mutant form that included the cytoplasmic domain but lacked the rest of the protein. Both cell lines exhibited strongly reduced cell adhesion in culture. However, only the cell line with reduced expression of normal E-cadherin metastasized when introduced into mice.
Which of the following hypotheses is most consistent with the observations on cell adhesion and metastasis in these cell lines?
#Question id: 4470
#Unit 3. Fundamental Processes
Most recent experiments suggest that the last of these is at least an important part of the story and that the conformational change causes the elongating complex to stall, with dissociation following more slowly- this conformational change caused by,