Mechano-transduction is the reciprocal interconversion of a mechanical force—or stimulus—and biochemical processes. These interconversions underlie a variety of biological activities, such as signaling, regulated gene expression, cell proliferation, cell migration, and interactions among cells and between cells and the ECM. Mechano-transduction in the context of cell-cell and cell-ECM interactions usually involves a cell-surface CAM or adhesion receptor that transmits mechanical force or biochemical information across the plasma membrane and one or more intracellular or extracellular mechano-sensors that respond to the mechanical stimulus by changing shape and activity. In Hypothetical model of the partial unfolding of a fibronectin type III, when that protein is subjected to mechanical force, following observations are-

A. Mechanical force generated within the cell by actin movement and transduce via multiple integrin adhesion receptors bound to the extracellular dimeric fibronectin can partially unfold the fibronectin.

B. The unfolding is thought to expose a putative, previously hidden binding site on fibronectin that has the potential to form β sheets with other fibronectin molecules, recruiting them to form fibronectin fibrils, and thus helping assemble the ECM.

According to observations which of the following protein act as mechano-sensor and mechano-transducer respectively?

#Question id: 11599

#Unit 6. System Physiology – Plant

Where the highest levels of gibberellins are found?

#Question id: 11600

#Unit 6. System Physiology – Plant

The first plant gibberellin to be identified was___

#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 SCF^TIR1 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: 11602

#Unit 6. System Physiology – Plant

The concentration of gibberellins in plants is very low usually 1–10 parts per billion for the _____A_________ in _______B________ and up to 1 part per million of total gibberellins in ______C________.

#Question id: 11603

#Unit 6. System Physiology – Plant

Several important role promotes GA in the plant except____

#Question id: 11604

#Unit 6. System Physiology – Plant

What will be the effect of exogenous gibberellin in plant?

a) extreme stem elongation in dwarf plants

b) Increases  in stem thickness

c) decrease in leaf size

d) decreases in stem thickness

e) Increases in leaf size

f) pale green color of the leaves