سوال ۲۳ کنکور ارشد مهندسی مکانیک ۱۴۰۰

PART C: Reading Comprehension

PASSAGE 2 (excerpt):

Any assemblage of building blocks - whether animate or inanimate, whether a rock or a human being - needs physical forces to hold itself together. Without the attractive and repulsive forces between atoms, any object we know will just crumble to a nondescript pile of matter. Similarly, without the mechanical interactions between its cells, any multicellular organism would lose its form, functions, and any of the attributes we usually recognize it for. There is no denying that physical forces and mechanics are of paramount importance in shaping biological entities. In many cases, the existence of forces acting directly on molecules or cells is required in order to trigger the correct biological response. This is in essence what mechanotransduction is: the ability to alter biological outcomes through mechanical forces.

One of the most interesting features of mechanotransduction is that it reveals a new layer of modulation of the interactions between molecules, and a potential global guiding principle for organizing biological entities from molecules to cells. At the same time, as new technological advances have enabled us to measure and apply forces on cells and molecules (optical tweezers, magnetic tweezers, and lithography to name a few examples), we have come to realize how pervasive the role of physical forces is. Mehanotransduction, defined as the modulation of biological fates by physical forces, has been found to occur in all corners of the biological realm and with an extremely rich and diverse set of mechanisms. Some of these mechanisms are very similar across all domains of life, as in the case of the mechanosensitive channels that allow physical stimuli on or across cell membranes to control the flow of molecules across these membranes: flow that can in turn release osmotic pressure or trigger another signaling pathway.

Which of the following best describes mechanotransduction?