Understanding operating principles and processivity of molecular motors

Motor proteins, sometimes referred to as mechanoenzymes, are a group of proteins that maintain a large part of intracellular motion. Being enzymes, they undergo chemical reactions leading to energy conversion and changes of their conformation. Being mechanodevices, they use the chemical energy to perform mechanical work, leading to the phenomena of motion. Over the past 20 years a series of novel experiments (e.g. single molecule observations) has been performed to gain the deeper knowledge about chemical states of molecular motors as well as their dynamics in the presence or absence of an external force. At the same time, many theoretical models have been proposed, offering various insights into the nano-world dynamics. They can be divided into three main categories: mechanochemical models, ratchet models and molecular dynamics simulations. We demonstrate that by combining those complementary approaches a deeper understanding of the dynamics and chemistry of the motor proteins can be achieved. As a working example, we choose kinesin — a motor protein responsible for directed transport of organelles and vesicles along microtubule tracts

Entropy production and collective phenomena in biological channel gating

We investigate gating kinetics of biological channels influenced by conformational changes within the membrane proteins forming the module, and subject to a coupling with other similar units. By introducing elements of stochastic thermodynamics, we analyze the information flow and associated entropy production during gating cycle of a single channel. In the second part of this paper, synchronized kinetics of multiple units of that type is analyzed in terms of Kuramoto’s theory

Digital university : a study of students’ experiences and expectations in the post-COVID era

In 2020, the education process at universities started to be redefined, parting with the traditional face-to-face form. The article presents the conclusions of exploratory study conducted at the Jagiellonian University in Kraków (Poland) on the students’ experiences of remote education as well as their expectations for the future. The study was conducted in the form of an online survey addressed to the entire population of science recipients at the Jagiellonian University, around 800 respondents completed the questionnaire. The obtained results show that most students rate remote education relatively high, although there are statistically significant differences in specific questions (e.g., theoretical classes are more suitable for online learning than practical classes). The authors paid special attention to the differences in the attitudes of students depending on their characteristics, the approach to remote education differs, in particular, depending on the gender and field of study. Students of social and humanist faculties view remote education most positively, and science students opinions are mostly negative. It has also been observed that some students are uncritically satisfied with most aspects of distance learning (the so-called "Tiggers"), while others are strong supporters of face-to-face education, reluctant to accept any changes (so-called "Eeyores"), so regardless of the scope of pro-quality activities undertaken, both criticism and praise of remote education can be expected. The obtained results open the field for further studies that would allow to confirm the covariance of multidimensional characteristics of students and their attitudes towards the digital university, and on the other hand would allow planning activities aimed at different and perhaps mutually contradictory expectations of the recipients of education

"Cargo-mooring" as an operating principle for molecular motors

Navigating through an ever-changing and unsteady environment, and utilizing chemical energy, molecular motors transport the cell׳s crucial components, such as organelles and vesicles filled with neurotransmitter. They generate force and pull cargo, as they literally walk along the polymeric tracks, e.g. microtubules. What we suggest in this paper is that the motor protein is not really pulling its load. The load is subject to diffusion and the motor may be doing little else than rectifying the fluctuations, i.e. ratcheting the load׳s diffusion. Below we present a detailed model to show how such ratcheting can quantitatively account for observed data. The consequence of such a mechanism is the dependence of the transport׳s speed and efficacy not only on the motor, but also on the cargo (especially its size) and on the environment (i.e. its viscosity and structure). Current experimental works rarely provide this type of information for in vivo studies. We suggest that even small differences between assays can impact the outcome. Our results agree with those obtained in wet laboratories and provide novel insight in a molecular motor׳s functioning