The asymmetric cilia of euglenid flagellates
Dye, Kathryn Morris
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Ciliary gliding is a mode of cell locomotion used by a broad range of protists and is thought to be one of the earliest forms of eukaryotic cell motility. Ciliary gliding is the primary form of motility used by the heterotrophic Euglenids which are considered to represent some of the most basal organisms at the root of the eukaryotic radiation. The Euglenid cilium has an inherent asymmetry in that it is comprised of two parts; the paraxial rod (a lattice-like fiber that extends the length of the cilium) and the axoneme with its highly conserved 9+2 arrangement of microtubules and associated motor and structural proteins. Ciliary gliding in Euglenids can be categorized in two ways: those that are pulled along by an anteriorly directed cilium (e.g. ‘pullers’) and those that use the posteriorly directed cilium to move the cell forward (e.g. “pushers”). These studies determined the orientation of the cilium in pushers and pullers, identified the presence of the likely force production machinery in the Euglenids phylogenetically and with microscopy, and investigated the role of microtubule doublet preference in an effort to determine the role ciliary asymmetry plays in ciliary gliding in Euglenids. Students with strong metacognition are positioned to learn more, have better performance, and persist through difficult tasks. There are two divisions of metacognition: metacognitive knowledge, the awareness of our thinking, and metacognitive regulation, how we control our thinking in order to learn. Metacognitive regulation skills include the ability to monitor individual strategies, plan, and evaluate their plan. In this study we investigated these skills in upper-division biology students taking Cell Biology through the analysis of self-evaluation assignments (n=96) and individual interviews (n=14). Analysis of the self-evaluation assignment shows that 94% of the participants showed evidence of utilizing metacognitive regulation skills. The interview data suggests that the curriculum for a biology degree drives the development of metacognitive regulation skills. These students also reported developing the ability to assess the tasks their course work demands, including making distinctions across disciplines. We also found that the ability to monitor individual study strategy effectiveness is not only an important metacognitive regulation skill but may also plays a role in behavior change and stress coping.