The early pioneers of microscopy opened a window into the invisible world of microorganisms. In 1830, Joseph Jackson Lister created an essentially modern light microscope. The 20th century saw the development of microscopes that leveraged nonvisible light, such as fluorescence microscopy that uses an ultraviolet light source and electron microscopy that uses short-wavelength electron beams. These advances significantly improved magnification, image resolution, and contrast. By comparison, the...

Aseptic techniques prevent contamination, ensure experimental accuracy, and protect researchers and microbial cultures. These techniques are essential in clinical, industrial, and research settings where sterility is required.Maintaining Sterility in Laboratory PracticesScientists maintain sterility by sterilizing tools with heat or chemicals, disinfecting work surfaces, and handling cultures in controlled environments. Working near an open flame or within a laminar flow hood reduces the risk...

Microtubules are the thickest cytoskeletal filaments with a diameter of 25 nm. In prokaryotic organisms, microtubules are commonly found in locomotory appendages like cilia and flagella. In eukaryotic cells, microtubules form specialized extensions for moving fluid over the surface, like those found in cells lining the intestine.
Microtubules have two structurally similar globular protein subunits: α and β tubulins. In the cytosol, the α and β tubulins form a heterodimer....

There are three types of cytoskeletal structures in eukaryotic cells—microfilaments, intermediate filaments, and microtubules. With a diameter of about 25 nm, microtubules are the thickest of these fibers. Microtubules carry out a variety of functions that include cell structure and support, transport of organelles, cell motility (movement), and the separation of chromosomes during cell division.

Research is what makes the difference between facts and opinions. Facts are observable realities, and opinions are personal judgments, conclusions, or attitudes that may or may not be accurate. In the scientific community, facts can be established only using evidence collected through empirical research.

MicroRNA (miRNA) are short, regulatory RNA transcribed from introns—non-coding regions of a gene—or intergenic regions—stretches of DNA present between genes. Several processing steps are required to form biologically active, mature miRNA. The initial transcript, called primary miRNA (pri-mRNA), base-pairs with itself forming a stem-loop structure. Within the nucleus, an endonuclease enzyme, called Drosha, shortens the stem-loop structure into hairpin-shaped pre-miRNA. After...