Search results
Results from the WOW.Com Content Network
Ultrastructure (or ultra-structure) is the architecture of cells and biomaterials that is visible at higher magnifications than found on a standard optical light microscope. This traditionally meant the resolution and magnification range of a conventional transmission electron microscope (TEM) when viewing biological specimens such as cells ...
A section of a cell of Bacillus subtilis, taken with a Tecnai T-12 TEM. The scale bar is 200 nm. TEM samples of biological tissues need high atomic number stains to enhance contrast. The stain absorbs the beam electrons or scatters part of the electron beam which otherwise is projected onto the imaging system.
Cytochemistry is a science of localizing chemical components of cells and cell organelles on thin histological sections by using several techniques like enzyme localization, micro-incineration, micro-spectrophotometry, radioautography, cryo-electron microscopy, X-ray microanalysis by energy-dispersive X-ray spectroscopy, immunohistochemistry ...
The Davson-Danielli model threw new light on the understanding of cell membranes, by stressing the important role played by proteins in biological membranes. By the 1950s, cell biologists verified the existence of plasma membranes through the use of electron microscopy (which accounted for higher resolutions).
The cell on the left is going through mitosis and its chromosomes have condensed. Cell nucleus: A cell's information center, the cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis (transcription) occur.
It contains a single nucleus and a basal body. The nucleus is about 4 μm in diameter. The cell membrane is covered with scales and is highly flexible. The external scales are boat shaped, each measuring 150 nm long and 70 nm wide. [1] Ultrastructure of Idionectes vortex. (A) Whole cell showing with several pseudopodia that project leptopodia.
David Hibberd's comparison of the ultrastructural identities of a typical chrysophyte and a typical haptophyte. Ultrastructural identity is a concept in biology.It asserts that evolutionary lineages of eukaryotes in general and protists in particular can be distinguished by complements and arrangements of cellular organelles.
In 1903, Nikolai K. Koltsov proposed that the shape of cells was determined by a network of tubules that he termed the cytoskeleton. The concept of a protein mosaic that dynamically coordinated cytoplasmic biochemistry was proposed by Rudolph Peters in 1929 [12] while the term (cytosquelette, in French) was first introduced by French embryologist Paul Wintrebert in 1931.