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Typically, each body segment carries one pair of appendages. An appendage which is modified to assist in feeding is known as a maxilliped or gnathopod. [citation needed] In annelids lateral protrusions from the body are called parapodia. In echinoderms an appendage called a pedicellaria is found. The end of the pedicellaria consists of valves ...
[8] [9] Microtentacles are cell protrusions attached to free-floating cells, associated with the spread of some cancer cells. [10] In prokaryotes such protrusions are known as surface or cell-surface appendages and include flagella, pili, fimbriae, and nanowires. [11] [8] Some archaea possess very complex appendages known as hami. [12]
Genetic fragments such as pseudogenes, regions of DNA that are orthologous to a gene in a related organism, but are no longer active and appear to be undergoing a steady process of degeneration from cumulative mutations support common descent alongside the universal biochemical organization and molecular variance patterns found in all organisms ...
3-The mobile plasmid is nicked and a single strand of DNA is then transferred to the recipient cell. 4-Both cells recircularize their plasmids, synthesize second strands, and reproduce pili; both cells are now viable donors. A pilus (Latin for 'hair'; pl.: pili) is a hair-like cell-surface appendage found on many bacteria and archaea. [1]
A detailed survey of the various nonmotile appendages found in eukaryotes is also necessary. Finally, the study of the origin of all of these systems would benefit greatly from a resolution of the questions surrounding deep phylogeny, as to what are the most deeply branching organisms in each domain, and what are the interrelationships between ...
In Polychaeta, chaetae are found as bundles on the parapodia, paired appendages on the side of the body. [1] The chaetae are epidermal, extracellular structures, and clearly visible in most polychaetes. They are probably the best-studied structures in these animals. [2] Segments bearing chaetae are called chaetigers. [3]
Genetic linkage is the tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction.Two genetic markers that are physically near to each other are unlikely to be separated onto different chromatids during chromosomal crossover, and are therefore said to be more linked than markers that are far apart.
Crossing over also accounts for genetic variation, because due to the swapping of genetic material during crossing over, the chromatids held together by the centromere are no longer identical. So, when the chromosomes go on to meiosis II and separate, some of the daughter cells receive daughter chromosomes with recombined alleles.