T cellT cells are one of the important types of white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell surface. T cells are born from hematopoietic stem cells, found in the bone marrow. Developing T cells then migrate to the thymus gland to develop (or mature). T cells derive their name from the thymus. After migration to the thymus, the precursor cells mature into several distinct types of T cells.
MicroorganismA microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from sixth century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation.
HolozoaHolozoa is a group of organisms that includes animals and their closest single-celled (protist) relatives, but excludes fungi and all other organisms. It is a monophyletic group or clade, a lineage consisting of all descendants of a common ancestor. Among these descendants, the protists are of high interest because of their close relationship to animals: in the search for the genes responsible for animal multicellularity within these protists, they help elucidate the nature of the unicellular ancestor of animals.
Anoxygenic photosynthesisAnoxygenic photosynthesis is a special form of photosynthesis used by some bacteria and archaea, which differs from the better known oxygenic photosynthesis in plants in the reductant used (e.g. hydrogen sulfide instead of water) and the byproduct generated (e.g. elemental sulfur instead of molecular oxygen). Several groups of bacteria can conduct anoxygenic photosynthesis: green sulfur bacteria (GSB), red and green filamentous phototrophs (FAPs e.g. Chloroflexia), purple bacteria, acidobacteriota, and heliobacteria.
GlycosomeThe glycosome is a membrane-enclosed organelle that contains the glycolytic enzymes. The term was first used by Scott and Still in 1968 after they realized that the glycogen in the cell was not static but rather a dynamic molecule. It is found in a few species of protozoa including the Kinetoplastida which include the suborders Trypanosomatida and Bodonina, most notably in the human pathogenic trypanosomes, which can cause sleeping sickness, Chagas's disease, and leishmaniasis.
IsogamyIsogamy is a form of sexual reproduction that involves gametes of the same morphology (indistinguishable in shape and size), found in most unicellular eukaryotes. Because both gametes look alike, they generally cannot be classified as male or female. Instead, organisms undergoing isogamy are said to have different mating types, most commonly noted as "+" and "−" strains. The literal meaning of isogamy is "equal marriage" which refers to equal contribution of resources by both gametes to a zygote.
Parakaryon myojinensisParakaryon myojinensis, also known as the Myojin parakaryote, is a highly unusual species of single-celled organism known only from a single specimen, described in 2012. It has features of both prokaryotes and eukaryotes but is apparently distinct from either group, making it unique among organisms so far discovered. It is the sole species in the genus Parakaryon. The generic name Parakaryon comes from Greek παρά (pará, "beside") and κάρυον (káryon, "kernel", "nucleus"), and reflects its distinction from eukaryotes and prokaryotes.
Cell physiologyCell physiology is the biological study of the activities that take place in a cell to keep it alive. The term physiology refers to normal functions in a living organism. Animal cells, plant cells and microorganism cells show similarities in their functions even though they vary in structure. There are two types of cells: prokaryotes and eukaryotes. Prokaryotes were the first of the two to develop and do not have a self-contained nucleus. Their mechanisms are simpler than later-evolved eukaryotes, which contain a nucleus that envelops the cell's DNA and some organelles.
