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The DNA is replicated and a membrane wall known as a spore septum begins to form between it and the rest of the cell. The plasma membrane of the cell surrounds this wall and pinches off to leave a double membrane around the DNA, and the developing structure is now known as a forespore. Calcium dipicolinate, the calcium salt of dipicolinic acid ...
The term sporogenesis can also refer to endospore formation in bacteria, which allows the cells to survive unfavorable conditions. Endospores are not reproductive structures and their formation does not require cell fusion or division. Instead, they form through the production of an encapsulating spore coat within the spore-forming cell.
This cycle is known as alternation of generations. The spores of seed plants are produced internally, and the megaspores (formed within the ovules) and the microspores are involved in the formation of more complex structures that form the dispersal units, the seeds and pollen grains.
The wrong decision can be catastrophic: a vegetative cell will die if the conditions are too harsh, while bacteria forming spores in an environment which is conducive to vegetative growth will be out competed. [3] In short, initiation of sporulation is a very tightly regulated network with numerous checkpoints for efficient control. [citation ...
Zoospores may possess one or more distinct types of flagella - tinsel or "decorated", and whiplash, in various combinations. Tinsellated (straminipilous [3]) flagella have lateral filaments known as mastigonemes perpendicular to their main axis, which allow for more surface area, and disturbance of the medium, giving them the property of a rudder, that is, used for steering.
It can be composed of a single cell or can be multicellular. Virtually all plants , fungi , and many other groups form sporangia at some point in their life cycle . Sporangia can produce spores by mitosis , but in land plants and many fungi, sporangia produce genetically distinct haploid spores by meiosis .
Importantly, encystment is a process observed to precede cell division, [8] while the formation of an endospore involves non-reproductive cellular division. The study of the encystment process was mostly confined to the 1970s and '80s, resulting in the lack of understanding of genetic mechanisms and additional defining characteristics, though ...
A basidium usually bears four sexual spores called basidiospores. Occasionally the number may be two or even eight. Each reproductive spore is produced at the tip of a narrow prong or horn called a sterigma (pl. sterigmata), and is forcefully expelled at full growth. The word basidium literally means "little pedestal". This is the way the ...