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Photosynthesis (/ ˌfoʊtəˈsɪnθəsɪs / FOH-tə-SINTH-ə-sis) [ 1 ] is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabolism.
One cell is responsible for drilling down through the integuments, and creating a conduit for the two sperm cells to flow down. The megagametophyte has just seven cells; of these, one fuses with a sperm cell, forming the nucleus of the egg itself, and another joins with the other sperm, and dedicates itself to forming a nutrient-rich endosperm ...
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms. This number, along with the visual appearance of the chromosome, is known as the karyotype, [1][2][3] and can be found by looking at the chromosomes through a microscope.
Flowers produce two kinds of reproductive cells. Microspores, which divide to become pollen grains, are the male cells; they are borne in the stamens. [57] The female cells, megaspores, divide to become the egg cell. They are contained in the ovule and enclosed in the carpel; one or more carpels form the pistil. [57]
In eukaryotes (i.e., animal, plant, fungal, and protist cells), there are two distinct types of cell division: mitosis and meiosis. [58] Mitosis is part of the cell cycle, in which replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the total number of chromosomes is maintained.
Eukaryotes are organisms that range from microscopic single cells, such as picozoans under 3 micrometres across, [6] to animals like the blue whale, weighing up to 190 tonnes and measuring up to 33.6 metres (110 ft) long, [7] or plants like the coast redwood, up to 120 metres (390 ft) tall. [8]
Anatomical terminology. [ edit on Wikidata] Gap junctions are membrane channels between adjacent cells that allow the direct exchange of cytoplasmic substances. [ 1 ] Substances exchanged include small molecules, substrates, and metabolites. [ 1 ] Gap junctions were first described as close appositions as other tight junctions, but following ...
Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus, and, in plants and algae, the DNA also is found in plastids, such as chloroplasts. [3] Human mitochondrial DNA was the first significant part of the human genome to be sequenced. [4] This sequencing revealed that human mtDNA ...