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Structure of a typical animal cell Structure of a typical plant cell. Plants, animals, fungi, slime moulds, protozoa, and algae are all eukaryotic. These cells are about fifteen times wider than a typical prokaryote and can be as much as a thousand times greater in volume.
Like bacteria, plant cells have cell walls, and contain organelles such as chloroplasts in addition to the organelles in other eukaryotes. Chloroplasts produce energy from light by photosynthesis, and were also originally symbiotic bacteria. [59] Unicellular eukaryotes consist of a single cell throughout their life cycle.
Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound organelles. Although the term bacteria traditionally included all prokaryotes, the scientific classification changed after the discovery in the 1990s that prokaryotes consist of two very different groups of organisms that ...
For adherent cells, cell density is normally measured in terms of confluency, the percentage of the growth surface covered by cells. The cells will often have a known range of confluencies for optimal growth, for example a mammalian cell line like HeLa generally prefers confluencies between 10% and 100%, and subculture will normally try to keep ...
Many multicellular organisms produce spores during their biological life cycle in a process called sporogenesis. Exceptions are animals and some protists, which undergo meiosis immediately followed by fertilization. Plants and many algae on the other hand undergo sporic meiosis where meiosis leads to the formation of haploid spores rather than ...
Theoretically, one viable cell can give rise to a colony through replication. However, solitary cells are the exception in nature, and in most cases the progenitor of a colony is a mass of cells deposited together. [1] [2] In addition, many bacteria grow in chains (e.g. Streptococcus) or clumps (e.g., Staphylococcus). Estimation of microbial ...
Microbiology (from Ancient Greek μῑκρος (mīkros) 'small' βίος (bíos) 'life' and -λογία 'study of') is the scientific study of microorganisms, those being of unicellular (single-celled), multicellular (consisting of complex cells), or acellular (lacking cells).
The measurement of an exponential bacterial growth curve in batch culture was traditionally a part of the training of all microbiologists; the basic means requires bacterial enumeration (cell counting) by direct and individual (microscopic, flow cytometry [1]), direct and bulk (biomass), indirect and individual (colony counting), or indirect ...