Many of the cells and microorganisms which are transparent to visible light, absorb or reflect the much shorter wavelengths of the ultraviolet spectrum.

Many protists also exist as individual amoeboid cells, or take such a form at some point in their life-cycle.

Many types of specialized plasma membranes can separate cell from external environment: apical, basolateral, presynaptic and postsynaptic ones, membranes of flagella, cilia, microvillus, filopodia and lamellipodia, the sarcolemma of muscle cells, as well as specialized myelin and dendritic spine membranes of neurons.

Many green algae, such as the Dasycladales encase their cells in a secreted skeleton of calcium carbonate.

Many plant cells have walls that are strong enough to withstand the osmotic pressure from the difference in solute concentration between the cell interior and distilled water.

Many cells have only a single mitochondrion, whereas others can contain several thousand mitochondria.

Many neurons have only one axon, but this axon may — and usually will — undergo extensive branching, enabling communication with many target cells.

Many of the features found in human ovaries are common to all vertebrates, including the presence of follicular cells, tunica albuginea, and so on.

Many argue that these are not themselves alive in the traditional sense, but these structures exhibit many of the characteristics of cells accepted as living cells:

Many transcription factors, especially some that are proto-oncogenes or tumor suppressors, help regulate the cell cycle and as such determine how large a cell will get and when it can divide into two daughter cells.

Many neurons in the rat and mouse hippocampus respond as place cells: that is, they fire bursts of action potentials when the animal passes through a specific part of its environment.

Many cells can completely undergo interphase without centrioles.

Many cyanobacteria even display the circadian rhythms that were once thought to exist only in eukaryotic cells ( see bacterial circadian rhythms ).

Many cells also possess a calcium ATPase, which can operate at lower intracellular concentrations of calcium and sets the normal or resting concentration of this important second messenger.

Many lichens reproduce asexually, either by vegetative reproduction or through the dispersal of diaspores containing algal and fungal cells.

Many bacteria can be found deep in the mucus, which is continuously secreted by mucus-secreting cells and removed on the luminal side.

Many starfish also possess individual photoreceptor cells across their bodies and are able to respond to light even when their eyespots are covered.

Many cells bind to components of the extracellular matrix.

Many cells possess these receptors, and the binding of an agonist will generally cause a sympathetic ( or sympathomimetic ) response ( e. g. the fight-or-flight response ).

Many forms of cutaneous and mucosal allergy are mediated for a large part by mast cells ; they play a central role in asthma, eczema, itch ( from various causes ) and allergic rhinitis and allergic conjunctivitis.

Many cancer cells are considered ' immortal ' because telomerase activity allows them to divide virtually forever, which is why they can form tumors.

Many pre-invasive lesions in cases of squamous cell carcinoma often regress after long-term reduced exposure of the affected cells and tissues to the original environmental carcinogenic stimulus, such as that seen after long-term abstention from tobacco smoking.

Many are asymmetrical, the cells twisting sideways and then untwisting again prior to division, which often takes place within cysts.

Many of these solutions aim to control the Volatile Sulfur Compound ( VSC )- creating anaerobic bacteria that live in the mouth and excrete substances that lead to bad breath and unpleasant mouth taste.

Many bacteria, however, possess mechanisms ( such as siderophores ) for scavenging iron within environmental niches in the human body, and experimental developments of iron chelators, therefore, aim to reduce iron availability specifically to bacterial pathogens.

Many bacteria, such as Vibrio, are monoflagellated and have a single flagellum at one pole of the cell.

Many instances of endosymbiosis are obligate ; that is, either the endosymbiont or the host cannot survive without the other, such as the gutless marine worms of the genus Riftia, which get nutrition from their endosymbiotic bacteria.

Many bacteria cease production of the enzyme in the presence of oxygen.

Many of the postures massage the lymphatic system and aid in lymphatic drainage, assisting to eliminate infection, bacteria, and toxins.

Many of these symptoms occur when bacteria that normally inhabit the thick mucus grow out of control and cause pneumonia.

Many Fabaceae host bacteria in their roots within structures called root nodules.

Many plant fibers, for example, are indigestible to many herbivores leaving grazer community food webs more nutrient limited than detrital food webs where bacteria are able to access and release the nutrient and energy stores.

Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population.

Many bacterial species, including E. coli, an enteric bacterium and model organism for Gram-negative bacteria, produce AI-2.

Many lichens produce secondary compounds, including pigments that reduce harmful amounts of sunlight and powerful toxins that reduce herbivory or kill bacteria.

Many of the bacteria in the digestive tract, collectively referred to as the gut flora, are able to break down certain nutrients such as carbohydrates that humans otherwise could not digest.

Many biocides are synthetic, but a class of natural biocides, derived from e. g. bacteria and plants, includes brassica oleracea, brassica oleracea gemmifera, and clostridium botulinum bacteria.

Many bacteria can survive adverse conditions such as temperature, desiccation, and antibiotics by endospores, cysts, conidia or states of reduced metabolic activity lacking specialized cellular structures.

Many types of bacteria can cause necrotizing fasciitis ( e. g., Group A streptococcus ( Streptococcus pyogenes ), Staphylococcus aureus, Clostridium perfringens, Bacteroides fragilis, Aeromonas hydrophila ).

Many schools do not allow chewing gum because students often dispose of it inappropriately, or because it might carry diseases / bacteria from other students and is distracting to others in the classroom by smacking.

Many autotrophic bacteria and archaea fix carbon via the reductive acetyl CoA pathway, the 3-hydroxypropionate cycle, or the reverse Krebs cycle.

Many human cell types express them, as do certain bacteria and many other organisms, such as plants for which it is essential for the water transport system.

Many species of bacteria are subject to lysis by the enzyme lysozyme, found in animal saliva, egg white, and other secretions.

Many healthy breastfeeding women wishing to donate breast milk have potentially pathogenic bacteria in their milk but have no symptoms of mastitis.

Many times the groundwater is recycled to allow for continuously flowing water and enhanced bacteria population growth.