Answer:
<u>Biofilms are</u> defined as complex communities of microorganisms that grow embedded in a self-produced polymeric organic matrix and adhered to a living or inert surface, and that can present a single microbial species or a range of different species
Explanation:
The bacteria that form the biofilm are in what is called sessile form, exhibiting a phenotype different from those of the same cells in unicellular or free form (planktonic form) with respect to the growth rate and gene transcription (Donlan, 2002 ).
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The formation</u> of biofilms is an adaptive strategy of microorganisms, since growth in biofilm offers four important advantages: (I) protects microorganisms from the action of adverse agents, (II) increases the availability of nutrients for their growth, (III) facilitates the use of water, reducing the possibility of dehydration and (IV) enables the transfer of genetic material (DNA). All of these circumstances can increase your survival capabilities. As a consequence, <u>the usual methods of disinfection or the use of antibiotics are often ineffective against biofilm bacteria</u>.
In addition to the risk of contamination, the development of biofilms can interfere with different processes and cause damage to the equipment. In drinking water systems the formation of biofilms can obstruct the pipes reducing their speed and transport capacity causing an increase in energy consumption. The formation of biofilm in heat exchangers and cooling towers can reduce heat transfer and as a consequence its efficiency in the process. The formation of persistent biofilms on metal surfaces can cause corrosion due to acid production by bacteria.
The correct answer is D: I and II only.
Viruses have protein capsids, which protect their genetic material. This capsid sometimes is covered by viral envelopes which have glycoproteins on their surface. Glycoproteins help in the process of binding to the host cell and infecting it. In this example, virus III has the structure of a bacteriophage and it does not seem to have glycoproteins. Bacteriophages use their tail fibers to attach to the bacterial host and inject their genetic material. On the contrary, viruses I and II have glycoproteins sticking out of their envelopes.
Wavelength light source is part of the control group for William’s experiment
<u>Explanation:</u>
Sir William wanted to conduct an experiment to observe how much heat passed through different colour filters of the sunlight. He directed sunlight to pass through the prism and observed vibgyor and measured the temperature. He found that the temperature increased from violet to red.
Then he was inquisitive to find the temperature beyond the red ray. That’s when he found the infrared rays which had higher temperature that was not to be seen through naked eyes. He performed experiments using the light source and found that the wavelength of light are not refracted in a particular pattern.
Ensory cells<span> are </span>cells<span> which detect information (such as sounds, light, touch, smell, taste, and temperature) through receptors on their surface. This information travels through nerves from the </span>sensory cells<span> to the brain.</span>
