Answer:
Cells in a large multicellular organism communicate with each other by chemical signals. These signals are passed from one cell to another. To receive and respond to a chemical signal, a cell must have a <u><em>receptor</em></u> for that chemical.
Explanation:
To generate a physiological response, all cells in the body have special proteins called receptors. These receptors are involved in detecting a chemical signal and generating a response. The receptors are specific for different kind of chemical signals. For example, a dopamine receptor will bind a dopamine molecule whereas an insulin receptor will be able to bind an insulin molecule. Apart from chemical signals, some cells might also respond to mechanical signals.
<span>Proteins secreted by epithelial cells. The basement membrane forms as a thin protein fibre membrane with mucopolysaccharides. It separates an epithelium from underlying tissue. Its main function is to anchor epithelium to dermis underneath. The membrane consists of different extracellular matrix structural proteins.</span>
The purpose of the replication bubble is that it forms where replication is taking place (option A).
<h3>What is replication?</h3>
Replication is the process of producing replicas or duplicate of DNA or RNA molecules.
DNA replication is a very important process that occurs prior to cell division. During replication, the double stranded DNA is separated into two single strands.
Each copy called the leading and lagging strand becomes the template for the synthesis of new DNA strands.
However, a structure called replication bubble is a formed during the separation of two DNA strands by the helicase enzymes.
Therefore, the purpose of the replication bubble is that it forms where replication is taking place.
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The nitrogen cycle is completed with the process of Denitrification
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Explanation:</u></h3>
Denitrification finishes the nitrogen cycle by transforming nitrate behind to vaporous nitrogen. Denitrifying bacteria are the doers of this method. These bacteria utilize nitrate alternately of oxygen while gaining energy, delivering nitrogen gas into the environment.
Denitrification relies on microbial action to crumble freely nitrogen-containing components. Bacilli absorb nitrate to generate energy, but in the method, denitrification transpires and nitrogen is diminished. Denitrification is an anaerobic means, transpiring chiefly in soils and deposits and anoxic zones in ponds and shores.
