Answer:
In 1884, Hans Christian Gram described a method of staining bacterial cells while not staining surrounding animal tissues. However, he thought that the staining method he developed was faulty because not all bacteria stained. ... Not all bacteria stained because some have walls that prevents the staining.
Answer:
a. the virus must be able to cross-link red blood cells directly.
Explanation:
Viral hemagglutination assay is a method which is used for the quantification of the relative concentration of the viruses.
The principle on which the hemagglutination assay works is as follows:
- There are sialic acid receptors present on the surface of the red blood cells which will bind to the haemagglutinin glycoprotein present on the surface of the viral particle.
- Due to the binding of the sialic acid receptors with haemagglutinin particle there will be cross-linking of the red blood cells by the viral particles and a lattice formation will take place.
- The lattice will remain suspended in the solution however if the concentration of the virus particles will be less, the lattice will settle down in the well.
Thus, this method allows knowing the relative concentration of the virus.
<em>Due to its basic principle of cross-linking this method works well for only a few viruses such as influenza virus. </em>
Answer:
cold with high salt content
Answer:
1.In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species? are related and gradually change over time.
2.Survival of the fittest is a simple way of describing how evolution (the process by which gradual genetic change occurs over time to a group of living things) works. It describes the mechanism of natural selection by explaining how the best-adapted individuals are better suited to their environment.
