Question

1. Describe Koch's postulates and how they pertain to germ theory.

2. Explain how host behavior can impact susceptibility to disease.

3. In your opinion, which is the most important characteristic of microscopy when viewing a microbe, magnification, resolution, or contrast? Explain.

Answer 1

1. Robert Koch in 1884, proposed 4 postlates about the relation between pathogen and a disease. He explained the criteria for accepting a microbe as a pathogen. The postlates includes;
• The organism must be abubdant in a person suffering from a disease and should not present in a healthy person. It must be present in all cases of infection.
• It can be isolated from the diseased body and can be cultured in pure culture.
• The pathogen in culture can make infection to a healthy person or organism.
• The organism must be isolated from the deceaced experimental organism and it should be identical to the inoculated organism.

In the same period, Louis Pasteur in 1861 proposed that certain diseases were caused by micro organisms like bacteria. Thus pasteur proved bacteria causes diseases and koch postulates gave clear idea about how it becomes a pathogenic one.Koch's studies helps in disease prevention of bacteria.

2. The ability of an organism to defend against a disease is called immunity and such individuals having to immunity may cause infection easily. A suseptible person can affected by infection easily. The behavior of hosts has major role in their suseptibility to diseases. The characters includes;
• Age : Newborn babies and old people are more suseptable of having diseases.
• stress: The type of stress, the time of containment of stress influence the suseptibility of getting diseases.
• Heredity: The genetic identity and family background we have have greatly influence our susceptibility.
• Nutrition: The food routine, healthy diet and adequate nutrients to produce immunity factors like antibody etc also influence.
• Current medication: The side effects of medication and prolonged use of medication can reduce immunity.
• Preexisting diseases: one disease can eventually leads to another and makes you more susceptible.

3. All the three are co related and they are important in a microscope.

Magnification is the amount by which an object is enlarged when observed through a microscope. Usually it is upto the lens power.
• Resolution means the shortest distance at which a microscope can distinguish two separate things as such.
• Contrast means the clarity at which the specimen can be seen. It relates to the intensity at which light passes from background to the specimen.
All three characters are important for a microscope and the specific character important is a relative concern. The purpose we are concentrating makes the move. If we want to see a bacteria moving or a microscopic object, then magnification is enough.
But if we have to clearly see the internal structure of a cell like plant cell, we need detailing and thus contrast of a microscope has more priority. If we are looking at a cluster or colony of cells, we need to individually differentiate a cell, then resolution has more role.