Question

Please answer 1-7

1. Based on LD₅₀ values, which of these is the most toxic/lethal?

   		Botulinum toxin: LD50=0.03 ng/kg
   		Shiga toxin: LD50=250 ng/kg
   		Staphylococcal enterotoxin: LD50=1350 ng/kg
   		Abrin toxin: LD50= 20,000 ng/kg

1. Which of the following is not a communicable disease?

   		malaria
   		HIV / AIDS
   		tetanus
   		tuberculosis

1. Which of these best defines pathogenesis?

   		the abnormal state in which the body is not functioning normally
   		the origin and development of a specific disease
   		the study of strictly bacterial diseases
   		the study strictly viral diseases

1. The LAL (Limulus amebocyte lysate) assay is used to detect the presence of ____________.

   		exotoxins
   		endotoxins
   		fungal pathogens
   		helminthes

1. Live microbes that are applied to or ingested into the human body to exert a beneficial effect are defined as ___________________.

   		antibiotics
   		prebiotics
   		probiotics
   		none of these

1. Where does B cell differentiation take place in adult humans?

   		bone marrow
   		thymus
   		heart
   		none of the above

1.

Which of the following definitions is incorrect?

		acute: a short-lasting primary infection
		chronic: a disease that develops slowly and lasts for a long period of time
		primary infection: an initial illness
		secondary infection: are always a long-lasting illness

Answer 1

Answer 1: The median lethal dose (or LD50) is the amount of the substance required (usually per body weight) to kill 50% of the test population. In general, the smaller the LD50 value, the more toxic the chemical is. Botulinum toxin has LD50 value 0.03 ng/kg which is less than other three shiga toxin, Staphylococcal enterotoxin and abrin toxin. So most lethal is botulinum toxin.

So correct option is (a).

Answer 2: A communicable disease is one that is spread from one person to another.HIV ,Malaria and tuberculosis spreads from one person to another person through different means. Thease are the communicable diseases.  Tetanus is a non-communicable disease. It is not spread from person to person.

So correct option is (c).

Answer 3: The pathogenesis of a disease is the biological mechanism that leads to a diseased state. Pathogenesis also describe the origin and development of the disease.According to this the option which defines the pathogenesis is option (b) the origin and development of a specific disease.

So correct opion is (b).

Answer 4: The LAL (limulus amebocyte lysate) testing, also known as bacterial endotoxin testing, is an in vitro assay used to detect the presence and concentration of bacterial endotoxins in drugs and biological products.

So correct option is (b). Endotoxin

Answer 5: Probiotics are live bacteria that can be found in yogurt and other fermented foods. Probiotic bacteria must be kept alive to be active. Prebiotics are a type of fiber that the human body cannot digest. They serve as food for probiotics.

So Live microbes that are applied to or ingested into the human body to exert a beneficial effect are defined as probiotics.

So, Correct option is (c).

Answer 6: B cell differentiation takes place in bone marrow of adult human. Option b is incorrect because in thymus t cell differentiation occurs. Option c is also incorrect because heart is not place for differentiation of B cells or T cells.

So correct option is (a).

Answer 7: The definition of acute, chronic and primary infection is correct. Definition of secondary infection is incorrect.

Secondary infection is the infection that follows and results from an earlier infection, injury, or event.

So correct option is (d).