Question

identify the purine from the list below:
cytosine
thymine
uracil
guanine
question 2 (1 point) ✓ saved
prophylaxis is the use of antimicrobial drugs to
treat an infection.
reduce infective dose.
prevent infection.
test susceptibility.
question 3 (1 point) ✓ saved
microbial infection damages hosts by
toxins, exoenzymes, induction of immune response.
attachment, invasion, endotoxin production.
erythrocytes, phagocytes, disintegration.
toxigenicity, autoimmunity, overactivity of immune system.
question 4 (1 point) ✓ saved
genetic engineering is also called bioengineering or biotechnology.
true
false

Explanation:

• Question 1: Purines are nitrogen - containing bases in nucleic acids. Adenine and guanine are purines. Cytosine, thymine, and uracil are pyrimidines.
• Question 2: Prophylaxis means preventing a disease or condition. In the context of antimicrobial drugs, it is used to prevent infection, not to treat an existing infection (that's therapy), reduce infective dose (not the main definition of prophylaxis in this context), or test susceptibility (that's done through susceptibility testing methods).
• Question 3: Microbial infections damage hosts through toxins (harmful substances produced by microbes), exoenzymes (enzymes secreted by microbes that can break down host tissues), and induction of an immune response (in some cases, an over - reactive or misdirected immune response to the microbe can cause host damage). Attachment and invasion are steps in the infection process, but endotoxin production is just one aspect. Erythrocytes and phagocytes are host cells, and disintegration is a result, not the main way of damage. Toxigenicity is related to toxins, but autoimmunity and over - activity of the immune system are more specific subsets that don't cover the full range like the first option.
• Question 4: Genetic engineering is a subset of biotechnology. Bioengineering is a broader field that may include aspects of engineering related to biological systems but is not exactly the same as genetic engineering. So, genetic engineering is not the same as bioengineering, and while it is a part of biotechnology, the statement that it is “also called bioengineering or biotechnology” in an equal - sense is incorrect.

Answer:

• Question 1: guanine
• Question 2: prevent infection
• Question 3: toxins, exoenzymes, induction of immune response
• Question 4: False