BIO 251 FINAL EXAM 1) Mechnsms by which aniioies kaill or inhibit microbial grew
ID: 102546 • Letter: B
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BIO 251 FINAL EXAM 1) Mechnsms by which aniioies kaill or inhibit microbial grewh ace a) Inhibition of cell wall symmhesis b) nury to cell membrane e) Inhibition ef prolein synthesis dhibision of DNA er RNA symlbeis c) All of the abeve 2) The semisyeshetic methicillin has the advamage of a) Being broad spectru bBeing inactivated by penkihinase only on prolonged ssage c) Not being affectied by penicitinase d) All of the above c) Nene of the above 3) Which of the fellowing inmerfere with cell wal synthesis? icol a) b) Tetracyclines c) Penicillin d) Bacitracin e) Only C and D above 4) A rare but serious complication of chloramphenicol treatment ir: ) kidrey damage b) Deafness doe to damage to eighth cranial nerve c) Anemia due to suppression of bone marrow ceils d) Anemia due to destruction of circulating red blood cells e) None of the abeve microorganism may be due 10: The development of dreg resistance a) Ability of the organi sm to destroy the antibiotde b) Mutation that allows the organism to by-pass the sensitive step c) Sporulation d) All of the above 5) e) Only A and B above 6) .The synthesis of vitamins B and K by enteric bacteria provides an example: b) Symbioais c) Opportunism ) Infection c) Synergestic effeeExplanation / Answer
1) E. All of the above.
Different antibiotics have different modes of action, owing to the nature of their structure and degree of affinity to certain target sites within bacterial cells.Such as Inhibitors of cell wall synthesis,Inhibitors of cell membrane function,Inhibitors of protein synthesis and Inhibitors of DNA and RNA synthesis.
2) C.Not being affected by penicillinase.
Methicillin is a semisynthetic derivative of penicillin, which is resistant to a bacterial enzyme known as penicillinase .
3) E. Only C and D above
Penicillin and bacitracin interfere with cell wall synthesis.Penicillin acts a synergistic effect with aminoglycosides, since the inhibition of peptidoglycan synthesis permits aminoglycosides to penetrate the bacterial cell wall more permitting their disruption of bacterial protein synthesis within the cell.Bacitracin is a mixture of related cyclic peptides produced by organisms.These peptides disrupt gram positive bacteria by interfering with cell wall and peptidoglycan synthesis.
4) C. Anemia due to suppression of bone marrow cells
A rare but serious complication of chloramphenicol treatment is anemia due to suppression of bone marrow cells .Aplastic anemia is a rare disease in which the bone marrow and the hematopoietic stem cells which reside there are damaged. This causes a deficiency of all blood cell types.
5) E. Only A and B above.
The development of drug resistance in a microorganism may be due to ability of the organism to destroy the antibiotic and mutation that allows the organism to by-pass the sensitive step.
6) B. Symbiosis.
The synthesis of vitamins B and K by enteric bacteria provides an example of symbiosis. Symbiosis is the close association between two or more organisms of different species, often but not necessarily benefiting each member.
7) D. Nose, throat, and skin.
The normal habitat of Staphylococcus aureus may be nose, throat, and skin.
8) B. Intestines.
Clostridium perfringens may be found as part of the normal flora in intestines.
9) A. Endemic.
A disease constantly present in a locality is said to be endemic.
10) A.Antigens.
Foreign substances that induce a specific immune response after gaining entrance to the body are termed as antigens
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