Question 1

Which antimicrobic does not interfere with protein synthesis?
A)aminoglycosides
B)tetracyclines
C)erythromycin
D)trimethroprim
E)chloramphenicol

Accepted Answer

Trimethroprim belongs to the class of antimicrobics known as folate antagonists, which interfere with the synthesis of nucleic acids but not protein synthesis. Aminoglycosides, tetracyclines, erythromycin, and chloramphenicol all interfere with protein synthesis by targeting different components of the ribosome.

Question 2

Substances that are naturally produced by certain microorganisms that can inhibit or destroy other microorganisms are called
A)antibiotics.
B)narrow-spectrum drugs.
C)semisynthetic drugs.
D)synthetic drugs.
E)broad-spectrum drugs.

Accepted Answer

Antibiotics are naturally produced substances by microorganisms that can inhibit or destroy other microorganisms. Narrow-spectrum drugs are drugs that target a specific group of microorganisms, semisynthetic drugs are modified from naturally occurring substances, and synthetic drugs are entirely man-made. Broad-spectrum drugs can target a wide range of microorganisms but may also harm beneficial ones.

Question 3

Antimicrobics effective against a wide variety of microbial types are termed
A)antibiotics.
B)narrow-spectrum drugs.
C)semisynthetic drugs.
D)synthetic drugs.
E)broad-spectrum drugs.

Accepted Answer

Broad-spectrum drugs are effective against a wide variety of microbial types, including both gram-positive and gram-negative bacteria, as well as some fungi and viruses. Antibiotics, narrow-spectrum drugs, semisynthetic drugs, and synthetic drugs are broader categories that may or may not be effective against a wide variety of microbial types.

Question 4

Aminoglycosides
A)interfere with elongation of peptidoglycan.
B)are metabolic analogs of PABA and block folic acid synthesis.
C)attach to the 30S ribosomal subunit and disrupt protein synthesis.
D)damage cell membranes.
E)block peptidases that cross-link glycan molecules.

Accepted Answer

Aminoglycosides attach to the 30S ribosomal subunit and disrupt protein synthesis, eventually leading to cell death. They do not interfere with elongation of peptidoglycan, block folic acid synthesis, damage cell membranes, or block peptidases that cross-link glycan molecules.

Question 5

Broad-spectrum drugs that disrupt the body's normal flora often cause
A)nephrotoxicity.
B)superinfections.
C)allergic reactions.
D)drug toxicity.
E)All of these choices are correct.

Accepted Answer

Broad-spectrum drugs that disrupt the body's normal flora often cause superinfections because they not only kill harmful bacteria but also beneficial ones that keep the body in balance, hence creating an opportunity for other microorganisms like fungi to overgrow, resulting in a superinfection. The other options, including nephrotoxicity, allergic reactions, and drug toxicity, are possible side effects but do not happen as frequently as superinfections.

Question 6

Gram-negative bacilli are often treated with
A)penicillin G.
B)vancomycin.
C)aminoglycosides.
D)synercid.
E)isoniazid.

Accepted Answer

Gram-negative bacilli are often treated with aminoglycosides, such as gentamicin or amikacin, as they are effective against these bacteria. Penicillin G is effective against gram-positive bacteria, and vancomycin is typically reserved for treating gram-positive infections that are resistant to other antibiotics. Synercid is an antibiotic used to treat gram-positive bacteria, and isoniazid is used primarily for the treatment of tuberculosis.

Question 7

Which antimicrobic does not inhibit cell wall synthesis?
A)gentamicin
B)vancomycin
C)cephalosporins
D)penicllins
E)clavamox

Accepted Answer

Gentamicin is an aminoglycoside antibiotic that inhibits protein synthesis in bacteria, but it does not inhibit cell wall synthesis. The other options, vancomycin, cephalosporins, penicillins, and clavamox, all inhibit cell wall synthesis.

Question 8

A chemical that inhibits beta-lactamase enzymes is
A)synercid.
B)penicillinase.
C)aztreonam.
D)clavulanic acid.
E)imipenem.

Accepted Answer

Clavulanic acid is a beta-lactamase inhibitor that is commonly used in combination with penicillins to enhance their effectiveness against resistant bacteria. Synercid, aztreonam, and imipenem are antibiotics but are not beta-lactamase inhibitors, while penicillinase is a type of beta-lactamase enzyme that is inhibited by clavulanic acid.

Question 9

Antimicrobics that are macrolides
A)disrupt cell membrane function.
B)include tetracyclines.
C)include azithromycin, clarithromcyin, and erythromycin.
D)are very narrow-spectrum drugs.
E)are hepatotoxic.

Accepted Answer

Macrolides include azithromycin, clarithromycin, and erythromycin. They inhibit bacterial protein synthesis by binding to the 50S ribosome. They are used to treat respiratory and soft tissue infections caused by bacteria such as streptococci, staphylococci, and mycoplasmas.

Question 10

All of the following pertain to cephalosporins except
A)they have a beta-lactam ring.
B)greater resistance to beta-lactamases.
C)newer generations have activity against gram negatives.
D)many administered by injection not orally.
E)they are synthetic drugs.

Accepted Answer

Cephalosporins are not synthetic drugs but they are derived from a mold called Cephalosporium acremonium.

Question 11

Antibiotics are derived from all the following except
A)Penicillium.
B)Bacillus.
C)Staphylococcus.
D)Streptomyces.
E)Cephalosporium.

Accepted Answer

Staphylococcus is a genus of bacteria, not a source of antibiotics. Antibiotics are typically derived from fungi like Penicillium and Cephalosporium, or bacteria like Bacillus and Streptomyces.

Question 12

Ampicillin, amoxicillin, mezlocillin, and penicillin G all have
A)a beta-lactam ring.
B)resistance to the action of penicillinase.
C)a semisynthetic nature.
D)an expanded spectrum of activity.
E)All of the choices are correct.

Accepted Answer

All the given antibiotics including Ampicillin, amoxicillin, mezlocillin, and penicillin G have a beta-lactam ring in their chemical structure, which is the unique feature of penicillin antibiotics.

Question 13

Salvarsan was
A)discovered in the mid 1900s.
B)used to treat syphilis.
C)formulated from the red dye prontosil.
D)first discovered as a product of Penicillium notatum.
E)discovered by Robert Koch.

Accepted Answer

Salvarsan was discovered by Paul Ehrlich in 1908 and was the first effective treatment for syphilis.

Question 14

Important characteristics of antimicrobic drugs include
A)readily delivered to the site of infection.
B)high toxicity against microbial cells.
C)do not cause serious side effects in humans.
D)remains active in body tissues and fluids.
E)All of these choices are correct.

Accepted Answer

All of the listed characteristics are important for antimicrobic drugs. They must be able to reach the site of infection, have high toxicity against microbial cells but not cause serious side effects in humans, and remain active in body tissues and fluids to be effective.

Question 15

All of the following pertain to fluoroquinolones except
A)they are broad spectrum.
B)they include ciprofloxacin and levofloxacin.
C)they are nephrotoxic.
D)they are used to treat respiratory, urinary, and sexually-transmitted infections.
E)they work by inhibiting bacterial DNA replication.

Accepted Answer

Fluoroquinolones are broad-spectrum antibiotics, including ciprofloxacin and levofloxacin, used to treat respiratory, urinary, and sexually transmitted infections. They work by inhibiting bacterial DNA replication. However, they are not nephrotoxic, meaning they do not have toxic effects on the kidneys.

Question 16

Sulfonamides
A)interfere with elongation of peptidoglycan.
B)are metabolic analogs of PABA and block folic acid synthesis.
C)attach to the 30S ribosomal subunit and disrupt protein synthesis.
D)damage cell membranes.
E)block peptidases that cross-link glycan molecules.

Accepted Answer

Sulfonamides are metabolic analogs of PABA (para-aminobenzoic acid) and they block folic acid synthesis. Folic acid is an essential nutrient for bacteria and it plays a key role in DNA synthesis. Sulfonamides block the synthesis of folic acid by inhibiting the enzyme dihydropteroate synthase, which converts PABA into dihydrofolic acid. Without folic acid, bacteria cannot synthesize DNA and they eventually die.

Question 17

Which of these drugs is useful in treating infections by methicillin-resistant S.aureus and vancomycin-resistant Enterococcus?
A)tetracycline
B)isoniazid
C)linezolid
D)aminoglycosides
E)cephalosporins

Accepted Answer

Linezolid is the only drug listed that is effective against both methicillin-resistant S. aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Tetracycline, aminoglycosides, and cephalosporins may be effective against MRSA, but not VRE. Isoniazid is primarily used for treating tuberculosis and is not effective against either MRSA or VRE.

Question 18

Which is mismatched?
A)Fleming-penicillin
B)Domagk-sulfonamide
C)Ehrlich-tetracycline
D)Florey and Chain-penicillin

Accepted Answer

Tetracycline was discovered by Benjamin Minge Duggar in 1945, more than 15 years after the death of Paul Ehrlich. Ehrlich is known for his contributions to immunology, chemotherapy, and for developing the first synthetic antimicrobial drug, Salvarsan, which was used to treat syphilis.

Question 19

Penicillins and cephalosporins
A)interfere with DNA synthesis.
B)are metabolic analogs of PABA and block folic acid synthesis.
C)attach to the 30S ribosomal subunit and disrupt protein synthesis.
D)damage cell membranes.
E)block the peptidases that cross-link glycan molecules.

Accepted Answer

Penicillins and cephalosporins are beta-lactam antibiotics that inhibit the final step of bacterial cell wall synthesis, which is the cross-linkage of peptidoglycan molecules. Beta-lactams block the activity of penicillin binding proteins (PBPs), which are enzymes responsible for this cross-linking. By inhibiting PBPs, these antibiotics prevent the formation of a strong and stable cell wall, leading to bacterial lysis and death.

Question 20

Which of these drugs is used to treat cases of tuberculosis?
A)penicillin G.
B)vancomycin.
C)aminoglycosides.
D)synercid.
E)isoniazid.

Accepted Answer

Isoniazid is a first-line medication used to treat tuberculosis (TB). It works by inhibiting the synthesis of mycolic acids, which are important components in the cell walls of the bacteria that cause TB. Penicillin G, vancomycin, aminoglycosides, and synercid are not used to treat tuberculosis.

Quiz 12: Drugs, Microbes, Host--The Elements of Chemotherapy

Which antimicrobic does not interfere with protein synthesis?

Substances that are naturally produced by certain microorganisms that can inhibit or destroy other microorganisms are called

Antimicrobics effective against a wide variety of microbial types are termed

Aminoglycosides

Broad-spectrum drugs that disrupt the body's normal flora often cause

Gram-negative bacilli are often treated with

Which antimicrobic does not inhibit cell wall synthesis?

A chemical that inhibits beta-lactamase enzymes is

Antimicrobics that are macrolides

All of the following pertain to cephalosporins except

Antibiotics are derived from all the following except

Ampicillin, amoxicillin, mezlocillin, and penicillin G all have

Salvarsan was

Important characteristics of antimicrobic drugs include

All of the following pertain to fluoroquinolones except

Sulfonamides

Which of these drugs is useful in treating infections by methicillin-resistant S.aureus and vancomycin-resistant Enterococcus?

Which is mismatched?

Penicillins and cephalosporins

Which of these drugs is used to treat cases of tuberculosis?