Biology

Antibiotics and Immunity

974 Questions

Prepare for your science sections with these questions on antibiotics and immunity. The hub covers various classes of antibiotics, their sources, and mechanisms of microbial resistance. It also addresses the human antiviral response.

Antibiotic classes and sourcesMicrobial resistance mechanismsAntiviral proteinsDisease treatments

Antibiotics and Immunity Questions

Multiple choice

Which of the following matches on antibiotics and their sources are true?

  1. Actinomycin: Streptomyces antibioticus
  2. Chloromycin: Streptomyces kanamyceticus
  3. Leucomycin: Streptomyces venezuelae
  4. Tetramycin: Streptomyces rimosus

  1. Only 1 and 2

  2. Only 1 and 4

  3. Only 2 and 3

  4. Only 2 and 4

  5. Only 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, both are true. Actinomycin is obtained from Streptomyces antibioticus. Tetramycin is obtained from Streptomyces rimosus.

Multiple choice

Which of the following are examples of catalase-positive bacteria?

  1. Enterobacter
  2. Enterococcus
  3. Staphylococcus
  4. Streptococcus

  1. Only 1 and 2

  2. Only 1 and 3

  3. Only 2 and 3

  4. Only 2 and 4

  5. Only 3 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Yes, it is correct. Catalase Test: The catalase test is done by placing a drop of hydrogen peroxide on a microscope slide. If the bacteria possess catalase, when a small amount of bacterial isolate is added to hydrogen peroxide, bubbles of oxygen are observed. If the mixture produces bubbles or froth, the organism is said to be 'catalase-positive' otherwise it is 'catalase-negative’. Enterobacter and Staphylococcus are examples of catalase-positive bacteria.

Multiple choice

Match the three columns List - A (antibiotics), List - B (classes) and List - C (mechanism of action).

   
List - A
List - B
List - C
P. Linezolid 1. carbacephem i. inhibiting translocation of peptidyl-tRNA
Q. Amikacin 2. aminoglycosides ii. inhibiting protein synthesis
R. Cephalexin 3. oxazolidonone iii. inhibiting peptidoglycan layer synthesis
S. Loracarbef 4. first generation cephalosporin iv. inhibiting cell wall synthesis

  1. P - 3 - ii, Q - 2 - i, R - 4 - iii, S - 1 - iv

  2. P - 2 - i, Q - 3 - iv, R - 1 - iii, S - 4 - ii

  3. P - 2 - iii, Q - 3 - ii, R - 1 - i, S - 4 - iv

  4. P - 2 - i, Q - 3 - iv, R - 1 - ii, S - 4 - iii

  5. P - 2 - i, Q - 3 - iv, R - 4 - iii, S - 1 - ii
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Linezolid belongs to oxazolidonone class and this is a Protein synthesis inhibitor that prevents the initiation step. Amikacin belongs to the aminoglycosides. Binding to the bacterial 30S ribosomal subunit inhibits the translocation of the peptidyl-tRNA from the A-site to the P-site. Cephalexin is first generation cephalosporin and It disrupts the synthesis of the peptidoglycan layer of bacterial cell walls. Loracarbef is carbacephem antibiotic. It prevents bacterial cell division by inhibiting cell wall synthesis. Hence, the correct answer using the codes is P - 3 - ii, Q - 2 - i, R - 4 - iii, S - 1 - iv.

Multiple choice

Chloromycetin is an

  1. antiseptic

  2. antidepressant

  3. analgesic

  4. antibacterial
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Chloromycetin (chloramphenicol) is a well-known antibiotic used to treat various bacterial infections.

Multiple choice

Compared to gram-negative bacteria, gram-positive bacteria

  1. retain the violet dye rather than the red

  2. are more resistant to antibiotics

  3. have less peptidoglycan

  4. have more complex cell walls
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

 Gram positive bacteria stain violet due to the presence of a thick layer of peptidoglycan in their cell walls, which retains the crystal violet these cells are stained with. Alternatively, Gram negative bacteria stain red, which is attributed to a thinner peptidoglycan wall, which does not retain the crystal violet during the decoloring process.

Multiple choice

Many bacteria are now resistant to penicillin, because

  1. penicillin causes gene mutations, some of which are beneficial

  2. previously resistant forms survived and reproduced better than susceptible forms

  3. the hospital environment inhibits competition among bacteria

  4. penicillin triggers the synthesis of resistant proteins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Many bacteria are now resistant to penicillin, because previously resistant forms survived and reproduced better than susceptible forms.

Multiple choice

Humulin is a/an

  1. antibiotic

  2. insulin

  3. haemoglobin

  4. pepsin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Humulin N (insulin isophane) is a man-made form of a hormone that is produced in the body. It works by lowering levels of glucose (sugar) in the blood. Insulin isophane is a long-acting form of insulin that is slightly different from other forms of insulin that are not man-made.Humulin N is used to treat diabetes.