Biology

Antibiotics and Immunity

859 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

The concentration of IgD is low in serum because

  1. IgD is highly unstable

  2. IgD is membrane bound

  3. IgD is produced in minuscule amounts

  4. IgD is an intracellular antibody
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

IgD is a membrane bound immunoglobulin, because of which there is lesser concentration of IgD in serum.

Multiple choice

D-glutamic acid is found in the capsule of

  1. Shigella flexneri

  2. Bacillus anthracis

  3. Treponema pallidum

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

The capsule of Bacillus anthracis is entirely made up of D-glutamic acid. This amino acid is rare as most of the other capsules contain L form of amino acid.

Multiple choice

Name the fungi producing antibiotics.

  1. Penicillium expansum

  2. Penicillium digibatum

  3. Penicillium itallicum

  4. Penicillium notatum

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Penicillium notatum is the original fungus from which Alexander Fleming isolated penicillin in 1928, revolutionizing medicine. Other Penicillium species may produce different compounds, but notatum is famous for the first antibiotic discovery.

Multiple choice

Which of the following sets represents catalase-positive bacteria only?

  1. Enterobacter, Klebsiella, Nocardia, Staphylococcus

  2. Enterococcus, Klebsiella, Nocardia, Streptococcus

  3. Enterobacter, Enterococcus, Staphylococcus, Streptococcus

  4. Enterococcus, Klebsiella, Nocardia, Staphylococcus

  5. Klebsiella, Nocardia, Staphylococcus, Streptococcus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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, Klebsiella, Nocardia, and Staphylococcus: All are catalase-positive bacteria.

Multiple choice

Which of the following mediums are selective for Gram-negative bacteria? P. Hektoen enteric agar Q. MacConkey agar R. Mannitol salt agar S. Yeast Malt Agar

  1. P and Q

  2. P and S

  3. Q and R

  4. Q and S

  5. R and S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hektoen Enteric Agar is a selective and differential agar for the isolation and cultivation of gram-negative enteric microorganisms, especially Salmonella and Shigella. MacConkey Agar is a selective and differential medium designed to isolate and differentiate Gram-negative enterics based on their ability to ferment lactose.