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 is a pair of catalase-positive bacteria?

  1. Enterobacter and Klebsiella

  2. Enterococcus and Streptococcus

  3. Enterobacter and Enterococcus

  4. Enterococcus and Klebsiella

  5. Klebsiella and 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 and Klebsiella: Catalase-positive bacteria.

Multiple choice

Directions: Choose the option which can substitute the following sentence.

A medicine that can destroy harmful bacteria in the body.

  1. Antibiotic

  2. Destructs organism

  3. Killer of germs

  4. Killer of bacteria
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Antibiotic is the specific medical term for medicines that kill or inhibit the growth of bacteria. The other options are descriptive phrases rather than the proper scientific terminology. Antibiotics work by targeting bacterial cell structures or metabolic processes.

Multiple choice

Which of the following is a set of aminoglycoside antibiotics?

  1. Amikacin, Carbomycin and Kanamycin

  2. Amikacin, Gentamicin and Kanamycin

  3. Carbomycin, Erythromycin and Metacycline

  4. Carbomycin, Erythromycin and Gentamicin

  5. Erythromycin, Gentamicin and Metacycline
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct answer. Amikacin, Gentamicin, Kanamycin all are aminoglycoside antibiotics.

Multiple choice

ASSERTION (A): Gram-positive bacteria are generally resistant to complement-mediated lysis. REASON (R): In Gram-positive bacteria, thick peptidoglycan layer prevents insertion of membrane attack complex into the inner membrane.

Directions: In the following question there are two statements, Assertion (A) and Reason (R). Consider both the statements independently and mark your answer as under:

1. If A and R both are correct and R is the correct explanation of A
2. If A and R both are correct and R is not the correct explanation of A
3. If A is correct and R is incorrect 
4. If A is incorrect and R is correct
5. If A and R both are incorrect

  1. 1

  2. 2

  3. 3

  4. 4

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

Assertion as well as reason statements are correct and R is the correct explanation of A. Gram-positive bacteria are generally resistant to complement-mediated lysis because thick peptidoglycan layer prevents insertion of membrane attack complex into the inner membrane.

Multiple choice

Which of the following statements is false?

  1. Gram staining was developed by Dutch Physician Hans Christian Gram in 1883.

  2. Gram positive bacteria has a thick peptidoglycan layer.

  3. Gram negative bacteria has a very low lipid content in cell wall.

  4. In Gram staining, alcohol acts on membrane lipids.

  5. Acid fast stain was developed by Franz Ziehl and the pathologist Friedric Neelsen.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This is a false statement. Gram staining was developed by Danish Physician Hans Christian Gram in 1883, he was not a Dutch physician.

Multiple choice

The outer membrane of gram-negative bacteria contains

  1. cytoplasm

  2. teichoic acids

  3. a thick peptidoglycan layer

  4. lipoteichoic acids

  5. lipopolysaccharide
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Outer membrane of gram-negative bacteria contains lipopolysaccharide in its outer leaflet and phospholipids in the inner leaflet.

Multiple choice

Gram staining is a method of

  1. negative staining

  2. acid fast staining

  3. differential staining

  4. endospore staining

  5. simple staining
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Gram staining is a type of Differential method, used to distinguish gram positive and gram negative bacteria.

Multiple choice

Chelating agents, for certain types of adherence, are found in

  1. Peptidoglycan, found in both Gram positive and negative organisms.

  2. Lipopolysaccharide are found in Gram positive organisms.

  3. Lipopolysaccharide are found in Gram negative organisms.

  4. Teichoic and lipoteichoic acids are found in Gram positive organisms.

  5. Teichoic and lipoteichoic acids are found in Gram negative organisms.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Teichoic acids and lipoids are present, forming lipoteichoic acids , which serve as chelating agents, and also for certain types of adherence, which assist in anchoring the peptidoglycan

Multiple choice

Which of the following statements is true for Gram negative organisms?

  1. Due to presence of higher lipid content, after alcohol-treatment, the porosity of the cell wall increases, hence the CVI complex (Crystal violet -Iodine) can pass through. Thus, the primary stain is not retained.

  2. Due to presence of rich level of peptidoglycan, after alcohol-treatment, the porosity of the cell wall increases, hence the CVI complex (Crystal violet -Iodine) can pass through. Thus, the primary stain is not retained.

  3. Primary stain retain after counter stain, violet or purple colour in Gram negative.

  4. Gram negative organisms lacks the secondary membrane and lipopolysaccharide.

  5. Gram negative organisms have teichoic acids or lipoteichoic acids.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

True statement: Gram negative has higher lipid content, after alcohol-treatment, the porosity of the cell wall increases, hence the CVI complex (Crystal violet -Iodine) can pass through. Thus, the primary stain is not retained. It become red or pink in colour and can differentiate between Gram negative and Gram positive organisms.

Multiple choice

Penicillin, an antibiotic, is obtained from a

  1. flowering plant

  2. fungus

  3. virus

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

Penicillin was the first true antibiotic, discovered by Alexander Fleming in 1928. It is derived from the Penicillium mold, which is a type of fungus.

Multiple choice

Penicillin is given to a patient in order to

  1. prevent any rise in body temperature

  2. cure all diseases

  3. cure hereditary disease

  4. prevent the growth of several types of diseases causing bacteria
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Penicillin is an antibiotic that works by interfering with the ability of bacteria to synthesize cell walls. This inhibits their growth and helps the body's immune system eliminate the infection.

Multiple choice

Match List - A (antibiotics), List - B (classes) and List - C (mechanism of action) and select the correct answer using the codes given below in the lists.

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

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

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

  3. P - 2 - i, Q - 3 - ii, R - 1 - iii, 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
E Correct answer
Explanation

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