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

Dettol and savlon are

  1. anticeptics

  2. antibiotics

  3. disinfectants

  4. antimicrobials
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This option is correct as dettol and savlon are disinfectants.

Multiple choice

Bacillus anthracis and Escherichia coli are the two most prominent extracellular bacterial pathogens. Extracellular bacteria try to avoid killing by

  1. activating neutrophils

  2. accelerating complement activation

  3. synthesising capsules

  4. deviating complement deposition to the cell membrane

  5. limiting variation in their antigens
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Capsules do not adhere readily to phagocytic cells and may cover carbohydrate molecules which could be recognised by phagocyte receptors.

Multiple choice

One of the most common and potentially serious bacteria to cause severe ear infections is the pneumococcus. In a lymph node, the antigen pneumococcus polysaccharide SIII leads to _______________________.

  1. lymphocyte proliferation in the paracortex

  2. PALS development

  3. development of cellular hypersensitivity

  4. proliferation in cortical lymphoid follicles

  5. the absence of germinal centers
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Stimulation of antibody-formation by this thymus-independent antigen leads to proliferation in this location with development of germinal centers while the paracortical region remains inactive, reflecting the inability to develop cellular hypersensitivity to the polysaccharide.

Multiple choice

An antiseptic is a substance that checks the growth & action of microorganisms especially in or on living tissue.The dye acting as a topical antiseptic is

  1. new fuchsine

  2. pararosaniline

  3. crystal violet

  4. congo red
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Crystal violet i a triarylmethane dye. The dye is used as a histological stain and in Gram's method of classifying bacteria. Crystal violet has antibacterial, antifungal, and anthelmintic properties and is used as a topical antiseptic.

Multiple choice

The antibiotic 'cycloserine' is obtained from

  1. Streptomyces orchidaceus

  2. Streptomyces fradiae

  3. Streptomyces orientalis

  4. Actinoplanes teichomyceticus

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

Cycloserine antibiotic is obtained from Streptomyces orchidaceus.

Multiple choice

Nocadazole is used

  1. to obtain pure culture

  2. to obtain synchronous culture

  3. as a differentiating agent in media

  4. to enhance the bacterial growth
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Nocadazole is frequently used in cell biology laboratories to synchronise the cell division cycle. Nocadazole-treated cells enter mitosis but cannot form metaphase spindles because microtubules cannot polymerise. Thus, cell gets arrested in prometaphase.

Multiple choice

The antibiotic penicillin is obtained from

  1. Bacteria

  2. Plants

  3. Sea weeds

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

Penicillin was discovered by Alexander Fleming in 1928 and is derived from the Penicillium fungus, specifically Penicillium notatum. It revolutionized medicine as the first true antibiotic and is not obtained from bacteria, plants, or seaweed.

Multiple choice

Which of the following antibiotics are derived from the members of genus of the family Streptomycetaceae?

  1. Oxytetracycline, Bacitracin, Streptomycin

  2. Chloramphenicol, Penicillin, Griseofulvin

  3. Chloramphenicol, Oxytetracycline, Streptomycin

  4. Chloramphenicol, Griseofulvin, Oxytetracycline

  5. Streptomycin, Griseofulvin, Penicillin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Streptomycin: Streptomyces griseus Chloramphenicol: Streptomyces venezuelae Oxytetracycline: Streptomyces rimosus All are derived from members of genus of the family Streptomycetaceae.

Multiple choice

Which one of the following is antimetabolites of bacteria?

  1. PABA

  2. Para-Aminobenzenesulphonamide

  3. Both (1) & (2)

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

Para-aminobenzenesulphonamide (sulphanilamide) is a sulfa drug that acts as an antimetabolite. It competes with para-aminobenzoic acid (PABA), which bacteria need to synthesize folic acid. By mimicking PABA structure, it disrupts bacterial folate synthesis, killing the bacteria. PABA itself is not an antimetabolite - it's the metabolite bacteria actually need.

Multiple choice

Which of the following is not a broad spectrum antibiotic?

  1. Ampicillin

  2. Tetracyclic

  3. Chloroamphenicol

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

Ampicillin is a narrow-spectrum penicillin antibiotic effective mainly against Gram-positive bacteria. Broad-spectrum antibiotics like Tetracycline, Chloramphenicol, and Fluoroquinolones work against both Gram-positive and Gram-negative bacteria. The question identifies the one that is NOT broad-spectrum.

Multiple choice

Which one of the following is an antibiotic?

  1. Aspirin

  2. Brufen

  3. Chloromycetin

  4. Chloroquine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Chloromycetin (chloramphenicol) is an antibiotic that inhibits bacterial protein synthesis. Aspirin and Brufen are analgesics/anti-inflammatory drugs, not antibiotics. Chloroquine is an antimalarial drug. Only Chloromycetin among the options is actually an antibiotic.

Multiple choice

Which of the following statements is not true?

  1. Some disinfectants can be used as antiseptics at low concentration.

  2. Sulphadiazine is a synthetic antibacterial.

  3. Ampicillin is natural antiboitic.

  4. Aspirin is both analgesic and antipyretic.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ampicillin is a semi-synthetic penicillin derivative, not a natural antibiotic. Natural penicillins (like penicillin G and V) are produced directly by Penicillium mold, while ampicillin is chemically modified.