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 antibiotic penicillin is obtained from

  1. Penicillium camemberti

  2. Penicillium bilaiae

  3. Penicillium chrysogenum

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

Penicillium chrysogenum is common in damp or water damaged buildings. It is the source of several β-lactam antibiotics. The most important antibiotic penicillin is obtained from it.

Multiple choice

Which of the following statements is false regarding antibiotics?

  1. The term was given by Waksman.

  2. They are produced by microorganisms.

  3. They either kill bacteria or keep them for reproducing.

  4. They do not fight infections caused by virus such as cold and flu.

  5. They may cause at least some relief in case of viral infection.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Each time the antibiotics are taken, it increases the chances that bacteria in the body will be able to resist them. Later, we could get or spread an infection that those antibiotics cannot cure.

Multiple choice

A researcher observed zone of inhibition of a fungus among bacterial colonies. He presumed it to be due to antibiotic production, which is a _______.

  1. primary metabolite

  2. secondary metabolite

  3. tertiary metabolite

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

Secondary metabolite: Primary metabolites produced by microorganisms are enzymes, vitamins, etc., that are required for their own living. Secondary metabolites are antibiotics that help them to survive in their surroundings, by inhibiting other organisms.

Multiple choice

During antibiotic as erythromycin production by Streptomyces erythreus the following data was collected. 1 hour (100 cells, 0 erythromycin); 5 hours (1500 cells, 15 units erythromycin); 10 hours (25,000 cells, 35 units erythromycin); 15 hours (65,000 cells, 45 units erythromycin); 20 hours (64,000 cells, 60 units erythromycin); 25 hours (50,000 cells, 50 units erythromycin).

How many cells were present in the log phase of Streptomyces erythreus?

  1. 65,000

  2. 64,000

  3. 50,000

  4. 25,000
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

25,000: log phase means when the cells are rapidly growing and at their maximum rate of division. Here log phase is in 10th hour and correspondingly, number of cells = 25,000.

Multiple choice

During antibiotic as erythromycin production by Streptomyces erythreus the following data was collected. 1 hour (100 cells, 0 erythromycin); 5 hours (1500 cells, 15 units erythromycin); 10 hours (25,000 cells, 35 units erythromycin); 15 hours (65,000 cells, 45 units erythromycin); 20 hours (64,000 cells, 60 units erythromycin); 25 hours (50,000 cells, 50 units erythromycin).

Which is the most suitable time for harvesting erythromycin?

  1. 10 hours

  2. 15 hours

  3. 20 hours

  4. 25 hours
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

25 hours: even though, maximum yield of erythromycin is at 20th hour (60 units) but all product are harvested at the end of fermentation, i.e. 25 hours here.

Multiple choice

What is the meaning of antiseptic?

  1. Something which is healthy to eat

  2. Something that kills germs

  3. Something which one should drink

  4. Something that makes you beautiful

  5. Something to wash hairs
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Antiseptic are the lotions and creams that kills germs. One should keep immediately on the wound or injury to kill germs.

Multiple choice

Antibiotic penicillin acts against bacteria by which of the following ways?

  1. Killing the bacteria.

  2. Blocking nutritional pathways for the bacteria.

  3. Neutralizing the bacteria.

  4. Blocking biochemical pathways important for bacteria.

  5. Reducing the effect of the bacteria.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Antibiotic penicillin blocks biochemical pathways important for bacteria. This inhibits the growth of bacteria or kills it.

Multiple choice

Which of the following statements regarding bacitracin is correct?

  1. Bacitracin is used for the treatment of MRSA (methicillin resistant Staphylococcus aureus).

  2. Ribosomes are involved in the synthesis of bacitracin.

  3. Bacitracin can be used to distinguish Streptococcus pyogenes from other 'strep' bacteria.

  4. Bacitracin alters bacterial outer-membrane permeability.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct statement. Bacitracin can be used to distinguish Streptococcus pyogenes from other 'strep' bacteria because Streptococcus pyogenes is sensitive to bacitracin while others are resistant.

Multiple choice

Which of the following statements about teixobactin is true?

  1. It is widely used against Gram-positive bacteria.

  2. Mycobacteria soon develops resistance to this antibiotic.

  3. It inhibits cell wall synthesis by binding to lipid II molecule.

  4. It inhibits isoprenyl pyrophosphate, a molecule that carries the building blocks of the peptidoglycan bacterial cell wall.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is the correct answer. Teixobactin is an inhibitor of cell wall synthesis that acts primarily by binding to lipid II, a fatty molecule which is a precursor to peptidoglycan. Binding of teixobactin to lipid precursors inhibits production of the peptidoglycan layer, leading to lysis of vulnerable bacteria.