Topic iii-6-States)-limitations of culture based approaches quiz

Which phenomenon highlights the discrepancy between culturable and total microbial counts?

• Microbial dormancy

• Great plate count anomaly

• Viable but non-culturable state

• Poisson distribution

Answer explanation

The great plate count anomaly refers to the observation that the number of microorganisms detected by culture methods is often much lower than the total microbial counts obtained by molecular techniques, highlighting microbial diversity.

What is a major limitation of culture-dependent methods for studying environmental microbes?

• High cost of equipment

• Inability to culture all microorganisms

• Lack of trained personnel

• Excessive time required for results

Answer explanation

A major limitation of culture-dependent methods is the inability to culture all microorganisms. Many microbes are unculturable in laboratory settings, which restricts our understanding of microbial diversity and ecology.

Which of the following is NOT a reason for the unculturability of certain microorganisms?

• Dormancy

• Specific nutrient requirements

• Inability to replicate DNA

• Dependence on other microorganisms

Answer explanation

The inability to replicate DNA is not a reason for unculturability. Microorganisms can be unculturable due to dormancy, specific nutrient requirements, or dependence on other microorganisms, but DNA replication is essential for life.

What distribution do microorganisms typically follow in an environment?

• Normal distribution

• Binomial distribution

• Poisson distribution

• Uniform distribution

Answer explanation

Microorganisms often follow a Poisson distribution because they are typically counted in fixed intervals of time or space, where events occur independently and at a constant average rate.

Which technique can potentially overcome some limitations of traditional culture methods?

• Gram staining

• Colony morphology analysis

• Amoebal coculture

• Antibiotic susceptibility testing

Answer explanation

Amoebal coculture can enhance the growth of fastidious microorganisms that are difficult to culture using traditional methods, thus overcoming some limitations associated with those methods.

The ________ state refers to microorganisms that are alive but cannot be cultured using standard laboratory techniques.

Answer explanation

The correct term is 'viable but non-culturable' (VBNC) state, which describes microorganisms that are alive but cannot be grown using standard laboratory methods, making them difficult to study.

Culture-based methods often have lower ________ and ________ compared to molecular methods.

• sensitivity

• specificity

Answer explanation

Culture-based methods often have lower sensitivity compared to molecular methods, meaning they may miss detecting some pathogens. Sensitivity refers to the ability to correctly identify true positives, which is crucial in diagnostics.

The inability to mimic (a)   conditions is a significant limitation of traditional culture techniques.

Answer explanation

The correct choice is 'in vivo' because traditional culture techniques often fail to replicate the complex conditions found in living organisms, limiting their effectiveness in studying biological processes.

(a)   bacteria are particularly challenging to culture due to their specific atmospheric requirements.

Answer explanation

Anaerobic bacteria require environments devoid of oxygen, making them difficult to culture in standard laboratory conditions. Their specific atmospheric needs are why they are particularly challenging to grow.

The (a)   hypothesis suggests that some dormant microorganisms can randomly reactivate without specific environmental cues.

Answer explanation

The Scout hypothesis posits that dormant microorganisms can spontaneously reactivate without needing specific environmental triggers, highlighting their potential resilience and adaptability.