Practice Questions

TLS Online TPP Program

#Question id: 4601

DDT was once considered a "silver bullet" that would permanently eradicate insect pests. Instead, DDT is largely useless against many insects. Which of these would have prevented this evolution of DDT resistance in insect pests?

#Zoology

All habitats should have received applications of DDT at about the same time.
The frequency of DDT application should have been higher.
None of the insect pests would have genetic variations that resulted in DDT resistance.
DDT application should have been continual.

More Questions

#Question id: 40186

#Applied Microbiology

Which of the following are TRUE regarding the difference between Gram-positive and Gram-negative cell walls?

(A) Gram-positive walls have a thick peptidoglycan layer.

(B) Gram-negative walls contain Porin proteins.

(D) Gram-negative walls lack Teichoic acids.

Choose the correct combination:

#Question id: 40187

#Applied Microbiology

During which phase of the microbial growth cycle are cells most metabolically active and dividing at a constant maximum rate?

#Question id: 40188

#Applied Microbiology

Match the growth phase in Column A with its correct characteristic in Column B.

Column A (Phase)	Column B (Characteristic)
1. Lag Phase	A. Exponential decrease in the number of living cells.
2. Log Phase	B. Adaptation to new environment; synthesis of enzymes.
3. Stationary Phase	C. Nutrient depletion leads to equal rates of growth and death.
4. Death Phase	D. Uniform and rapid cell division; population doubles.

#Question id: 40189

#Applied Microbiology

Read the following statements regarding the bacterial growth curve and choose the correct option.

Statement I: In the Lag phase, there is an immediate increase in the cell number as bacteria start dividing instantly.

Statement II: Secondary metabolites (like antibiotics) are predominantly produced during the Stationary phase.

#Question id: 40190

#Applied Microbiology

Assertion (A): The generation time is shortest during the exponential (log) phase.

Reason (R): In the exponential phase, bacteria are adapting to the environment and repairing cellular damage.

#Question id: 40191

#Applied Microbiology

Which of the following terms describes organisms that require high hydrostatic pressure for growth and reproduction?