DNA replication is studied in a newly discovered bacterium. It takes 30 min for the bacterium to complete a round of replication at 37oC. A Meselson-Stahl-type experiment was performed. The bacteria were grown for several generations in 14N-medium and then switched to 15N-medium. The DNA molecules were then analyzed.

If the mechanism of DNA replication in this bacterium were semi-conservative, what results would be found when the double-stranded DNA was analyzed in a CsCl density gradient after three generations in 15N-medium?

#Question id: 10506

#Unit 6. System Physiology – Plant

Plant growth promoting rhizobacteria (PGPRs) such as Pseudomonas aeruginosa, that alleviate plant abiotic or biotic stress in soil by releasing of

#Question id: 10507

#Unit 6. System Physiology – Plant

Rhizobacteria function as

 a) Nitrogen fixation

 b) depositing pathogens directly into the vascular system,

 c) producing antibiotics and antifungal agents for inhibiting soil pathogens

 d) herbivore sensors by sending electrical or chemical signals to surrounding cells

 Which one of the following combination is correct?

#Question id: 10508

#Unit 6. System Physiology – Plant

Glandular trichomes store species-specific secondary metabolites in a pocket formed between the cell wall and the cuticle. These secondary metabolites are-

#Question id: 10509

#Unit 6. System Physiology – Plant

A different type of mechanical obstacle to herbivory is provided by mineral crystals that are present in many plant species, such as silica crystals known as

#Question id: 10510

#Unit 6. System Physiology – Plant

Constitutive chemical defenses are effective against many different herbivores, including insects and mammals. Hemlock (Cicuta sp.) produces which toxins that a polyacetylene prolongs the repolarization of neuronal action potentials.

#Question id: 10511

#Unit 6. System Physiology – Plant

Which type of pumps inhibits digitoxin in the membranes of heart cells, leading to increased myocardial contraction?