During initial transcription, the active center of RNA polymerase is translocated forward relative to the DNA template and synthesizes short transcripts before aborting, then repeats this cycle until it escapes the promoter. Three models have been proposed to account for this;

i. Polymerase moves along the DNA.

ii. The front part of the enzyme moves along the DNA, but because of a flexible region within the enzyme, the back part of the enzyme can remain stationary at the promoter.

iii. The enzyme remains stationary and pulls the DNA into itself.

#Question id: 10907

#Unit 6. System Physiology – Plant

The mechanism of phloem translocation in angiosperms is best explained by the pressure-flow model, this model is an example of,

#Question id: 10908

#Unit 6. System Physiology – Plant

The energy is necessary to move photosynthate from producing cells into the sieve elements. This movement of photosynthate is called

#Question id: 10909

#Unit 6. System Physiology – Plant

The energy is essential for some aspects of movement from sieve elements to sink cells, which store or metabolize the sugar. This movement of photosynthate from sieve elements to sink cells is called

#Question id: 10910

#Unit 6. System Physiology – Plant

In early research on phloem translocation, both active and passive mechanisms were considered. All theories, both active and passive, assume an energy requirement in both sources and sinks. What will be the INCORRECT explanation of active and passive mechanism?

#Question id: 10911

#Unit 6. System Physiology – Plant

Researchers have investigated bidirectional transport by applying two different radiotracers to two source leaves, one above the other. Researcher wanted to see how bidirectional transport happens in sieve elements. Which one of the following is INCORRECT interpretation for bidirectional transport?

#Question id: 10912

#Unit 6. System Physiology – Plant

Velocities for transport in the phloem are measured by using a technique which detect water flow;