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TLS Online TPP Program

#Question id: 12251

A plant produces flowers that are open through the day and the night. An experimenter places pollen on the stigmas of freshly opened flowers and covers them after pollination to prevent natural pollinators from having access to the flowers. When experimental pollination was carried out during the day, 40% of the flowers yielded fruit. When experimental pollination was carried out during the night, 80% of the flowers yielded fruit. However, when flowers were  kept  open  to  natural  pollination  during  the  day  (covered  at  night),  35%  of  flowers  produced  fruit.  20%  of flowers exposed to natural pollination during the night (covered during the day) produced fruit. Which of the following statements is NOT a plausible explanation of these results ?

#Unit 10. Ecological Principles
  1. Night pollinators are low in abundance
  2. Night pollinators are abundant
  3. Night pollinators are low in pollination efficiency
  4. Pollinators are active during the day
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TLS Online TPP Program

#Question id: 13198

#Unit 6. System Physiology – Plant

The sugar is a carbohydrate that are generally translocated  in the phloem in which form?
TLS Online TPP Program

#Question id: 13199

#Unit 6. System Physiology – Plant

The non-reducing sugar sucrose is most commonly translocated in the phloem rather than reducing sugar. Why?
a.) because they are less reactive than their reducing counterparts
b.) because sucrose contains more energy than a monosaccharides
c.) because the ketone or aldehyde group is reduced to an alcohol or combined with a similar group on another sugar so as not to be oxidized 
Which one of the following statements is true about translocation of non-reducing sugar?
TLS Online TPP Program

#Question id: 13200

#Unit 6. System Physiology – Plant

In the modification of translocation pathways, Interference with a translocation pathway by wounding or pruning can alter the patterns established by proximity and vascular connections. In the absence of direct connections between source and sink, vascular interconnections, called
TLS Online TPP Program

#Question id: 11804

#Unit 6. System Physiology – Plant

P-proteins have been characterized at the molecular level. P-proteins from the genus Cucurbita consist of two major proteins;
TLS Online TPP Program

#Question id: 11801

#Unit 6. System Physiology – Plant

Which one of the following compound most commonly transported in sieve elements of the phloem?
TLS Online TPP Program

#Question id: 11800

#Unit 6. System Physiology – Plant

There are at least three different types of companion cells in the minor veins of mature, exporting leaves. Which of the following statements about these companion cells is CORRECT?

 a.) transfer cells are transport sugars enter the apoplast during the movement of sugars from mesophyll cells to sieve elements. Transfer cells transport sugars from the apoplast to the symplast of the sieve elements and companion cells in the source.

 b.) the numerous mitochondria in companion cells may supply energy as ATP to the sieve elements

 c.) Ordinary companion cells can function in either symplastic or apoplastic short-distance transport in source leaves, depending in part on plasmodesmatal frequencies

 d.) Intermediary cells, by contrast, function in symplastic transport of sugars from mesophyll cells to sieve elements