One summer the moose population on Island was unusually high, and park naturalists noticed signs of malnutrition among the  adults.  The wolf population  was  fairly  low,  near  20.  That  winter,  for  the  first  time  in  many  years,  a substantial  number of seemingly healthy adult moose as well as calves and crippled animals were killed and eaten by wolves. This description is part of a general situation in which the wolf and moose populations

#Question id: 10922

#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?

#Question id: 10921

#Unit 6. System Physiology – Plant

The mechanism of phloem translocation in angiosperms is best explained by which method?

#Question id: 10920

#Unit 6. System Physiology – Plant

The pressure-flow model, first proposed by Ernst Münch, Phloem loading at the source and phloem unloading at the sink establish the pressure gradient.

a.) In source tissues, an accumulation of sugars in the sieve elements generates a lower or negative solute potential (ψs).

 b.) source tissue, causes a steep drop in the water potential (ψ), due to water potential gradient, water enters the sieve elements and causes turgor pressure (ψp ) decrease.

c.) In sink tissues, phloem unloading leads to a lower sugar concentration in the sieve elements, generating a higher or less negative solute potential.

d.) As the water potential of the phloem rises above that of the xylem, water tends to leave the phloem in response to the water potential gradient, causing a decrease in turgor pressure in the sieve elements of the sink.

Which of the following statements of sink and source tissue is FALSE?

#Question id: 10919

#Unit 6. System Physiology – Plant

Both of these observations—________X__________and________Y__________—support the existence of mass flow in the sieve elements of the phloem.

#Question id: 10918

#Unit 6. System Physiology – Plant

The import into sinks such as developing roots, tubers, and reproductive structures, In many ways the events in sink tissues are simply the reverse of the events in sources. The following steps are involved in the import of sugars into sink cells such as;

#Question id: 10386

#Unit 6. System Physiology – Plant

 During light-regulated plant development many seeds require light to germinate, a process called