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

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#Question id: 59

#SCPH05 I Biotechnology

Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?

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#Question id: 15213

#SCPH28 | Zoology

In SDS PAGE chloride ions and glycinate ions are used to create

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#Question id: 3054

#SCPH05 I Biotechnology

A pure culture in exponential growth phase has a bacterial concentration of 6.4 x 10^8 cells/ml. If the bacterium has a generation time of 1 h, how long ago was the cell concentration 8.0 x 10^7 cells/ml?

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#Question id: 4133

#SCPH05 I Biotechnology

Which of the following statements about aminoacyl-tRNA synthetases is false?

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#Question id: 19775

#SCPH05 I Biotechnology

Which experimental observation correctly account for the phenomenon?

Experimental observation                                 Phenomenon

(A) X-rays spectra                                              Charge on nucleus

(B) alpha -particle scattering                           Quantized electron orbit .

(C) Photoelectric effect                                      The nuclear atom

(D) Emission spectra                                         Quantization of energy.