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

#Question id: 4757

#Unit 8. Inheritance Biology

The newborn baby of a mother having blood group O, Rh+ and father having blood group AB, Rh-, got mixed with other babies in the hospital. The baby with which of the following blood groups is not confirmable to be of the said couple?

(i) AB, Rh+                                                    (ii) O, Rh+

(iii) A, Rh+                                         (iv)  B, Rh+

#Question id: 4758

#Unit 8. Inheritance Biology

The allele l in human population is recessive lethal and x chromosome linked. If a female is heterozygous for l allele marries with normal male. What will be interpretation correct?

#Question id: 4759

#Unit 8. Inheritance Biology

which of the following is not a mechanism for sex determination?

#Question id: 4760

#Unit 8. Inheritance Biology

you set up a cross between true breeding wild type male fruit flies and true breeding female flies with a yellow body color. you notice in the f1 generation that half the flies, specifically all the males, have yellow body color while the females are wild type (gray). which of the following explanations is the most likely?

#Question id: 4761

#Unit 8. Inheritance Biology

which of the following statements about a lethal allele is not correct?

#Question id: 4762

#Unit 8. Inheritance Biology

a semilethal allele is an example of which of the following extensions of mendelian genetics?