Question

Which of the following statements about pollen and pollination is false?

• A. Evolution of the pollen grain rejected the need for swimming sperm in flowering plants
• B. At maturity, the pollen grain consists of two sperm nuclei and a tube nucleus
• C. The pollen tube enters the female gametophyte through the style
• D. The pollen grain makes twice the genetic contribution to endosperm cells than it does to the cells of the embryo

Answer 1

The correct option is D The pollen grain makes twice the genetic contribution to endosperm cells than it does to the cells of the embryo

A fertilized egg develops into a sporophyte embryo. While some primitive gymnosperms have flagellated sperm cells, the sperm in most gymnosperms and all angiosperms lack flagella. In seed plants, the use of resistant, far-traveling, airborne pollen to bring gametes together is a terrestrial adaptation. So the statement of option A is correct.

But the endosperm has a diploid nucleus and the pollen grain has two male -haploid gametes, so the overall gene contribution of the endosperm and the pollen grain is equal.

So the correct answer should be option D, The pollen grain makes twice the genetic contribution to endosperm cells than it does to the cells of the embryo.