A botanist is studying microsporogenesis and microgametogenesis in an angiosperm species that sheds its pollen at the 3-celled stage. To generate exactly 100 such mature pollen grains, the total number of meiotic and mitotic divisions that must occur in the anther is:

Step-by-step solution

One microspore mother cell undergoes one meiotic division to produce four haploid microspores. To produce 100 microspores, the number of meiotic divisions required is 100 4 = 25 . Each microspore develops into a pollen grain. For the pollen to be shed at the 3 -celled stage, the microspore undergoes two mitotic divisions. The first mitotic division produces a vegetative cell and a generative cell. The second mitotic division occurs in the generative cell to produce two male gametes. Since each of the 100 microspore