Video Transcript
Microspores divide to produce
pollen grains. By which process do spore mother
cells form microspores? (A) Mitosis, (B) meiosis, (C)
transcription, or (D) translation.
This question asks us about the
formation of pollen grains, which contain the male gamete of flowering plants. To understand how these pollen
grains are formed, we first need to investigate how spore mother cells are converted
into structures called microspores, which eventually divide to form these male
gametes.
Pollen grains are produced in the
flowers’ anthers, each of which usually contains four sacs filled with pollen grains
when fully mature. Before these pollen grains are
formed during flower development, these sacs are filled with large diploid cells
called spore mother cells. Remember, a diploid cell is one
that has a full set of chromosomes, often represented as 2n.
You might recall that gametes are
haploid cells, which means that they contain half the number of chromosomes of a
typical body cell, often represented as n. Microspores, which eventually form
the male gametes, are also haploid.
So what process halves the number
of chromosomes in a cell that allows these diploid spore mother cells to be
converted into haploid microspores? Meiosis is a process that halves
the number of chromosomes in a cell, as it is a special type of cell division where
one cell divides twice to form four haploid cells.
Now we know the correct answer to
this question. The process by which spore mother
cells form microspores is (B), meiosis.
