The pollen mother cell of maize has 20 chromosomes…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The pollen mother cell of maize has chromosomes.
- How many chromosomes has each microspore?
- How many chromosomes are in all the nuclei of one three-celled pollen grain taken together?
- How many chromosomes are in the four cells of one microspore tetrad taken together?
Need a reminder? The key ideaShow
A pollen mother cell (PMC) is diploid, with chromosomes. It divides by meiosis into four haploid microspores, with chromosomes each. Each microspore divides by mitosis into a vegetative cell and a generative cell. The generative cell divides by mitosis into two male gametes. Mitosis keeps the chromosome number.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Given. PMC: .
Plan. Find , then count the nuclei.
Step 1. A microspore. chromosomes.
Step 2. A three-celled grain. It has a vegetative nucleus and two male gametes. Each has chromosomes, so .
Step 3. The tetrad. Four microspores of each make .
Answer: ; ; .
Check. The tetrad holds chromosomes, which is twice the of the PMC, because each of the chromosomes was copied before meiosis.
Watch out. Do not halve the number again at the mitoses.
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