The PEN divides by mitosis, and every nucleus divides in each round…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
The PEN divides by mitosis, and every nucleus divides in each round. No cell walls form at this stage.
- How many nuclei are there after rounds?
- How many nuclei are there after rounds?
- What is the least number of rounds after which there are more than nuclei?
Need a reminder? The key ideaShow
One male gamete fuses with the egg and makes the zygote, . The other fuses with the two polar nuclei and makes the primary endosperm nucleus (PEN), . The two polar nuclei and the egg come from the same megaspore, so they are alike, and the two male gametes are alike. The PEN divides by mitosis, first with free nuclei and later with walls.
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. One nucleus at the start. The number doubles in each round.
Plan. After rounds there are nuclei.
Step 1. Five rounds. nuclei.
Step 2. Eight rounds. nuclei.
Step 3. More than 1000. is too small, and is more than . So rounds.
Answer: ; ; rounds.
Check. and .
Watch out. The number of nuclei doubles, so it grows much faster than the number of rounds.
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