A plant sheds 5000 pollen grains at the two-celled stage…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A plant sheds pollen grains at the two-celled stage. Pollen of a second plant is shed at the three-celled stage, and a sample of grains is taken from it.
- How many cells are in the first sample?
- How many cells are in the second sample?
- How many male gametes will the first sample form after every grain has germinated?
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. grains in each sample.
Plan. Count the cells in one grain of each kind.
Step 1. The first sample. cells.
Step 2. The second sample. cells.
Step 3. The male gametes. Each generative cell divides into two male gametes. There are of them, so male gametes.
Answer: ; ; .
Check. The second sample has already made its male gametes, so its cells are vegetative cells and gametes.
Watch out. The generative cell divides in the pollen tube, not in the anther.
More onPlant Biology
Discussion (0)
Log in to join the discussion.
Loading…