Read these descriptions of the parts of an ovule…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Read these descriptions of the parts of an ovule.
- A small opening at the tip of the integuments.
- The mass of cells with reserve food, inside the integuments.
- The place where the funicle meets the body of the ovule.
- The end of the ovule opposite to the opening.
Name each part. Then say in which of the four the embryo sac lies.
Need a reminder? The key ideaShow
An ovule has one megaspore mother cell (MMC), which is diploid. The MMC divides by meiosis into four haploid megaspores. In most plants, one is functional and three degenerate. The functional megaspore divides by mitosis three times, with no walls, to make 8 nuclei. The mature embryo sac has 7 cells: the egg, 2 synergids, 3 antipodals and the central cell with 2 polar nuclei.
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. Four descriptions.
Plan. Match each description with the part.
Step 1. The opening. The micropyle.
Step 2. The mass of cells. The nucellus.
Step 3. The junction. The hilum.
Step 4. The opposite end. The chalaza.
Answer: (a) micropyle; (b) nucellus; (c) hilum; (d) chalaza. The embryo sac lies in the nucellus.
Watch out. The micropyle and the chalaza are at opposite ends. The egg apparatus is near the micropyle.
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