Science Lesson Plan: Structure and Function of a Cell Nucleus

The Nucleus

Before beginning this lesson plan, remind students that only eukaryotic cells have a nucleus and belong to multicellular organisms. For this lesson plan you will need a hard boiled egg and a napkin for each student. Follow the instructions below to teach your students about the structure and function of a cell nucleus.

1. Give each student an egg an a napkin. Ask students not to break the egg open just yet.
2. Instruct students to take out a pencil and piece of paper to write down the parts of the nucleus as you talk about them.
3. Instruct students to look closely at the egg and feel how the egg is not entirely smooth.
4. Talk about the fact that eggs should be clean if they are to be eaten because the shell is actually porous, hence the lack of smoothness. This porousness allows the egg to absorb things that are on the shell. This is similar to the way a nuclear envelope works on a nucleus. If the egg were to be dropped in a bowl of water, it would be separated from the water by this nuclear envelope, much the way a nucleus is separated from the cytoplasm of a cell. The nuclear envelope also has pores so that it can allow proteins inside the nucleus and ribosomal subunits to escape the nucleus.
5. Ask students to peel the shell off of the egg. Ask them to imagine that the white of the egg is similar to the chromatin of the nucleus. Explain that the chromatin holds the DNA and proteins for the nucleus. It coils to form chromosomes that are needed for cell division.
6. Ask students to peel the white part of the egg away from the yolk of the egg. Explain that the yolk of the egg represents the nucleolus of the nucleus. Inform students that this is not actually a separate structure from the chromatin, rather it is the area where the nucleoli come together to form ribosomal RNA or “rRNA”. This is where the joining of the rRNA and the proteins join to form the subunits of ribosomes.

In short, students should be made to understand that without the nucleus, eukaryotic cells would not be able to reproduce. The nucleus is essentially the brain center of the cell where genetic material and metabolic functioning are regulated.