The structure present in both plant and yeast cells but not in a bacterial cell is the nucleus.
Explanation
- Both plant and yeast cells are eukaryotic cells, meaning they have a membrane-bound nucleus that contains their genetic material (DNA).
- Bacterial cells are prokaryotic and lack a true nucleus; their DNA floats freely in the cytoplasm without a surrounding membrane.
- The nucleus controls cell activities such as gene expression, growth, and reproduction in plant and yeast cells, which is absent in bacteria.
Additional Differences
- Plant and yeast cells have other membrane-bound organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum, which bacteria do not have.
- While all three have cell walls, the composition differs: plant cell walls are made of cellulose, yeast cell walls mainly contain chitin, and bacterial cell walls contain peptidoglycan.
Thus, the presence of a nucleus is a key structure distinguishing plant and yeast cells from bacterial cells.