Which one of the following organelles is not found in animal cells?

Which one of the following organelles is not found in animal cells?

Cell membrane
Endoplasmic reticulum
Cell wall
Lysosome
This question was previously asked in
UPSC CAPF – 2021
The question asks which of the listed organelles is *not* found in animal cells. Let’s review each option:
A) Cell membrane: The cell membrane is the outer boundary of animal cells and is present in all eukaryotic cells, including plant cells (where it is inside the cell wall).
B) Endoplasmic reticulum: The endoplasmic reticulum (ER) is a network of membranes involved in protein synthesis (rough ER) and lipid synthesis (smooth ER). It is found in both animal and plant cells.
C) Cell wall: The cell wall is a rigid outer layer that provides structural support, protection, and shape to the cell. Cell walls are present in plant cells (made primarily of cellulose), fungi, bacteria, and some protists, but they are *absent* in animal cells.
D) Lysosome: Lysosomes are membrane-bound organelles containing digestive enzymes. They are primarily found in animal cells, where they are involved in breaking down waste materials and cellular debris. While some plant cells may have vacuoles with lytic activity similar to lysosomes, dedicated lysosomes as found in animal cells are generally considered absent in plant cells. However, the cell wall is definitively absent in animal cells, making it the correct answer.
– Recall the key organelles found in typical animal and plant cells.
– Note the distinguishing features between plant and animal cells, such as the presence of a cell wall, chloroplasts, and large central vacuoles in plants, and lysosomes and centrioles typically in animals.
– The cell wall is a defining feature of plant cells that is absent in animal cells.
Other organelles typically found in animal cells but not in plant cells include centrioles. Organelles typically found in plant cells but not in animal cells include cell walls (as mentioned), chloroplasts, and often a large central vacuole. Both cell types have cell membranes, nuclei, mitochondria, endoplasmic reticulum, Golgi apparatus, and ribosomes.