Question

Cell wall is absent in?
A. Mycoplasma
B. Gametes
C. Animal cells
D. All of the above

Answer 1

Hint: A cell wall is a structural layer that surrounds some types of cells. It is present just outside the cell membrane. It is tough, flexible, and sometimes rigid. It is present in most prokaryotes (except mollicute bacteria), in algae, fungi, and eukaryotes including plants. It is absent in animals. A major function is that they prevent over-expansion of the cell when water enters.

Complete answer:
Option A- Mycoplasma
Mycoplasma is a genus of bacteria. It lacks a cell wall around their cell membranes. Due to this characteristic, they are naturally resistant to antibiotics that target cell wall synthesis, for example- beta-lactam antibiotics. They can be parasitic or saprotrophic.

Option B- Gametes
Gametes are reproductive cells of organisms. They are also known as sex cells. Female gametes are known as ova or egg cells, and male gametes are known as sperm. Gametes are haploid cells as each cell carries only one copy of each chromosome.

Option C- Animal cells
As the name indicates, an animal cell is a type of cell that is seen primarily in animal tissues. It is characterized by the absence of a cell wall and cell organelles enclosed only within the cell membrane.

Option D- all of the above
All of the above means Mycoplasma, gametes, and animal cells. They all lack cell walls around their plasma membrane.

So, the correct answer is option D- all of the above.

Note: The cell wall surrounds the plasma membrane of plant cells. They provide tensile strength and protection against mechanical and osmotic stress. It also enables cells to develop turgor pressure (the pressure of the cell contents against the cell wall).