Question

The infolds of plasma membrane in bacteria cells are known as
a. Episomes
b. Mesosomes
c. Spherosomes
d. Acrosomes

Answer 1

Many heterotrophic bacteria contain intracellular membranes. These membranes are in the form of tubules or sheets and are physically divided into compartments. The process of respiration and secretion of enzymes takes place in these infolds.

Complete answer:

Option A:
Episome is a genetic determinant that replicates automatically in the bacterial cytoplasm. This can be seen in plasmids as they are one of the examples. Episomes can get attached to the bacterial cell membrane and become integrated into chromosomes.

Option B:
Mesosomes are seen in mitochondria of eukaryotic cells. It is the infolding of the bacterial cell membrane. It helps in increasing the surface area and also helps in secreting enzymes and in respiration. These are usually seen in the nuclear area and near the site of cell division.

Option C:
Spherosomes take part in the synthesis of lipids and are storage zones in the cell. They contain some proteins too. They are small spherical organelles and are bounded by a single membrane. They are also known as plant lysosomes and they develop from the endoplasmic reticulum.

Option D:
In the anterior half of the head of sperm cells in many animals including humans, the Acrosomes are found. It is a cap-like structure that is derived from the Golgi apparatus. It helps in digesting the coating of the egg cell.

Hence, the correct answer is option (B).

Note: The mesosomes represent the physical compartmentation of the bacterial cell. They are a tube-like structure called vesicles. The function and structure of the mesosome are not yet known. The protein of the mesosomes differs from that in the cell membrane.