Question

Give a short description of homogametes and heterogametes with examples.

Answer 1

Hint: We all know that the male gamete fuses with the female gamete to give rise to a zygote. The two gametes are quite different from each other. From the words homo and hetero. We know that homo stands for same or similar while hetero stands for different.

Complete answer:
Homogametes are those gametes which bear morphological and anatomical resemblance with each other. Heterogametes are those gametes which are very different from each other.

The male gamete in humans is known as the sperm while the female gamete is known as the ovum or the egg. This sperm fertilizes the ovum to form a zygote which further develops into an embryo.

Now both the male and the female gametes are morphologically and anatomically different from each other. The shape of the sperm is somewhat elongated. It has a head, a midpiece and a tail. The head bears acrosomal vesicle which has an enzyme hyaluronidase. This enzyme helps the sperm penetrate the ovum.

Further, the female gamete or the ovum is circular in shape. It is surrounded by a layer known as the zona pellucida. Outside the zona pellucida are cells which are a part of corona radiata.

Since, the sperm and the ovum are different in shape and structure, hence they are heterogametes. Homogametes are found in the Ulothrix and Rhizopus.

Note: Here it must be noted that the homogametes are also known as the isogametes. They are so much similar to each other that it becomes quite difficult to differentiate between the two. Moreover, in heterogametes the female gamete is usually immotile while the male gamete is usually motile.