Question

Human spermatozoa:

Answer 1

Answer:

a. will contain either a Y chromosome or a X chromosome but not both.

Explanation:

There are two types of human spermatozoa, the x-chromosome carriers (female) and the y-chromosome carriers (male). However, a sperm will never have both chromosomes at once.

Thus, if the egg is fertilized by an x-chromosome, the result will be a girl. Otherwise, if fertilized by a y-chromosome, it will be a boy.

The sperm is formed by a head and tail. In the flat egg-shaped head we have the nucleus that houses the genetic material. This region is responsible for the transmission of paternal hereditary characters. The tail (or flagellum) is divided into three parts: intermediate part, main part and end piece. It facilitates the locomotion of the male sexual gamete to the egg.

Answer 2

Answer:

a. will contain either a Y chromosome or a X chromosome but not both.

c. reach maturity in the seminal vesicles.

d. contain enzymes in their heads which facilitate penetration of ovum.

Explanation:

Spermatogenesis is a complicated process. It occurs in the seminiferous tubule / seminal vesicle of the testis. The spermatogenesis occurs in 2 steps. In the first step, spermatids are produced. In the second 2nd step, spermatids undergo metamorphosis and form spermatozoa.  

The process of formation of spermatozoa is known as spermatogenesis. These are formed from the primary germ cells of the testis. It occurs in 3 phases- multiplication phase, growth phase, and maturation phase.  

The maturation phase is important. Here primary spermatocyte divides 2 times. The first division is a meiotic division that produces 2 haploid cells, called secondary spermatocytes.  

The second division is a mitotic division.  Thus from 2 secondary spermatocytes, 4 spermatids are formed. Further by metamorphosis, the spermatids result in spermatozoa. The spermatozoa have 4 parts - head, neck, middle piece, and a tail. The head is a conical shape. It consists of a nucleus and acrosome.

Acrosome is also called head cap. It secretes a tissue dissolving enzyme which helps  to rupture the egg cell. Thus the sperm can penetrate the ovum.