(a) Draw a labelled diagrammatic view of human male reproductive system.

(b) Differentiate between :

(i) Vas deferens and vasa efferentia

(ii) Spermatogenesis and spermiogenesis

OR

(a) Explain the phenomenon of double fertilization.

(b) Draw a labelled diagram of a typical anatropous ovule.

(a) The human male reproductive system is located in the pelvis region and includes a pair of testes along with accessory ducts (rete testis, vasa efferentia,epididymis and vas deferens), glands (paired seminal vesicles, a prostate and pair of bulbourethral glands) and external genitalia.

The diagrammatic view of the human male reproductive system is as follows:

(b)

i) The differences between vas deferens and vas efferentia are:

This diagram shows the location of vas deferens and vas efferentia.

ii) The differences between Spermatogenesis and spermeogenesis are:

This diagram shows the seminiferous tubule and in this diagram one can see the spermatids and the spermatozoa.

OR

(a)

The process by which one male gamete fuses with the egg along with the union of the second male gamete with the secondary nucleus is called double fertilisation.

One of the male gametes moves towards the egg cell and fuses with its nucleus to complete the process called syngamy. It gives rise to a diploid cell called the zygote.

The nucleus of the second male gamete moves towards the two polar nuclei and fuses with them to form a triploid primary endosperm nucleus (PEN). In this process, as three haploid nuclei fuse, it is called triple fusion. Since two types of fusions (syngamy and triple fusion) are taking place in an embryo sac, this process is termed as double fertilisation, a process which is unique to flowering plants.

This diagram shows a fertilized embryo sac containing the zygote and the primary endosperm nucleus.

(b) A diagram of a typical anatropous ovule is as follows:

The anatropous ovule is a type of ovule (the reproductive part of a female flower) which is inverted in shape and its micropyle lies close towards the funicle such that the ovule is turned back 180 degrees on its stalk.