Gametogenesis

1 Mark Questions

1. When do the oogenesis and the spermatogenesis initiate in human females and males, respectively?[Delhi 2012]

Ans. Oogenesis initiates in foetal or embryonic

stage of females, whereas spermatogenesis, in males starts at puberty.

2.Mention the differences between spermiogenesis and spermiation.[Delhi 2012] Ans. Difference between spermiogenesis and spermiation is:

Spermiogenesis Spermiation It is the process of Sperms get attached to transforming Sertoli cells to draw spermatids into nourishment and finally mature released from spermatozoa or seminiferous tubules by sperms. the process called spermiation.

1. Where is acrosome present in humans? Write its function. [All India 2012]

Ans. In humans, the acrosome is present in the anterior portion of head of the human sperm. Function Enzymes present in acrosome help in contact and penetration into egg, during fertilisation of the ovum

4.List the changes the primary oocyte undergoes in the tertiary follicular stage in human embryo.[Foreign 2011]

Ans. In human embryo, the primary oocyte grows in size, completes meiosis-I and forms a larger cell, the secondary oocyte and a smaller cell, the first polar body.

2 Marks Questions

1. Write the effect of high concentrations of LH on a mature Graafian follicle. [All India 2014]

Ans. The high concentration of LH induces the rupture of Graafian follicle which results in release of secondary oocyte and thus causing ovulation in females.

6.Differentiate between

(i)Vas deferens and vasa efferentia

(ii)Spermatogenesis andspermiogenesis. [Delhi 2014]

Ans.

(i) Differences between vas deferens and vasa efferentia are:

Vas deferens Vasa efferentia

It is a tube-like structure It connects the rete

which conducts the testis to spermatozoa from the epididymis. (1)

epididymis to penis.

(ii) Differences between spermatogenesis

and sperimiogenesis are:

Spermatogenesis Sperimiogenesis It is a process of It is a process of formation of sperms transformation of a from immature germ circular spermatid to a cells. motile spermatozoa. (1/2) Number of cells No change in number of increased as each cells as only one spermatogonium spermatid develops into produces four a spermatozoa. (1/2)

spermatids.