In our society the women are often blamed for giving birth to daughters. Can you explain why this is not correct?
The sex chromosome pattern in the human females is XX and that of male is XY. Therefore, all the haploid female gametes (ova) have the sex chromosome X, however, the haploid male gametes have either X or Y. Thus 50% of sperms carry the X-chromosome while the other 50% carry the Y-chromosome. After fusion of the male and female gametes, the zygote carries either XX or XY depending upon whether the sperm carrying X or Y fertilizes the ovum. The zygote carrying XX would be a female baby and XY would be a male baby. That is why it is correct to say that the sex of the baby is determined by the father.
Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?
A human female experiences two major changes, menarche and menopause during her life. Mention the significance of both the events.
The mother germ cells are transformed into a mature follicle through series of steps. Provide the missing steps in the blank boxes.
Match the following and choose the correct options:
Options:
(a) A—ii, B—i, C—iii, D—iv (b) A—iii, B—iv, C—ii, D—i
(c) A—iii, B—i, C—ii, D—iv (d) A—ii, B—iv, C—iii, D—i
Give the names and functions of the hormones involved in the process of spermatogenesis. Write the names of the endocrine glands from where they are released.
During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring. What are the processes through which these events take place?
Female reproductive organs and associated functions are given below in column A and B. Fill in the blank boxes.
In our society the women are often blamed for giving birth to daughters. Can you explain why this is not correct?
What role does pituitary gonadotropins play during follicular and ovulatory phases of menstrual cycle? Explain the shifts in steroidal secretions.
(a) How many spermatozoa are formed from one secondary spermatocyte? (b) Where does the first cleavage division of zygote take place?
What is the significance of ampullary-isthmic junction in the female reproductive tract?
How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?
Name the functions of the following:
(a)Corpus luteum (b) Endometrium
(c)Acrosome (d) Sperm tail
(e) Fimbriae
Corpus luteum in pregnancy has a long life. However, if fertilisation does not take place, it remains active only for 10-12 days. Explain.
From where the parturition signals arise”mother or foetus? Mention the main hormone involved in parturition.
How many eggs do you think were released by the ovary of a female dog which gave birth to 6 puppies?
During reproduction, the chromosome number (2n) reduces to half (n) in the gametes and again the original number (2n) is restored in the offspring. What are the processes through which these events take place?
What are the events that take place in the ovary and uterus during follicular phase of the menstrual cycle?
Match between the following representing parts of the sperm and their functions and choose the correct option.
Options:
(a) A”ii, B”iv, C”i, D”iii
(b) A”iv, B”iii, C”i, D”ii
(c) A”iv, B”i, C”ii, D”iii
(d) A”ii, B”i, C”iii, D”iv
Given below are the events in human reproduction. Write them in correct
sequential order: Insemination, gametogenesis, fertilisation, parturition, gestation, implantation
Fill in the blanks:
(a)Humans reproduce————— (asexually/sexually).
(b)Humans are————— (oviparous, viviparous,ovoviviparous).
(c)Fertilization is————— in humans (external/internal).
(d)Male and female gametes are—————(diploid/haploid).
(e)Zygote is————— (diploid/haploid).
(f)The process of release of ovum from a mature follicle is called————— .
(g)Ovulation is induced by a hormone called—————
(h)The fusion of male and female gametes is called————— .
(i)Fertilization takes place in—————
(j)Zygote divides to form————— which is implanted in uterus.
(k)The structure which provides vascular connection between foetus and uterus is called————— .
Identify True/False statements. Correct each
false statement to make it true.
(a)Androgens are produced by Sertoli cells. (True/False)
(b)Spermatozoa get nutrition from sertoli cells. (True/False)
(c)Leydig cells are found in ovary. (True/ False)
(d)Leydig cells synthesize androgens. (True/ False)
(e)Oogenesis takes place in corpus luteum. (True/False)
(i) Menstrual cycle ceases during pregnancy. (True/False)
(g) Presence or absence of hymen is not a reliable indicator of virginity or sexual – experience. (True/False)
What are the changes in the oogonia during the transition of a primary follicle to Graafian follicle?
