VBQs Class 12 Biology Human Reproduction

Please refer to VBQs for Class 12 Biology Human Reproduction. All value based questions for Biology Class 12 have been provided with solutions. We have provided below important values questions and answers. Students should learn these solved VBQs for Class 12 Biology as these will help them to gain more marks and help improve understanding of important topics.

Human Reproduction VBQs Class 12 Biology with Answers

Very Short Answer Type Questions

Question. List different parts of human oviduct through which the ovum travels till it meets the sperm for fertilization. 
Answer : Fimbriae, infundibulum, ampulla and ampullaryisthmic junction. 

Question. Write the function of Seminal vesicle.
Answer : Seminal vesicle produces an alkaline secretion.
It neutralizes the acidic environment of female reproductive tract and male urethra during coitus.

Question. Give reasons for the following :
The human testes are located outside the abdominal cavity.
Answer : For spermatogenesis, it is essential to maintain the temperature 2-2.5°C lower than normal internal body temperature. 

Short Answer Type Questions

Question. Write the location and functions of myometrium and endometrium.
Answer : Myometrium : Middle layer of uterus, contractions of the uterus during delivery/child birth/parturition. 
Endometrium : Inner layer of uterus, cyclic changes during menstruation/implantation of embryo.

Question. Why are the human testes located outside the abdominal cavity ? Name the pouch in which they are present. 
Answer : Testes are located outside the abdominal cavity within a sac called scrotal sac or scrotum. Scrotum the body temperature. The lower temperature is required for proper functioning of testes and for spermatogenesis. 

Question.

The above diagram shows human male reproductive system (one side only).
(i) Identify ‘X’ and write its location in the body.
(ii) Name the accessory gland ‘Y’ and its secretion.
(iii) Name and state the function of Z.
Answer : (i) X — Testicular lobules, location : Testis, outside the abdominal cavity scrotum.
(ii) Y — Seminal vesicle, seminal plasma.
(iii) Z — Epididymis, function : Storage of sperms.
Detailed Answer :
(i) X- is testicular lobules found in testis. The testes are located outside the abdominal cavity within
a pouch like structure called ‘scrotum’.
(ii) The accessary gland Y is seminal vesicle. It produces an alkaline secretion called seminal
fluid which forms 60–70% of semen by volume.
(iii) Z is epididymis. It stores sperm and also it secretes fluid containing the nutrients required
for the maturation of spermatozoa.

Question. Name the male accessory glands in humans and write their functions.
Answer : (Paired) seminal vesicles, prostate, bulbourethral glands (paired) 
Functions : Secretions constitute the seminal plasma, which is rich in fructose / calcium and certain enzymes, lubrication of penis 
Detailed Answer :
Male accessory glands include a pair of seminal vesicle, prostate and paired bulbourethral glands (cowper’s glands.)
Functions :
(i) Seminal Vesicles : Produce seminal fluid which forms 60 – 70% of semen. The fluid activates the sperms and have fructose, citrate, inositol and proteins for nutrition of sperms.
(ii) Prostate Gland : The gland secretes thin, milky and alkaline secretion which neutralises the acidic secretion in female vagina.
(iii) Cowper’s Gland (Bulbourethral gland) : Helps in secretion of mucus which lubricates urinogenital tract.

Question.

The above diagram shows a part of the human female reproductive system.
(i) Name the gamete cells that would be present in ‘X’ if taken from a newborn baby.
(ii) Name Y and write its function.
(iii) Name Z and write the events that take place here.
Answer : (i) X = Primary oocytes
(ii) Y = Fimbriae, collection of ovum
(iii) Z = ampullary – isthmic junction/fallopian tube, the ovum encounters the sperms/ fertilization takes place.

Question. Name and explain the role of inner and middle walls of the human uterus.
Answer : Inner : Endometrium. 
Supports foetal growth, helps in placenta formation after implantation. 
Middle : Myometrium.
Exhibits strong contraction during delivery of baby.
Detailed Answer:
The inner wall of uterus is called as endometerium.
It is involved in cyclic changes during menstruation and implantation of embryo.
The middle wall of the uterus is called myometrium.
It is involved in strong contractions during delivery of baby.

Question. Give a schematic representation, showing the events of spermatogenesis in human male.
Answer : 

Question. (i) Draw a diagram of the structure of a human ovum surrounded by corona radiata. Label the following parts :
(a) Ovum
(b) Plasma membrane
(c) Zona pellucida.
(ii) State the function of Zona pellucida.
Answer : (i)

(ii) Function of zona pellucida : It is a glycoprotein layer surrounding the plasma membrane. It ensures that only one sperm can fertilize an ovum, because it induces certain changes in the membrane which block the entry of other sperms into the ovum just after fusion.