Q28 of 30 Page 1

(i) Describe the various steps involved in the process of binary fission with the help of a diagram.

(ii) Why do multicellular organisms use complex way of reproduction?


OR


(i) Describe the role of prostate gland, seminal vesicle and testes in the human male reproductive system.


(ii) How is the surgical removal of unwanted pregnancies misused?


(iii) Explain the role of oral contraceptive pills in preventing conception.


(i) The various steps involved in the process of binary fission with the help of a diagram are:

Binary fission takes place in a particular orientation. During this process, an organism duplicates its genetic material, and then divides into two parts by the process of cytokinesis. Then each new organism formed after binary fission receives one copy of DNA.



(ii) Multicellular organisms cannot use simpler way of reproduction because they are not made of a single cell but of multiple cells which are organized into tissues which further forms organs and that further forms organ system so their whole functioning is complex. Simple asexual means would not be able to produce a progeny with genetic variation. Due to this fact, multicellular organisms need to use a complex way of reproduction.


OR


(i) The role of prostate gland, seminal vesicle and testes in human male reproductive system are as follows-


i) Prostate gland: It secretes the prostate fluid which is one of the major components of semen.


ii) Seminal vesicle: It stores and produces the majority of the fluid that is responsible for making up the semen. It is also responsible for sperm motility. Hence it is important for fertility.


iii) Testes: It secretes the male hormone, testosterone and produces the gametes or sperms in the seminiferous tubules.



(ii) The Medical Termination of Pregnancy (MTP) or Abortion is a procedure where the unwanted foetus is surgically removed. It has been used widely in the conditions where the pregnancy, if continued might cause harm to the mother or the foetus has some life-threatening genetic disease.


But it is also being misused for aborting the girl child i.e. Female Foeticide. Due to several myths and misconceptions, the female child is believed to be a burden on the family in our society, which is far from truth. Hence, people opt for Pre-natal sex determination followed by Abortion if the sex of the foetus turns out to be Female. Hence, both Pre-natal sex determination and Female Foeticide has been banned by our Government.


(iii) Oral contraceptives are usually small doses of either progestogens or progestogen–estrogen used in the form of pills. Pills are taken daily for 21 days starting within the first five days of the menstrual cycle. After a gap of 7 days, it has to be repeated in the same pattern. These pills inhibit ovulation, implantation and change the cervical mucus to obstruct entry of sperms.


More from this chapter

All 30 →
26

The formulae of four organic compounds are given below:


(i) Which one of these compounds A, B, C or D is a saturated hydrocarbon?


(ii) Identify the organic acid and give its structural formula.


(iii) Which ofthe above compounds when heated at 443K in the presence of concentrated forms ethene as the major product? What is the role played byconcentrated in this reaction? Also write the chemical equationinvolved.


(iv) Give a chemical equation when B and C react with each other


in presence of concentrated. Name the major product formed andmention one of its important use.


27


(i) Identify any two parts from the above diagram which carry oxygenated and deoxygenated blood.


(ii) Explain the process of double circulation with the help of a flow chart


29

(i) Consider a conductor of resistance ‘R’, length ‘L’, thickness’ d’ and resistivity ‘ρ’. Now this conductor is cut into four equal parts. What will be the new resistivity of each of these parts? Why?

(ii) Find the resistance if all of these parts are connected in:


(a) Parallel


(b) Series


(iii) Out of the combinations of resistors mentioned above in the previous part, for a given voltage which combination will consume more power and why?


30

(i) A lens produces a magnification of -0.5. Is this a converging or diverging lens? If the focal length of the lens is 6 cm, draw a ray diagram showing the image formation in this case.

(ii) A girl was playing with a thin beam of light from a laser torch by directing it from different directions on a convex lens held vertically. She was surprised to see that in a particular direction, the beam of light continues to move along the same direction after passing through the lens. State the reason for her observation. Draw a ray diagram to support your answer.


OR


(i) On entering in a medium from air, the speed of light becomes half of its value in air. Find the refractive index of that medium with respect to air?


(ii) A glass slab made of a material of refractive index n1 is kept in a medium of refractive index n2.


A light ray is incident on the slab. Draw the path of the rays of light emerging from the glass slab, if (i) n1> n2 (ii) n1 = n2 (iii) n1< n2