Ncrt biology 0 notes ch how do organisms reproduce
Answers
NCERT IN-TEXT QUESTIONS SOLVED
Q1. What is the importance of DNA copying in reproduction?Ans. DNA copying is an important phenomenon of reproduction through which the organisms pass on their characteristics to their offspring. It maintains the characteristics in different generations of the species. It also produces variations which are useful for the survival of species for long time.
Q2. Why is variation beneficial to the species but not necessary for the individual?Ans. Accumulation of variations after several generations results in new set of traits required for survival. As they show results after many generations so they are not important for individual.
Q3. How does binary fission differ from multiple fission?Ans. Binauy Fission: An organism is divided into two individuals. Mitotic division takes place resulting in two identical individuals or daughter cells. e.g., Amoeba. Multiple Fission: Mitotic division takes place. The nucleus a ii diumrepeatedly to form a number of equal sized and similar individuals, e.g.,
Q4. How will an organism be benefited if it reproduces through spores?Ans. During adverse circumstances spore remain coated are means po tideve over layer. This helps an organism survive adverse conditions. Spores are means to tide over bad phases.
Q5. Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?Ans. More complex organisms cannot give rise to new individuals because: 1. Their body design is highly complicated. 2. There are specific organs to do specific functions. 3. There is a labour division in the body of complex organisms. 4. Exception is lizard, which can regenerate its tail.
Q6. Why is vegetative propagation practised for vowing same types of plants?Ans. The process by which some plant can reproduce asexually It has their vegetative pars like roots, stems and leaves is called vegetative propagation. Plants raised by this method can befit flowers and fruits earlier than those produced from seeds. Plants that have lost capability to produce seeds like banana, organge, rose and jasmine can be propagated. All plants produced are genetically similar to the parent plant.
Q7. Why is DNA copying an essential part of the process of reproduction?Ans. DNA copying is needed because information stored in DNA is used to e make protein. Synthesis of different proteins will lead to altered body design. Thus, reproduction at its most basic level involves making copies of the blueprints of body design.
Q8. How is the process of pollination different from fertilization?Ans. Pollination is the transfer of pollen grains from the anther of a stamen to the stigma of a carpel. These are transferred by agents such as insects, birds, wind or water. Fertilization is defined as the fusion of a mele gamete (sperm) with a female gamete (ovary) to form a zygote by sexual reproduction.
Q9. What is the role of seminal vesicles and prostate gland?Ans. Seminal vesicles are a pair of thin-walled muscular and elongated sacs which secrete a fluid for nourishment of sperms. Prostate glands also produce a fluid which is released in the urethra along with secretion of seminal vesicle. It affects the vaginal pH so that sperms move smoothly inside the vagina.
Q10. What are the changes seen in girls at the time of puberty?Ans. At the time of puberty, breast size begins to increase, with darkening of the skin of the nipples. Also, girls begin to menstruate at around this time.
Q11. How does the embryo get nourishment from its mother�s body?Ans. The embryo grows inside the mother�s womb and gets nourishment from its mother�s blood through placenta. Placenta contains villi which connects the embryo with the mother�s blood. These villi provides a large surface area for glucose and oxygen to pass from mother to the embryo.
Q12. If a woman is using copper-T, will it help in protecting her front sexually Transmitted diseases?Ans. No, it will not protect the woman from sexually transmitted diseases as fluid to fluid contact occurs in the vagina.