The chapter How do organisms reproduces explains the different methods of
reproduction in different organisms. These solutions have been prepared by
experienced teachers.
.png "RBSE Solutions for Class10 Science Chapter 7 How Do Organisms Reproduce?")
If you are preparing for RBSE class 10 board exams, then these solutions of intext and end exercise questions will help you a lot.
These solutions cover a complete syllabus and will let you solve homework and
assignments in an easy way.
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Board |
RBSE |
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Subject |
Science |
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Chapter |
How Do Organisms Reproduce? |
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No. of Intext questions |
12 |
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No. of End exercise questions |
11 |
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Prescribed Book |
NCERT Science |
How Do Organisms Reproduce?
Answers of Questions on Page 114
Q.1 What is the importance of DNA copying in reproduction?
Answer
Environment is not stable; it changes continuously so the particular species will not be able to survive in changed environment. Reproduction is a process in which an organism produce young one similar to itself. In this process characters are transmitted by DNA copying.
DNA copying has following importance in reproduction
i.
1)Maintains the characteristics of species.
ii.
2)Maintains the continuous survival of life
iii. 3)The characteristics of organisms are transmitted to their progeny.
iv. 4)It produces variations in organisms which is the basis of evolution of new species.
Q.2 Why is variation beneficial to the species but not necessarily for the individual?
Answer
The variations are beneficial to a species and enable them to survive in a changed environment. A favorable variation in a species makes them survive in a changed
environment. In a changed environment individual organism would die but their offsprings with variations survive in a changed environment. So we can say that
variations are beneficial to a species but not for the individual.
Answers of Questions on Page 119
Q.1 How does binary fission differ from multiple fission?
Answer
Binary fission: – In this method; nucleus divides into two parts and by division of cytoplasm, two daughter organisms are formed.
Multiple fission: – In this method; nucleus divides in several parts and each nuclear part getting some cytoplasm forms a daughter organism.
.webp "Multiple fission in plasmodium")
Q.2 How will an organism be benefited if it reproduces through spores?
Answe
An organism is benefited if it reproduces through spores, in the following ways:
(i) Spores are formed in a large number.
(ii) Spores have an outer thick wall that protects them in adverse conditions, when
conditions become favorable (Proper moisture) , they can to grow.
Q.3Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Answer
More complex organisms cannot give rise to new individuals through regeneration because they have specialized cells, tissues, organs and organ systems to perform different functions. So multicellular organisms have high body organization. That’s why they cannot reproduce though regeneration.
Q.4 Why is vegetative propagation practiced for growing some type of plants?
Answer
Vegetative propagation practiced for growing some type of plants because of following reasons-
(i) Some plants such as banana, orange and rose do not produce seeds so the vegetative propagation is practiced to grow them.
(ii) Vegetative propagation is a fast method for developing new plants earlier.
(iii) Plants raised by vegetative propagation bear flower and fruits earlier than those
produced from seeds.
(iv) Seedless fruits are produced by the process vegetative propagation.
(v) Desired characters can be maintained in variety of species by this method.
Q.5 Why is DNA copying an essential part of the process of reproduction?
Answer
DNA copying is an essential part of the process of reproduction because so that the characteristics of the parent organisms are transmitted to its offspring and in
this process some variations are also produced in the offspring.
These variations lead to some changes in offsprings that provide an organism the capability to survive in changing conditions.
Answers of Questions on Page 126
Q.1 How is the process of pollination different from fertilisation?
Answer
Pollination: – In this process pollen grains (male gametes) are transferred from the anther of a flower to the stigma of same or other flower.
Fertilization:- In this method ; pollen grains (male gametes) fuses with female gamete (egg cell) to form zygote.
Q.2 What is the role of the seminal vesicles and the prostate gland?
Answer
Seminal vesicle and prostate gland secrete fluids which forms a part of the
semen. The fluid secreted from seminal vesicle forms 60% of semen. It makes the transport of sperms smooth. This fluid protects the sperms from the
acids present in the urethra and provides nutrition to sperms in the form of
fructose, calcium and some enzymes.
Q.3 What are the changes seen in girls at the time of puberty?
Answer
The various changes occur in girls at puberty are:
1. Breast size increases and mammary gland develop.
2. Hair grows under armpits and pubic region.
3. The hips broaden.
4. Deposition of fat in various parts of body like hips and thighs.
5. Fallopian tube, uterus and vagina enlarge.
6. Ovaries start to release eggs.
7. Menstruation cycle starts.
Q.4 How does the embryo get nourishment inside the mother’s baby?
Answer
In mother’s body, the embryo gets nutrition from the mother’s blood with the help of placenta. Placenta is formed by foetal and maternal tissue. Placenta contains villi. There are empty spaces in mother’s tissues that cover the villi. Villi provide a large surface area for the transfer of glucose, oxygen and other substances from the mother to the embryo.
Q.5 If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?
Answer
No , If a woman is using a copper-T, it will not help in protecting her from sexually transmitted diseases.
Answers of End Exercise Questions on Page
Q.1 Asexual reproduction takes place through budding in
(a)amoeba
(b)yeast
(c)plasmodium
(d)leishmania
Answer (b) yeast
Q.2 Which of the following is not a part of the female reproductive system in human beings?
(a)Ovary
(b)Uterus
(c)Vas deferens
(d)fallopian tube
Answer (c) vas deferens
Q.3 The anther contains
(a)sepals
(b)ovules
(c)carpel
(d)pollen grains
Answer (d) pollen grains
Q.4What are the advantages of sexual reproduction over asexual reproduction?
Ans.
(i) In sexual reproduction the offspring are similar to their parents, but not identical to them or to one another. This is because the offspring receive
genes from two different parents. So these genes mix in various different combinations. Due to this all of the offspring have genetic variations.
So in sexual reproduction, due to different variations offsprings have adaptations to their surroundings and they can survive.
(ii).In asexual reproduction- the offspring are almost identical to their parent because they have the same genes as their parent. So, much genetic variation is not possible in asexual reproduction. So in asexual reproduction due to less genetic variations, this inhibits the evolution of the organism.
Q.5What are the functions performed by the testes in human beings?
Answer
Functions of testes are as follows
(i)Sperms are formed in testes.
(ii)They secret the hormone testosterone which regulates the formation of sperms and
brings changes in appearance of boys at the time of puberty.
Q.6Why does menstruation occur?
Answer
At puberty in girls or female, ovaries release eggs(ovum) regularly and at the same time lining of uterus starts thickening to receive fertilized egg but if the egg(ovum) does not get fertilized due unavailability of sperm then the thick and soft inner
lining of uterus is no longer needed and hence it breaks. So, the thick and soft inner lining of uterus along with the blood vessels and the dead eggs comes out of the vagina in the form of blood called menstruation. Menstruation occurs after the interval of every 28 days.
Q.7Draw a labeled diagram of the longitudinal section of a flower.
Answer
.webp "labeled diagram of the longitudinal section of a flower.")
Q.8What are the different methods of contraception?
Answer
Following are the different methods of contraception-
(i) Chemical method: In this method a woman uses oral pills which are hormonal preparations and suppress the release of ovum in fallopian tube. These are called oral contraceptives.
On the other hand vaginal pills/ creams are spermicidal. The chemicals in these kill the sperms during their journey in the vaginal tract.
(ii) Barrier method: condom, diaphragm and cervical caps are used in this method which prevents the entry of sperms in the female genital tract during sexual intercourse.
(iii) Intrauterine contraceptive devices: Intrauterine contraceptive devices such as copper-T are placed safely in the uterus at hospitals. It prevents the sperms to reach the uterus.
(iv) Surgical method : In this method, a small part of vas deferens of male and fallopian tube of female is cut or tied by surgery. It is called vasectomy in males and tubectomy in females.
Q.9How are the modes for reproduction different in unicellular and multicellular organisms?
Answer
In unicellular organisms reproduction takes place by binary fusion or multiple fission (asexual reproduction) while in multicellular organisms reproduction takes place
by budding (hydra), vegetative propagation asexual methods and fusion of male and female gametes (sexual reproduction).
Q.10How does reproduction help in providing stability to population of species?
Answer
Population of a particular species decreases due to death or other reasons but reproduction add new individuals to the species. Reproduction also helps to generate copies of individuals which are suited to a particular environment.
Q.11What could be the reasons for adopting contraceptive methods?
Answer
Contraceptives are adopted due to the following reasons
(i) For prevention of unwanted pregnancy.
(ii) To control the birth rate and prevent the increase in population
(iii) These methods prevent sexually transmitted disease.
RBSE Class 10 Science Questions Answers
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