CBSE Solutions for Class 10 Biology

Select CBSE Solutions for class 10 Subject & Chapters Wise :

What is ‘reproduction’? Mention the importance of DNA copying inreproduction.

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Answer :

Reproduction is the process of producing new individuals of the same species
by existing organisms of a species, i.e. parents. The importance of DNA copying in reproduction are as follows:
(i) DNA copying is called DNA replication. In this process, one copy each of replicated DNA will be passed to daughter cells.
(ii) Variations may be introduced during DNA copying. This inbuilt tendency for variation during reproduction forms the basis of evolution.

What is the effect of DNA copying which is not perfectly accurate on the reproduction process?

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Answer :

 DNA copying is not perfectly accurate and the resultant errors are a source of variations in populations of organisms.

Define the terms unisexual and bisexual giving one example of each.

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Answer :

 Unisexual is the plant whose flowers contain either stamens or carpels but not both. Example: Papaya, Watermelon.
Bisexual is the plant whose flowers contain both stamens and carpels. Example: Hibiscus, Mustard.\

During fertilisation in plants, the following events take place:
(i) One of the male gamete fuses with the female gamete present in the embryo sac.
(ii) The other male gamete fuses with the two polar nuclei in the embryo sac.
The first fusion product gives rise to the zygote while the second one forms the endosperm.
The process of two fusions occurring in the embryo sac is called double fertilisation.

Gonorrhoea and syphilis are …………… infections while infections such as warts are …………… infections.

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bacterial, viral

A contraceptive device called the loop or …………… is placed in the uterus to prevent pregnancy.

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copper-T

The …………… convert into seeds and ovary converts into …………… after fertilisation in a flowering plant.

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ovules, fruit

To prevent the egg from reaching the uterus, the …………… is blocked in human female.

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fallopian tube

Sex ratio is declining at an alarming rate in some sections of our society due to …………… foeticide.

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female

To nourish the …………… lining of uterus thickens and gets richly supplied with blood.

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Embryo

A special tissue which provides nutrition to the embryo in the uterus is called ……………

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placenta

The transfer of pollen from one flower to the stigma of another flower is called as ……………

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cross pollination

The spores in Rhizopus are covered by …………… to protect them.

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thick walls

Inbuilt tendency for …………… during reproduction is the basis for evolution.

 
 
 
 
 
 
 
 
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variation

………….. is the term used to refer to the commencement of menstruation at puberty.

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Menarch

………….. is the virus that causes AIDS.

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HIV-Human Immuno Virus

The process of reproduction involving only one cell or one parent is called ………….. .

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Uniparental/ Asexual reproduction
 

………….. is called the production of new plants from stems, roots or leaves.

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Vegetative propagation

………….. is the ability of an organism to replace its lost body parts.

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Regeneration

Process of fertilization takes place in the ………….. tube in humans.

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fallopian

………….. is a duct coming from the urinary bladder which carries sperms.

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Answer :

Vas deferens
 

(a) List any four reasons for adopting contraceptive methods.
(b) If a woman is using Copper-T, will it help in protecting her from sexually transmitted diseases? Why? 

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Answer :

(a) Four reasons for adopting contra¬ceptive methods are:
(i) To increase the gap between, two children.
(ii)To prevent unwanted preg¬nancy.
(iii)To prevent transmission of STDs.
(iv)To control population growth. (b) If a woman is using a copper-T,
it will not help in protecting her from sexually transmitted diseases. Copper-T prevents only implantation in the uterus.

What does HIV stand for? Is AIDS an infectious disease? List any four modes of spreading AIDS.

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Answer :

HIV stands for Human Immunodeficiency Virus.
Yes, AIDS is an infectious disease.
Four modes of spreading AIDS are as follows:
(i) By having sexual contact with an infected person.
(ii) By the transfusion of blood from an infected person.
(iii) Through infected needles used for injection.
(iv) Through the placenta from the mother to child during pregnancy.

(a) Explain the role of placenta in the
development of human embryo.
(b) Give example of two bacterial and two viral sexually transmitted diseases. Name the most effective contraceptive which prevents spread of such diseases.

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Answer :

(a) Role of placenta in the development of human embryo: A special tissue develops between the uterine wall and the embryo (foetus) called placenta, where exchange of nutrients, glucose and oxygen takes place. The developing embryo will also generate waste substances which can be removed by transferring them into the mother’s blood through the placenta. The development of the child inside the mother’s blood takes approximately nine months.
(b) Sexually transmitted diseases (STDs) transmitted by bacteria are:
(i) Gonorrhoea (ii) Syphilis
STDs transmitted by virus:
(i) AIDS (ii) Genital warts
The most effective contraceptive which prevents the spread of these diseases is by the use of mechanical barriers such as physical devices like condoms.

Draw a longitudinal section of a flower and label the following parts:
(i) Part that produces pollen grain.
(ii)Part that transfers male gametes to the female gametes.
(iii) Part that is sticky to trap the pollen grain.
(iv) Part that develops into a fruit.

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List any three differences between pollination and fertilisation.

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Explain vegetative propagation with the help of two examples. List two advantages of vegetative propagation.

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Answer :

In vegetative propagation, new plants are obtained from the parts of old plants like stems, roots and leaves, without the help of any reproductive organ.
There are two ways of vegetative propagation:
(a) Natural Vegetative Propagation, and
(b) Artificial Vegetative Propagation.
Natural vegetative propagation by leaves: The fleshy leaves of Bryophyllum bear adventitious buds in the notches along the leaf margin.
Grafting: In this method of reproduction, two plants of closely related varieties are joined together so that they live as one plant.

  • The portion of a plant that is grafted on the other plant is called scion, and the plant in which grafting is performed is called the stock.
  • This method is applied to improve variety of fruits like mango, apple, peas, citrus and guava.
    advantages of vegetative propagation are:

(i) Vegetative propagation is a cheaper, easier and more rapid method of propagation in plants than growing plants from their seeds.
(ii) Better quality of the plants can be maintained by this method.

Write the full form of DNA. Name the part of the cell where it is located. Explain its role in the process of reproduction of the cell.

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Answer :

The full form of DNA is deoxyribonucleic acid. It is the genetic material found in the chromosomes, which are present in the nucleus of a cell.
Role of DNA in the process of repro¬duction of the cell:

 
DNA plays an important role in the reproduction of a cell. The reproducing cell produces an identical copy of DNA through some cellular mechanism. Since the newly formed copy of DNA lacks an organised cellular structure, the cell gets divided to provide cell cover to the newly formed DNA. Thus, two daughter cells are formed from the single cell as a result of the copying of DNA.

List any four reasons for vegetative propagation being practised in the growth of some type of plants.

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Answer :

(i) Vegetative propagation is a cheaper, easier and more rapid method of propagation in plants than growing plants from their seeds.
(ii) Better quality of plants can be maintained by this method.
(iii) It results in propagation of those plants which do not produce viable seeds or produce seeds with prolonged period of dormancy.
(iv) The plants generated from vegetative means are more uniform and genetically similar to the parent stock.

What is regeneration? State a reason why a more complex organism cannot give rise to new individuals through this method.

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Answer :

Regeneration is the ability of a fully differentiated organism to give rise to new individual organisms from its body parts. More complex organisms cannot give rise to new individuals through regeneration because:
(i) their body is highly complicated.
(ii) there are specific organs to do specific functions.
(iii) there is a labour division in the body of complex organisms.
(iv) regeneration is carried out by specialised cells which are not present in complex organisms.

(i) What is fertilisation? Distinguish between external fertilisation and internal
fertilisation.
(ii) What is the site of fertilisation in human beings?

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Answer :

(i) Fertilisation is defined as the fusion of a male gamete (sperm) with a female gamete (an ovum or egg) to form a zygote during sexual reproduction.

(ii) The site of fertilisation in human beings is in the fallopian tube of female reproductive system.

Column I

Column II

(i) Placenta

(A) Binary fission

(ii) Male gametes of plant

(B) Bryophylium

(iii) Budding

(C) Nourishment of embryo

(iv) Amoeba

(D) Yeast

(v) Vegetative propagation by leaves

(E) Pollen grains

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Answer :

(i) (C)
(ii) (E)
(iii) (D)
(iv) (A)
(v) (B)

Match the following columns

Column I

Column II

(i) Sexual maturity

(a) Placenta

(ii) Syphilis

(b) Hormonal balance

(iii) Callus

(c) Urethra

(iv) Oral pills

(d) Cervix

(v) Male hormone

(e) Puberty

(vi) Vas deferens

(f) Bacteria

(vii) Common passage for sperms and urine

(g) Tissue culture

(viii) Opening of uterus into vagina

(h) Testosterone

(ix) Gaseous exchange

(i) Vasectomy

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Answer :

Column I

Column II

(i) Sexual maturity

(e) Puberty

(ii) Syphilis

(f) Bacteria

(iii) Callus

(g) Tissue culture

(iv) Oral pills

(b) Hormonal balance

(v) Male hormone

(h) Testosterone

(vi) Vas deferens

(i) Vasectomy

(vii) Common passage for sperms and urine

(c) Urethra

(viii) Opening of uterus into vagina

(d) Cervix

(ix) Gaseous exchange

(a) Placenta

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The CBSE Books for class 10 are designed as per the syllabus followed Gujarat Secondary and Higher Secondary Education Board provides key detailed, and a through solutions to all the questions relating to the GSEB textbooks.

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