CBSE Class 10 Science How do Organisms Reproduce Assignment Set B

MCQ Questions for Class 10 Science Reproduction :-

 

Question. Fill in the following blanks with suitable words :
(a) The process of..............ensures continuity of life on earth.
(b) Plasmodium reproduces by the process of ............... fission whereas Paramecium reproduces by the process of .............. fission.
(c) Rose plants and sugar cane crop are usually grown by the ................. method.
(d) Vegetative reproduction of potato plants is done by using .................
(e) Strawberry plants are propagated by the natural........................ method.
Answer : (a) reproduction (b) multiple ; binary (c) cuttings (d) tubers (e) layering

 

 

Question. Which life process ensures that a plant or animal species will not disappear from this earth ?
Answer : Reproduction

Question. What is the name of the reproductive process :
(a) which involves two parents ?
(b) which involves only one parent ?
Answer : (a) Sexual reproduction (b) Asexual reproduction

Question. State whether the following statement is true or false : Spores produced by the bread mould plant are actually its seeds.
Answer : False

Question. Name the asexual method of reproduction in yeast.
Answer : Budding

Question. Name the asexual method of reproduction in (a) Hydra, and (b) Plasmodium.
Answer : (a) Budding: Budding is the asexual method of reproduction in Hydra.They reproduce by budding, when a small bud arises from the parent and seperates to form a new daughter Hydra. It is a type of mitotic division.
(b) Multiple fission : Plasmodium divides by multiple fission, which is a kind of asexual reproduction. The nucleus of the organism divides into multiple nuclei and each daughter nuclei share some cytoplasm of the parent cell and divides into many plasmodium parasites. This type of multiple fission is called schizogony.

Question. What is the name of asexual reproduction method in :
(i) Spirogyra, and (ii) Leishmania ?
Answer : (i) Spirogyra reproduces by fragmentation.
(ii) Leishmania reproduces by binary fission.

Question. Name the artificial propagation mehod used for the propagation of (a) rose plants, and (b) apple trees.
Answer : (a) Rose plants are artificially propagated through the method of cutting.
(b) Apple tree is artificially propagated through the method of grafting.

Question. Most of the plants reproduce by sexual method. Name two plants which can reproduce asexually.
Answer : Ferns and Mosses

Question. Which type of reproduction :
(a) involves gametes ?
(b) does not involve gametes ?
Answer : (a) Sexual reproduction (b) Asexual reproduction

Question. Name any two plants which are propagated by cuttings method.
Answer : Rose and grapes plants are propagated by the cutting method.

Question. Write down the different methods of asexual reproduction.
Answer : The different methods of asexual reproduction are:
Fission
Budding
Spore formation
Regeneration
Fragmentation, and
Vegetative reproduction

Question. Why are budding, fragmentation and regeneration, all considered to be asexual type of reproduction ?
Answer : Because in all these methods of reproduction, new organisms (offsprings) are obtained from a single parent without the use of sex cells or gametes.

Question. State whether human beings reproduce by sexual method or asexual method.
Answer : Sexual method

Question. (a) Name two animals which reproduce sexually.
(b) Name two animals which reproduce asexually.
Answer : (a) Dogs and Cows
(b) Amoeba and Hydra

Question. Name one organism which reproduces by spore formation.’
Answer : Bread mould (Rhizopus fungus)

Question. Name the method by which Paramecium reproduces. Is this method sexual or asexual ?
Answer : Binary fission ; Asexual method

Question. Name two plants :
(a) which can be grown from their broken stems.
(b) which can be grown from their leaves.
Answer : (a) Bryophyllum and Money plant (b) Bryophyllum and Begonia

Question. Which artificial propagation method is used for the production of jasmine plants ?
Answer : layering

Question. Name the natural method by which strawberry plants are propagated.
Answer : Strawberry plants are propagated by layering.

Question. Name two plants which are propagated by layering method.
Answer : Jasmine and strawberry

Question : Name the tubules where the sperms are produced. 
Answer : The seminiferous tubules are the site of the germination, maturation, and transportation of the sperm cells within the male testes.

Question : What is implantation? 
Answer : implantation is the attachment of the embryo to inner lining of the uterus. 

Question : Name the correct substrates for the following enzymes.
(a)Trypsin
(b)Amylase
(c)Pepsin
(d)Lipase
Answer : (a) Trypsin-Protein
(b) Amylase-Starch
(c) Pepsin-Protein
(d) Lipase-Fats

Question. How do bryophyllum reproduce?
Answer: Bryophyllum reproduce by budding in leaves

Question. What is implantation?
Answer: Placing of embryo in the uterine wall is called implantation

Question. Why do organisms reproduce?
Answer: Organisms reproduce to create more individuals like themselves.

Question. What are the various parts of human male reproductive system?
Answer: A pair of testis, a pair of vas deferens, prostrate glands, seminal vesicles, penis

Question. What is the basis for evolution?
Answer: The inbuilt tendency for variation during reproduction forms the basis of evolution.

Question. Which part of a cell contains information for inheritance of features in the form of DNA molecules?
Answer: Chromosomes

Question. Name the type of reproduction in which
i. Single parent is involved
ii. Two parents involved
Answer: i. Asexual reproduction
ii. sexual reproduction

Question. The rates of __________ and ________in a given population determine its size.
Answer: Birth and death

Question. Name the non-reproductive part of rhizopus.
Answer: Hyphae

Question. What is gestation period?
Answer: The development of embryo inside the uterus for approximately nine month period is called gestation period

 

Short Answer Questions

Question : What are the functions performed by testis in human beings?
Answer: The function of testis is to produce sperms and male sex hormone called testosterone.

Question : What could be the reasons for adopting contraceptive methods?
Answer: The reasons for adopting contraceptive methods could be:
1. Protection from sexually transmitted diseases such as HIV-AIDS, gonorrhoea, syphilis, warts etc.
2. Restricting the number of children.
3. Sufficient gap between successive births.
4. Enjoying a good reproductive health.
5. Controlling population.

Question : Why does menstruation occur?
Answer: Menstruation occurs in females when the egg produced inside the cervix is not fertilized. Since the egg does not fuse with the male gamete, so the thick and soft lining of uterus having a lot of blood capillaries in it are not required. This unfertilized egg dies within a day and the lining breaks down shedding blood along with other tissues. This comes out of the vagina in the form of bleeding.

Question : Why is vegetative propagation practised for growing some types of plants?
Answer: The process by which some plants can reproduce asexually by their vegetative parts like roots, stems and leaves is called vegetative propagation. It has many advantages.
Plants raised by this method can bear flowers and fruits earlier than those produced from seeds. Plants that have lost capability to produce seeds like banana, orange, rose and jasmine can be propagated. All plants produced are genetically similar to the parent plant.

Question : What are the different methods of contraception?
Answer: Contraception is the method to avoid pregnancy. Various methods of contraception are as follows:
Physical Barrier Methods: Use of condoms, diaphragms, cervical caps can be used.
These prevent the entry of sperms into the female genital tract by acting as a barrier between them.
Chemical Methods: Oral pills can be used which change the hormonal balance and stop release of egg. Vaginal pills kill the sperms.
Surgical Methods: This includes vasectomy (sperm duct is removed) in males and tubectomy (removal of small portion of fallopian tube) in females.

Question : What are the advantages of sexual reproduction over asexual reproduction?
Answer: In asexual reproduction, the offspring is almost identical to the parent because they have the same gene as their parent. Thus, variation is not present.
Sexual reproduction involves fusion of male and female gametes. The offspring exhibits diversity of characters because they receive some genes from the mother and some from the father. The mixing of genes in different combinations; results in genetic variations. This variation leads to the continuous evolution of various species to produce various organisms.

Question : How are modes of reproduction different in unicellular and multicellular organisms?
Answer: Unicellular organisms have only one cell. There is no separate tissue for reproduction.
So, they can reproduce by the process of fission or budding. Multicellular organisms contain various cells and have separate system for reproduction. So, they can reproduce by both sexual and asexual methods.

Question : How does binary fission differ from multiple fission?
Answer: Binary 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 divides repeatedly to form a number of equal sized and similar individuals, e.g., Plasmodium.

Question : (a) Write the function of following parts in human female reproduction system:
(i) Ovary (ii) Oviduct (iii) Uterus
(b) Describe in brief the structure and function of placenta.
Answer: (a) (i) Ovary: Release egg and female hormone estrogen
(ii) Oviduct: Transportation of ovum from ovary to uterus and it is a site of fertilization.
(iii) Uterus: Development of embryo
(b) Placenta: It is a disc embedded in uterine wall which contains villi on the embryo side of the tissue and blood space on mother side.
Function of placenta:
(i) Provides nourishment to embryo from mother’s blood.
(ii) Removal of waste embryo to mother’s blood. 

Question : Define vegetative propagation. List its methods and advantages.
Answer : In vegetative propagation new plants are obtained from the parts of old plants-stem, leaves or root without the help of any reproductive organ.

Natural methods of vegetative propagation

Artificial Method of Vegetative Propagation
1. Cutting
2. Layering
3. Grafting

Advantages of vegetative propagation
(i)The new plant produced by artificial vegetative propagation will be exactly like parent plant.
(ii)The fruit trees grown from cutting or grafting start to bear fruits much earlier.
(iii)Many plants can be grown from just one parent plant.
(iv)We can also get seedless plant by artificial propagation.

 

 

Question :  What are the different methods of contraception?
Answer :  Different methods of contraception are –
a) Barrier method – In this method, a device used to prevent the entry of sperms in the female genital tract example – Condom, Diaphragm, Cervical caps.
b) Chemical method – In this method certain drugs (containing hormones) are used by the females. These drugs are avaiblabe in the form of pills. There are two kinds of pills commonly used for preventing pregnancies – oral pills and vaginal pills or creams.
c) Intrauterine contraceptive devices (IUCD’S) – IUCD like copper – T is placed in the uterus – IUCD prevent implantation of the fertilized ovum inside the uterus.

Question :  What are the essential requisites for sexual reproduction?
Answer :  Essential requisites for sexual reproduction are –
a) Transfer of germ cells – Specialized germ – cells have to fuse together, which can happen by either of the following modes –
(i) External release of germ cells – In flowering plant
(ii) Internal transfer of germ cells – In animal cells.
Requirement of special organs –
For example –
a) An erectile organ called penis
b) Organs which can carry the baby for long period  

Question :  What is AIDS? Name its causal organism. Mention its symptoms.
Answer :  AIDS is a sexually transmitted disease. Its full form is acquired immune deficiency syndrome. It is a viral disease, caused by human immune deficiency virus. Its symptoms area) Destroys the immune system of body.
b) Persistent cough and fever.
c) Body attacked by other diseases like pneumonia, TB and certain cancers.

Question :  Describe any 3 methods of asexual reproduction
Answer :  Methods of asexual reproduction –
a) Primary fission – It is a type reproduction in which one parent organism divides into two new organisms. Firstly nucleus divide and then division of cytoplasm takes place.
b) Spore formation – A spore is a small microscopic structure with a thick wall. Spores are formed in a structure called sporangium. Nucleus inside sporangium divides repeatedly and produces many nuclei. Each nucleus is surrounded by cytoplasm and called spore.
c) Fragmentation – It is the breaking of an organism into two or more parts upon maturation, each of which grows to form a new individual.

 

Long Answer Questions

Question :  Describe triples fusion in plants? Where does it occur? Draw a neat and clean well labeled diagram to support your answer.
Answer :  After pollination, the pollen grains germinate n the stigma by producting pollen tube. This pollen tube is formed from inner wall of the pollen grain. It penetrates the stigma and passes through the style and enters the ovule through an opening called male gamete it releases two male gametes in the embryo sac. One male gamete fuses with egg cells and second fuses with two polar nuclei. The fusion of one male gamete with the egg cells is called syngamy. The fusion
of second male gamete with two polar nuclei is called triple fusion. This process occurs in ovary.

Question :  Draw a well labeled diagram of female reproductive system and mention its part 
Answer : 

a) A pair of ovaries – ovaries produces ova and female sex hormone. One egg is produced every month by one of the ovaries. Ova are picked up by the funnel shaped fallopian tubes.
b) Fallopian tubes – There are two fallopian tubes. It carries ova from ovary to the uterus. Fertilization occurs in fallopian tubes.
c) Uterus – Pear shaped hollow muscular organ. Fertilized ovum remains attached to the uterus wall.
d) Vagina – It is a narrow muscular tube. Its upper end is connected to the cervix of the uterus and lower end opens outside through an opening. It is a place for copulation.