Various contraceptive devices are being used by human beings to control the size of population. Differences between asexual and sexual forms of reproduction are follows : Hydra is simple multicellular animal. To provide safety from sexually transmitted diseases. But it is important for the existence and continuity of the species. Mechanical barriers prevents unwanted pregnancy. Name any two areas related to reproductive health which have improved over the past 50 years in our country. Suggest one preventive method which could be observed. Ans: They are asked to refrain from sex because they are not mature enough to bear the responsibility of child. It is through the placenta that all the requirements of the developing fetus like nutrition, respiration and excretion, etc., are met from the mothers body. The parts of a flower which serve the same function as following do in the animals are Embryo has two parts: plumule and radicle. One of the most common reason for deterioralion of womens health is frequent conception and child bearing. (d) upper surface of stigma and lower part of style. Answer: If you have any query regarding NCERT Class 10 Science Notes Chapter 8 How do Organisms Reproduce, drop a comment below and we will get back to you at the earliest. In the context of reproduction of species state the main difference between fission and fragmentation. 23. Refer to answer 81. This discharge is known as menstruation which lasts for about 2-8 days. It has male reproductive part cal led stamen and a female reproductive part called carpel. This is an asexual mode of reproduction. It is an ability of simple organisms to re-grow their lost body parts. 24. Ans: When the egg is not fertilized and the uterus has not received a fertilized egg, the lining becomes thick. Draw a labelled diagram of a human female reproductive system. The embedding of embryo in the thick lining of the uterus is called implantation. Fragmentation is the process found in multicellular organisms. Heterothallic mycelia require two different, but compatible, mycelia to reproduce sexually. During the growth of Rhizopus, small rounded, bulb-like structures develop at the top of the erect hyphae. The list of indigenous United States animals is long and includes well known creatures like coyotes and raccoons, and lesser known animals like the glass lizard and adorable pika.The incredible 2,972 estimated animals native How does the use of these techniques have a direct impact on the health and prosperity of a family? The ovaries grow rapidly and ripen to form a fruit. Answer: (a) The ovary splits open Pollen grains are the male gametes which fertilise the egg cell present in the ovule of a flower. Write names of one male and one female sex hormone. Answer: with Potential Applications in Industrial Biotechnology", "The establishment of a marine focused biorefinery for bioethanol production using seawater and a novel marine yeast strain", "Comparative analysis of cytokinesis in budding yeast, fission yeast and animal cells", "Severing all ties between mother and daughter: cell separation in budding yeast", 10.1002/(SICI)1097-0061(199812)14:16<1529::AID-YEA357>3.0.CO;2-0, "Microbial and bioconversion production of D-xylitol and its detection and application", International Journal of Biological Sciences, "Yeast: an experimental organism for 21st Century biology", "Differentiation of industrial wine yeast strains using microsatellite markers", "Microarray karyotyping of commercial wine yeast strains reveals shared, as well as unique, genomic signatures", "Research enables yeast supplier to expands options", International Journal of Food Microbiology, "Eureka! Which of the following is not a part of the female reproductive system in human beings? The two fusing gametes posses characters of their parents in their DNA. Sexual reproduction involves two parents with different sets of characters. Female Reproductive System: It consists of the following components. The female gonads in human beings are pair of ovaries located in the abdominal cavity near the kidneys. Ans: Copper-T is used to prevent pregnancy. (i) Bacterial infections (b) a mature Spirogyra filament attains considerable length [3][47] Exposure of S. pombe to hydrogen peroxide, an agent that causes oxidative stress leading to oxidative DNA damage, strongly induces mating and the formation of meiotic spores. These two fallopian tubes unite into an elastic bag like structure known as the uterus. Off-springs produced from sexual reproduction cannot be clones hence statement iv) is wrong. Name the causative agent of the disease kala- azar and its mode of asexual reproduction. (c) on maturation sporangia burst? In the process of reproduction, if DNA copying is not perfectly accurate, variation occurs. The ovary grows rapidly and ripens to form a fruit. (i) Fusion of male and female gametes coming from two different and sexually distinct individuals, exhibit diversity of characters in offspring. The head is linked with testis and tail is linked with vas deferens. The ovule develops a tough coat around it and is gradually converted into a seed. (i) Implantation of zygote refers to the process of attachment of the blastocyst on the inner wall of the uterus, It occurs on 7th day after fertilisation and is controlled by estrogen and progesterone hormones. Answer: List four modes of asexual reproduction other than fission in the living organisms. (ii) If a sperm is not available at the time of ovulation, then fertilisation of ovum does not take place. (d) Neither flower A and nor flower B can show self-pollination. List any two modes of asexual reproduction in animals. Question 145. Would a Planaria cut vertically into two halves regenerate into two individuals? Question 37. Is this method sexual or asexual? Testosterone controls the development of reproductive organs and secondary sexual characters. Placenta performs the following functions: Question 95. it brings variations in next generation which is the basis for evolution. Question 17. Question 46. In this way, the parent Hydra produce a new Hydra. Seedless plants can be obtained by artificial vegetative propagation. Answer: Give two reasons for adopting contraceptive devices in humans. Most were members of the genus Candida; the most common species in honey stomachs was Dekkera intermedia and in flower nectaries, Candida blankii. Thus, chromosome number remains unchanged. Ans: The preventive method used by the wife could be the use of oral pills or loop or Copper-T. 30. The nucleus of the cell divides repeatedly producing many nuclei. Formulae Handbook for Class 10 Maths and Science. The reproductive unit is gamete, which is unicellular and haploid. Regeneration is the ability of organisms to give rise to new individual organisms from their body partrs. What is fertilisation? Name the type of reproduction they are involved in. buds produced in the notches along the leaf margin of Bryophyllum fall on the soil and develop into new plants. Hence more number of chromosomes means more number of DNA. There are two types of pills generally used for preventing pregnancies i.e oral pills and vaginal pills or creams. Chromosomes are made of DNA. This cycle takes place roughly every month and is known as menstruation. These in turn may allow few individuals of a population to survive in an altered niche and becomes the basis of evolution and over time. The rate of birth and death in a given population will determine the size of a population. It destroys the immune system of the body. (i) Bacterial infection causes gonorrhoea, syphilis. 9. It is known as vasectomy. Question 3. Ans: Reproductive organs of flower are sepals, petals, stamens and pistils. Advantages of contraception: Help in birth control, prevent sexually transmitted diseases, prevent unwanted pregnancies, keep population explosion in check. (ii) How does A reaches part B? In vasectomy small pieces of both the vas deferens are cut and removed. 23. (AI 2017) 5. Reproduction is one of the most important characteristics of living beings because : Question 6. The other marine yeasts were grouped as obligate or indigenous marine yeasts, which are confined to marine habitats. (2020) Why is fertilisation not possible without pollination? Question 42. Spores help organism to survive harsh environmental conditions as spores are covered by thick walls which protect them until they come in contact with moist surface and germinate. After a few days, roots emerge from this region and branch is cut off from the parent plant. The causative agent of Kala-azar is Leishmania and the mode of asexual reproduction is binary fission. Plants can bear flowers, fruits more quickly than those produced from seeds. Stamens are male reproductive parts and produce pollen grains that contain male gametes. It plays an important role in continuous evolution of better organisms that may lead to the origin of new species. Justify. The fetus is connected to placenta in mothers body through umbilical cord. The production of new organisms by the existing organisms of the same species is known as reproduction. (ii) Blobs developing at the tip of hyphae are called sporangia which contain spores. What is a clone? [102] At the time, it was the most complex organism to have its full genome sequenced, and the work seven years and the involvement of more than 100 laboratories to accomplish. Question 5. (ii) where fertilisation takes place Question 2. What is the function of pollen grains in flowers? (b) (i) A is pollen grain. Stamen is the male reproductive part and it produces pollen grains. It helps in maintaining lower temperature which favors the perm formation. What is the role of the seminal vesicles and the prostate gland ? [121] In oenology, the major spoilage yeast is Brettanomyces bruxellensis. Pollen tube grows through tissues of stigma, style & reaches ovary. Various ways to avoid pregnancy are given below. Petals, sepals, stamens, style and stigma shrivel and fall off. (b) fusion of nuclei of male and female gamete How are the modes of reproduction different in unicellular and multicellular organisms? These buds develop into tiny individuals and detach form parent body once they become fully mature. It contains villi that provides a large surface area to pass glucose and oxygen from mother to embryo. When conditions are favourable the cyst breaks and small offspring are liberated. (ii) Fallopian tube is the part where fertilisation takes place. (Delhi 2014) Write names of those parts of a flower which serve the same function as the following do in the animals Therefore, if a child inherits X chromosome from her father, will be a girl and the one that inherit Y chromosome will be a boy. [8] Researchers speculate a mixture of flour meal and water was left longer than usual on a warm day and the yeasts that occur in natural contaminants of the flour caused it to ferment before baking. Question 36. (ii) They are the sexual reproductive organs, (iii) They are produced in all groups of plants, (iv) After fertilisation, they give rise to fruits. The process of development of a seedling from the embryo under appropriate conditions is known as germination. Potato in the store room starts sprouting due to vegetative propagation. avoiding prostitution, multipartner sex and homosexuality. (i) Spore formation in Rhizopus: This is an asexual method of reproduction in bacteria and fungi. (Foreign 2016) S.cerevisiae has been sold commercially by the Dutch for bread-making since 1780; while, around 1800, the Germans started producing S.cerevisiae in the form of cream. [40] Marine yeast was successfully used to produce bioethanol using seawater-based media which will potentially reduce the water footprint of bioethanol.[43]. Answer: If the egg is not fertilized it remains for one day. In biyophyllum buds are produced in the notches along the leaf margins and when they fall on the soil, they develop into new plants. Question 16. (ii) Multiple fission in Plasmodium. Hormone testosterone brings about the development of secondary sexual characters during puberty in boys like growth of facial hair, deepening of voice, growth of scrotum and penis, accumulation of muscle mass, etc., and also regulates formation of sperms. Why is variation beneficial to the species but not necessarily for the individual? Ans: Difference between pollination and fertilization is as follows: The pollination process takes place when pollen grains are transferred from another to the stigma. Question 6: State whether human beings reproduce by sexual method or asexual method. It can be seen in Hydra and Planaria and is known as regeneration. 1. (2018) This part or fragment grows to form a new individual. Spores are usually produced in sporangia. Under which mode of reproduction is vegetative propagation placed and why? (i) In asexual reproduction, the offspring are almost identical to their parent because they have the same genes as their parent. The organisms which are able to survive, may reproduce to develop population which is adapted or suited to the varied conditions. These buds may get detached from the leaves, fall to ground and then grow to produce new Bryophyllum plants. What would be the ratio of chromosome number between an egg and its zygote? (c) HIV-AIDS How does reproduction help in providing stability to populations Of species? They prevent the entry Of sperms in the female genital tract during copulation. generation of diversity) are likely to be insufficient for generally maintaining sex from one generation to the next. Explain with the help of suitable example. Select two plants from the following which are grown by this process : Banana, Wheat, Mustard, Jasmine, Gram (Foreign 2016) The fluid secreted from seminal vesicle forms 60% of semen while the fluid secreted from the prostate gland forms 30% of the semen. Explain in brief. What is asexual reproduction? CBSE 10 Science How do Organisms Reproduce. (c) pollen grain in anther and upper surface of stigma. Sperm comes out from testis into the vas deferens and then passes through urethra before ejaculation. (a) Name the parts labelled as A, B, C and D in the diagram given below: (a) (i) Testes : The two testes in male are the sites where male gametes, i.e., sperms are formed. Question 43. (iii) Uterus Answer: Cryptococcus neoformans and Cryptococcus gattii are significant pathogens of immunocompromised people. Ans: Three methods of asexual reproduction are primary fission, spore formation and fragmentation. Answer: 52. Yeast killer toxins may also have medical applications in treating yeast infections (see "Pathogenic yeasts" section below). s m p r v a r n z /) is the sole living species of the genus Sequoia in the cypress family Cupressaceae (formerly treated in Taxodiaceae).Common names include coast redwood, coastal redwood, and California redwood. This leads to diversity in the population which helps in natural selection. Unisexual Flower: papaya, watermelon What is the difference between fission and budding? Question 1 Each ovule contains only one female gamete of the plant. 2. (ii) Seminal vesicle (a) The longitudinal section of a flower is as follows : Question 148. The different methods of contraception are as follow : (iv) Spirogyra Also give one example of each. Sexual reproduction results in the origin of. Its muscular wall helps in expelling of baby during childbirth. 55. Answer: (a) List two sexually transmitted diseases in each of the following cases: (ii) Air layering: This method is used in plants like crotons whose branches cannot be bent and buried in the soil. (c) Vas deferens is a part of male reproductive system in humans. In a germinating seed, which parts are known as future shoot and future root? Its full form is acquired immune deficiency syndrome. But in organisms like Leishmania, having whip like structure at one end of the cell, binary fission occurs in a definite orientation in relation to these structures. Spores are asexually reproducing bodies having a thick protective wall. The child is bom as a result of rhythmic contractions of the muscles in the uterus after nine months (36 weeks) of development inside the mothers womb, called Gestation Period. Plant propagation is the process of plant reproduction of a species or cultivar, and it can be sexual or asexual. Answer: (b) does not involve gametes ? The yeast has a negative effect on the bacteria that normally produce antibiotics to kill the parasite, so may affect the ants' health by allowing the parasite to spread. (AI 2014) I. asexual reproduction involves only one parent. The release of an ovum from the ovary into the abdominal cavity is known as ovulation. (i) Use of condoms: Condoms are thin rubber tubes worn over the penis before sexual intercourse. Question 4. (i) eggs develop (iii) female germ cell and (iv) ovule on it. Question 126. (d) pollen grains (i) Sexual reproduction takes place in multicellular organisms. Answer: DNA copying is the production of similar copies of DNA present in a cell using various chemical reactions. new species. Answer: (a) only similarities with parents (Foreign 2015) (b) State the meaning of pollination and mention a distinguishing feature between self-pollination and cross-pollination. Explain the process of regeneration in Planaria. But, all the three reproduce asexualiy. Vasectomy: It involves cutting and ligating the vas deferens in males. Hence reproduction linked to population if a species. Write about the events that occur till the seed formation in the ovary. Mint reproduces naturally by roots. AIDS is a sexually transmitted disease. Answer: This disc remains embedded within the uterine wall and has villi on the embryos side of the tissue. (i) (a) Testis anther Cytokinesis: Division of cytoplasm. 16. Question 131. The introduction of variations during reproduction provides stability to the populations of various species by preventing them from getting wiped out during adverse conditions. Reproduction in Human Beings Reproduction is the process of producing new organisms of the same kind. (a) they reproduce asexualiy 9. When the ovum is fertilized, it starts dividing in the form of a ball or cells or also known as embryo. Mention secondary sexual characters in human male and female. One of the male gametes reaches the ovary through pollen tube and fuses with egg to form zygote. Style is an elongated tubular structure which connects stigma with ovary. 32. Frequent and unwanted pregnancies can be avoided by adopting contraceptive methods. (i) Testes produce sperms and secrete a hormone called testosterone. Achieved by the growth of the pollen tube so that the male gamete reaches the female germ cells. Barrier method or mechanical method (Condom/Diaphragm): Prevents the meeting of sperems and ova. Write the functions of the following in human female reproductive system. Question 85. (AI 2017) Ans: Flow chart showing various types of reproduction with example is as follows: 17. It is observed in Plasmodium. Many other common examples of vegetatively propagating plants are onion, banana, garlic, ginger, turmeric, bryophyllum and water hyacinth. (c) How does the amount of DNA remain constant though each new generation is a combination of DNA copies of two individuals. Answer: Two types of pollination are: Ovaries: Paired ovaries are located in the abdominal cavity near the kidney. Medical termination of pregnancy (MTP) or abortions is carried out to eliminate the developing embryo. How are the modes for reproduction different in unicellular and multicellular organisms ? (Delhi 2011) Refer to answer 21. The process of pollination (in plants) ensures that male gametes bearing structure called pollen comes in contact with the female reproductive structure of the plant. Students are recommended to study this Exemplar for a thorough understanding of the concepts involved in reproduction in organisms. 20. Answer: Answer: Fertilization: Fertilization is the process of fusion of male and female gamete to form a zygote during sexual reproduction. A girl attains her puberty at the age of 11 years and a boy at 13 years but, still they are asked to refrain from sex, why? (a) Draw a diagram of the longitudinal section of a flower and label on it sepal, petal, ovary and stigma. which takes place in all sexually reproducing organisms. Therefore, amount of DNA remain constant. Here, haploid gametes fuse to form diploid zygote which develop into a mature organism. Differentiate between self-pollination and cross-pollination. Answer: 10. After the process of fertilisation, the ovary in the flower thickens and enlarges to form the fruit, whereas the ovule becomes the seed containing the embryo. Yeasts, like all fungi, may have asexual and sexual reproductive cycles. Protozoan reproduce by binary fission as well as by multiple fission. paving either stamens or carpels for example; Papaya, Watermelon. Pollination results in the deposition of related pollen grains over the receptive stigma of the carpel. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. Question 130. Also, check CBSE Class 10 Science Important Questions for other chapters: CBSE Class 10 Science Important Questions, 1. However, organisms like Leishmania. In this method, the parent organism splits to form many new organisms at the same time. Plants like rose, sugarcane, cactus, etc., can be rapidly propagated through stem cuttings as this method produces new plants from just one plant quickly without waiting for flowers and seeds. Answer: For more such important questions from this chapter, refer to Vedantu (vedantu.com). Question 5. Question 46. Cell division involves mitosis and meiosis both. 16. Answer: Question 20. Some contraceptive methods like condoms also prevent spread of STDs and dangerous diseases like HIV-AIDS. During World War II, Fleischmann's developed a granulated active dry yeast which did not require refrigeration, had a longer shelf life than fresh yeast, and rose twice as fast. It enables to combine the most desirable characteristics of two plants. (Foreign 2014) Since they possess exact copies of the DNA of their parent, clones exhibit remarkable similarity. The sperms travel upwards and reach the fallopian tube where one sperm fuses with the ovum to form the zygote. (d) Multiple fission Organisms divide into many daughter cells simultaneously, e.g. Question 13. 27. Only its pollen tube does so. Answer: For John Molson, who made his livelihood in Montreal prior to the development of the fridge, the brewing season lasted from September through to May. (AI 2015) (2020) Question 2. The male gonads in human beings are a pair of testes. Question 133. Pollination is important because it brings pollen grains to the female reproductive part (carpel) of the plant that leads to fertilisation. Only angiosperms produce flowers hence statement iii) is wrong. (2020) Question 81. Asexual reproduction generally occurs during favourable environmental conditions and when there is an abundance of food. The genetical similarity is maintained in the plants. Hence cell division is a type of reproduction in unicellular organisms. The two fallopian tubes unite to form an elastic bag like structure called uterus. The thick lining of the uterus, which was prepared by the body for receiving the egg, then sheds itself which comes out through the vagina in the form of blood and mucosal tissue. When the spores fall on a suitable medium, each one forms a new individual. Answer: This method is cheap and can be easily employed to reproduce plants, especially fruit plants. (AI 2011) It last for 3-5 days. Answer: In this process three nuclei, two polar nuclei and one male gamete is involved, so it is called triple fusion. Name the life process of an organism that helps in the growth of its population. 2. 3. (iv) Style (Foreign 2015) If fertilisation does not occur, the thick and spongy lining of the uterus slowly breaks and comes out through the vagina as blood and mucus. With the help of suitable diagrams, explain the various steps of budding in Hydra. (b) Female gamete/egg is not fertilised. 1 4 days The ovary starts preparing for the maturation of a new follicle. What is multiple fission? 31. The breast size begins to increase with darkening of the skin of the nipples at the tip of breasts. Beverages such as mead, wine, beer, or distilled spirits all use yeast at some stage of their production. (b) Ovary develops into a fruit and ovulesdnto seeds as in the above given diagram fertilisation has already taken place. Ans: If mature ovum is not fertilized in a female it gets released into fallopian tubes. (Delhi 2016) Formation of daughter organism takes place from a small projection called as bud. Question 5 The reproductive parts of an angiosperm are stamen (male reproductive part) and carpel/pistil (female reproductive part). Free PDF download of Important Questions with solutions for CBSE Class 10 Science Chapter 8 - How do Organisms Reproduce? (b) zygote, gametes, embryo, seedling What is DNA? Write the importance of this difference. (Foreign 2016) Asexual reproduction takes place through budding in [NCERT] Pelvis region becomes broad and buttocks become heavy due to deposition of fat. (a) (i)Threadlike non-reproductivestructures present in Rhizopus are called hyphae. Maintenance of personal hygiene among youngsters and proper knowledge of their reproductive parts helps them adjust with the physical changes and cope with emotional disturbances. Grafting is used in plants such as banana, orange, rose and jasmine because they lose the capacity to produce seeds. Advantages of vegetative propagation are as follows: Question 39. Regeneration : It is the ability to give rise to new organism. [7] Most yeasts reproduce asexually by mitosis, and many do so by the asymmetric division process known as budding. An organism is benefited by reproducing through the spores because spores are surrounded by a thick layer which protects them in adverse conditions. Refer to answer 120 (b) for figure. Fermentation can be done with this endogenous "wild yeast",[66] but this procedure gives unpredictable results, which depend upon the exact types of yeast species present. [42] Among these isolates, some marine yeasts originated from terrestrial habitats (grouped as facultative marine yeast), which were brought to and survived in marine environments. Following changes are observed in the uterus subsequent to implantation of the young embryo. (b) Refer to answer 120 (b). The various methods of vegetative propagation are: Layering: In layering, roots are induced on the stem of a rooted plant. This produces variation in offspring. One part is of in situ rooted plant called stock and another part from superior quality plant called scion. . Vegetative propagation is practiced for growing such plants which usually do not produce seeds or produce non-viable seeds. Moreover, waste substance of embryo are removed through placenta into the (iii) Amoeba The zygote divides and redivides as it descends into the uterus and the embryo gets implanted in the endometrium. Previous Year Questions & Important Questions of How Do Organisms Reproduce Class 10 Science Chapter 8 will help the students to score good marks in the board examination. Stigma is sticky so that pollen can stick to it. Our experts cautiously go through the entire chapter, sample papers, and previous years question papers to prepare the perfect set of important questions from each chapter. Pollination: The process of transfer of pollen grains from an anther to the stigma of the flower is pollination. Role of placenta: Question 56. Gametes carry variations generated during its formation (meiosis). (Foreign 2016) 21. What are the advantages of sexual reproduction over asexual reproduction? Name a multicellular organism which reproduces by this method. 22. Testes also produce the male sex hormone called testosterone. Question 1. Background. Discuss any one method with example. How do Plasmodium and Leishmania reproduce? 29. It helps to tide over unfavorable conditions. Examples are ferns like Nephrolepis, Marsilea, Pteris, Adiantum, Equisetum, Selaginella, Lycopodium, etc. Ans: The sex determination is a crime in India. 5. The pollen grains produce male gametes which fuse with (egg cel I) female gamete present in the ovule. To make this easier, the experts at BYJUS have created the NCERT Solutions with the aim of helping students score well in the Class 10 exams. (c) Refer to answer 130 (c). (Delhi 2012) Answer: Example, sugarcane, rose, grapes by layering or grafting. In budding, one or more outgrowths appear on one side, which enlarges in size. (iii) It always results in the formation of zygote. Draw diagrams to explain the regeneration that takes place in each of the body parts of Planaria when its body is cut into three pieces. Many plants can be grown from one plant by vegetative propagation. Wheat, Tomato, Rose, Pea, Gram, Corn, Banana (Foreign 2014) The following figure shows Hydra reproducing by the method of budding. (ii) Plasmodium reproduce by multiple fission in which the parent organism splits to form many new organisms at the same time. (d) the formation of gametes by a reproductive organ. In multiple fission, nucleus repeatedly divides to form a large number of nuclei, which reach at the periphery. Therefore, any desirable features of the parent plant will be replicated in the new plants. What is the number of chromosomes in the zygote? Part of stock plant) remain rooted but scion is separated from the mother plant. Explain giving one example of each, the unisexual and the bisexual flowers. What are the male and female gonads in human beings ? (b) yeast Name the hormone it secretes and write its functions. The process of formation of entire organism from the body parts of a fully differentiated organism is called regeneration. Explain how, offspring and parents of organisms reproducing sexually have the same number of chromosomes? (ii) Hydra Budding What is the product of fertilization? (a) Identify A, B, C and D in the given diagram and write their names. (c) Vas deferens (Foreign 2012) Answer: Question 18. Answer: (a) What is spore formation? What happens when a pollen lands on a suitable stigma ? Question 50. Secretion of female sex hormones (estrogen and progesterone). Skin becomes oily and pimples may appear on the face. Why is variation beneficial to the species but not necessarily for the individual? (i) Female germ cell In the age group of 10-14 following changes occur in boys: Infective diseases which are spread by sexual contact called sexually transmitted diseases (STDs). Question 21. Question 124. Refer to answer 42. Crossing over that occur during meiosis results in more variation, DNA replication also contributes to the variation. 10. Answer: Example, Amoeba and Plasmodium. This is a disc which is embedded in the uterine wall. (2020) Write the importance of such reproductions in nature. Question 35. 1. What are the advantages of vegetative propagation? Illustrate the following with the help of suitable diagrams: Leaf of Bryophyllum with buds. These differences are important for survival of species. What would be the ratio of chromosome number between an egg and its zygote? The stem is girdled, i.e., a ring of bark is removed and then it is covered with a moist moss or cotton and enclosed in a polythene bag. It increases the rate of the population of our country. (a) Ovary (b) Oviduct (c) Uterus The wild yeasts are repressed, which ensures a reliable and predictable fermentation. (i) Name the following: II. Describe sexually transmitted diseases and mention the ways to prevent them. Which of the following statements is correct? Change occurs in ovaries during menstruation cycle are-. (Delhi 2013) A lady with a developing embryo in her womb is termed as pregnant. Style is a tube which connects stigma to the ovary. Diaphragm (or Cap) is used by human females which is put over the cervix. The average gestation period in humans (or the average during of human pregnancy) is about nine months. Organisms such as Hydra use regenerative cells for reproduction in the process of budding. Dekkera/Brettanomyces is a genus of yeast known for its important role in the production of 'lambic' and specialty sour ales, along with the secondary conditioning of a particular Belgian Trappist beer. Question 51. Answer: Growth of hairs in new parts of the body such as armpits, between thighs near genital organ thin hairs on face, legs and on arms. (b) II and IV Ureter of each kidney leaves from the renal pelvis. The function of cotyledon is to store food for the future plant or embryo. The cutting of the stem which is grafted on the other plant is scion and the rooted plant on which the cutting is grafted is called stock. Refer to answer 120(b) for figure. Vegetative propagation is usually used for the propagation of those plants which produce either very few seeds or do not produce viable seeds. [14][20], By the late 18th century two yeast strains used in brewing had been identified: Saccharomyces cerevisiae (top-fermenting yeast) and S.carlsbergensis (bottom-fermenting yeast). Answer: [119] The yeast of the genus Zygosaccharomyces have had a long history as spoilage yeasts within the food industry. (ii) Refer to answer 68. In case of boys beard and mustache start appearing, voice begins to crack, reproductive organs develop and start producing releasing sperms. [NCERT Exemplar] Draw a schematic diagram to illustrate the changes that are likely to be observed during the development of new individuals in any one of the organisms named. These parts are termed as vegetative units or vegetative propagules. Question 16. (a) Leishmania and Plasmodium reproduce by fission (asexual mode of reproduction). (ii) Potato in the store room starts sprouting. Preventive measures: Use of condoms or similar coverings. Question 2. (i) Implantation of zygote (b) Ihe structures called spores (released from blobs) are present in sporangia which can develop into new Rhizopus individuals. (c) III and IV Name the causative agent of the disease Kala-azar and its mode of asexual reproduction. The zygote undergoes repeated mitotic divisions to form the embryo which has the potential to form a complete individual. Class 10 Science Chapter 8 How do Organisms Reproduce? is indeed a vital chapter for Board examinations. 2. The tiny blob-on-a-stick structures known as sporangia contain cells, or spores, that can eventually develop into new Rhizopus individuals. Answer: When the Amoeba cell has reached its maximum size of growth, then first the nucleus of Amoeba lengthens and divides into two parts. Because, during gestation period of pregnancy, menstruation does not take place. Carpel is made of three parts. (b) Name the parts of the human female reproductive system where, (i) fertilisation takes place (ii) implantation of the fertilised egg occurs. Or Number of chromosomes in both the gametes are equal hence a number of chromosomes in a female gamete of tobacco plant is 24. From the internet, gather information about the chromosome numbers of five animals and five plants. The causative organism of syphilis is Treponema pallidum and causative organism of gonorrhea is Nisseria gonorrhoeae. Chemical method is not meant for males: Use of these techniques helps in maintaining health of the woman. (v) Rhizopus (AI 2011) Answer: Where is the zygote located in the flower after fertilization? What is the importance of DNA copying in reproduction? Contraceptive methods may fall in following categories: Surgical methods such as vasectomy & tubectomey. (AI 2016) Answer: Reproduction is essentially a phenomenon that is not for the survival of an individual but for the stability of a species. Describe sexually transmitted diseases (STDs) and mention the ways to prevent them. Plants produced are genetically identical plants (clones) that have similar characteristics to the parent. (AI 2016) (c) Plasmodium Are you preparing for Exams? Write the functions of the following in human female reproductive system: Ovary, oviduct, uterus How does the embryo get nourishment inside the mothers body ? We hope this detailed article on NCERT Solutions For Class 10 Science Chapter 8 How Do Organisms Reproduce? (i) Ovary: The ovaries are primary sex organs (or female gonads), which perform the dual function : Where is the zygote located in the flower after fertilisation? IUCDs prevent implantation in the uterus. What is hymen? The ratio is 1 : 2 Sperms contain either X or Y chromosome whereas an egg will always have an X chromosome. [1][2][3] They are estimated to constitute 1% of all described fungal species.[4]. Growth of breasts and hair in axillae and over pubis. The yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols through the process of fermentation. The ovaries grow rapidly and ripen to form a fruit. Ans: In artificial vegetative propagation, an isolated plant structure called explants is cultivated in a glass container under aseptic conditions with proper nutrient medium. It is transmitted sexually or through exposure to contaminated blood. (b) Psychological reason These pieces or fragments grow into new individuals. Mention the site and product of fertilisation in a flower. Organism such as yeast use asexual reproduction process known as budding to reproduce new cells. (a) The age at which the sex hormones begin to be produced and the boy and girl becomes sexually mature, i.e., able to reproduce is called puberty. Another requirement is special organs like an erectile organ called penis and organs which can carry the baby for a long period. Refer to answer 17. Question 26. Binary fission is the division of adult parental body into two nearly equal daughter cells. 19. These plants are genetically identical. (b) (i) XX Female child This has occurred out of experimentation, as very little information exists regarding pure culture fermentative capabilities and the aromatic compounds produced by various strains. (c) Cracking of voice Write one difference in their mode of reproduction. If the egg is not fertilized and uterus does not get zygote, the developed lining slowly breaks and menstruation occur. After 4-5 days the zygote becomes a multicellular structure blastocyst. Syphilis is caused by bacteria. (ii) (a) Oviduct or fallopian tubes What are the changes seen in girls at the time of puberty ? (a) sepals Name the process. Variations are the basis for evolution. Question 7. Which among the following is not the function of testes at puberty? (b) The process of transfer of pollen grains from the anther of a flower to the stigma of the same flower or another flower is known as pollination. If the ovary does not get fertilized, its lining becomes thick and spongy. (ii) Oviduct (Fallopian tube): It is a site where egg and sperms meet and fertilisation takes place. List various reproductive parts of the flower. The DNA in the nucleus of a cell is the information source for making protiens. Yeasts of the genus Candida, another group of opportunistic pathogens, cause oral and vaginal infections in humans, known as candidiasis. What is the importance of reproduction? Name the male and female gametes in animals. In addition, Saccharomyces exiguus (also known as S.minor), a wild yeast found on plants, fruits, and grains, is occasionally used for baking. Ans: The labelled diagram of the longitudinal section of flower is as follows: 30. (a) Name the mode of reproduction of the following organisms and state the important feature of each mode : Characters that are transmitted from parents to offspring during reproduction show [NCERT Exemplar] (a) Threadlike non-reproductive structures present in Rhizopus. What is the number of chromosomes in the female gamete? Why is it used in horticulture practices? Uterus or womb The two testes lie in respective scrotal sacs. AIDS is caused by HIV virus and can be transmitted through infected blood, semen or vaginal fluid. [NCERT Exemplar] Fluffer R320. Filed Under: CBSE Tagged With: How Do Organisms Reproduce? In case of destruction of all organisms of one trophic level, the ecosystem will get unstable and eventually all life forms will die. Asexual reproduction is the mode of reproduction used by single organisms or parents without gamete production or fusion. Hence variation is beneficial to species, but not to the individuals. They also make uterus unsuitable for implantation and cervix hostile to sperms. [61] The taxonomy of the genus Brettanomyces has been debated since its early discovery and has seen many reclassifications over the years. Secondary sexual characters in male: Question 42. have seen an increasing use in the craft-brewing sector of the industry, with a handful of breweries having produced beers that were primarily fermented with pure cultures of Brettanomyces spp. The process of transfer of pollen grains from anther of a flower to the stigma of the same flower or another flower of the same species is known as pollination. [62] Shortly after, the formation of ascospores was observed and the genus Dekkera, which reproduces sexually (teleomorph form), was introduced as part of the taxonomy. (AI 2016) Sexually transmitted diseases caused by virus are : AIDS (Acquired Immunodeficiency Syndrome) and genital warts while caused by bacteria are gonorrhoea and syphilis. Plants produced by this method show no genetic variation. List three techniques that have been developed to prevent pregnancy. Early classification was based on a few species that reproduced asexually (anamorph form) through multipolar budding. Competition for food, predation is common in nature. It includes diaphragm, condom and intrauterine devices. Ans: Different methods of contraception are barrier method, chemical method and surgical method. [97], Yeast is often used by aquarium hobbyists to generate carbon dioxide (CO2) to nourish plants in planted aquaria. It is the fusion of male gamete with female gamete. (a) Refer to answers 88 (a)(i) and (b). Answer: But, they do not bear flowers and fruits. Intrauterine contraceptive device-These devices are implemented into uterus, e.g., copper T, to prevent fertilisation. Placenta provides a large surface area for glucose and oxygen, and nutrients to pass from the mothers blood to the embryo. Before getting into the details ofhow do organisms reproduce class 10 extra questions and answers, lets have an overview of topics and subtopics underNCERT Solutions For Class 10 Science Chapter 8 How Do Organisms Reproduce? nci INCI MARCHE 1FX Kum Rengi Erkek Marin Ayakkab esiz indirim ve taksit frsatlaryla instreet. They are produced in large numbers in the testes. Ans: Diagrammatic representation of binary fission in amoeba is as follows: 16. (b) Role of Gamete : Gametes are the reproductive cells involved in sexual reproduction having half of the chromosome. Question 14. Answer: Offsprings formed are clones. (b) Name the parts of the human female reproductive system where (i) fertilisation and (ii) implantation occur respectively. (i) Write the names of those parts of a flower which serve the same function as the following do in the animals: Katz Ezov et al. (d) pollen grains Germ free plants are produced by this method from virus infected plants. Name the parts 1 to 5. The correct sequence of organs in the male reproductive system for transport of sperms is, Answer is (a) testis vasdeferens urethra. Refer to answer 103. After a month or so, both parts unite with each other and a new plant develops from the scion. Ans: Essential requisites for sexual reproduction are transfer of germ cells either by external release of germ cells or by internal transfer of germ cells. In 1825, a method was developed to remove the liquid so the yeast could be prepared as solid blocks. Question 40. However, regeneration is not the same as reproduction, since most organisms would not normally depend on being cut up to be able to reproduce. (i) Testes An offspring formed by sexual reproduction has variations because it involves two parents; therefore the offspring has some characteristics of male and a few of female. DNA replication also ensures that same number of chromosomes are passed from parents to offspring. Yeasts are unicellular organisms that evolved from multicellular ancestors,[5] with some species having the ability to develop multicellular characteristics by forming strings of connected budding cells known as pseudohyphae or false hyphae. Offspring produced may differ in genetic make-up and variations occur. With the help of suitable diagrams, describe the mode of reproduction in Amoeba. No two individuals are absolutely alike in a population because sexual reproduction promotes diversity of characters in the offspring by providing genetic variation. (ii) State the function of flowers in the flowering plants: When the oxygen is depleted, fermentation begins, producing ethanol as a waste product; however, this evaporates during baking.[74]. (b) After implantation of zygote or embryo in the thick lining of the uterus, a disc-like special tissue develops between the uterus wall and the embryo, which is called as placenta. The tiny blob-on-a-stick structures known as sporangia contain cells, or spores, that can eventually develop into new Rhizopus individuals. The male gametes fertilise the female gametes. Question 45. Mammary glands (or breasts) develop and enlarge. Examples of cross pollination are plums, blackberries etc. Mention its advantages. (a) Single ceiled organisms reproduce through following ways: Answer: The rate Of birth and death in a given population determine its stability. Pollen grains reach stigma through various agencies like wind, water, insect, etc. Write two examples each of sexually transmitted diseases causes by (i) virus, (ii) bacteria. A couple wants to space the birth of their second child. The flower may be unisexual i.e. Dekkera/Brettanomyces spp. In some other,stems grow horizontally and develop root below and leaves above the ground. It is a disc shaped structure embedded in the uterine wall. For a healthy society, the male-female sex ratio must be maintained at almost the same level. Brettanomyces is a significant contributor to wine faults within the wine industry. The process of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. The fetus is connected to placenta in mothers body through umbilical cord. Also refer to answer 26. 31. Plants such as banana, orange, rose and jasmine are produced by vegetative propagation because they lose the capacity to produce seeds. Refer to answers 38 and 26. Answer: Now, as fertilization doesnt occur this lining is not needed. (i) It regulates the formation of sperms. Testes are responsible for synthesizing sperms and testosterone. What is funeral of unfertilised egg? Why cannot fertilisation take place in flowers if pollination does not occur? Ans: Two important functions of gonads are production of gametes in male and female and production of sex hormones. These two gametes combine to form the zygote and the original number of chromosomes is restored. Question 122. After implantation, a disc-like special tissue develops between the uterus wall (called uterine wall) and the embryo (or fetus), which is called placenta. List four points of significance of reproductive health in a society. (b) Sperms may not be able to survive under external environmental conditions for long. (ii) Name the parts of the human female reproductive system where What is the significance of pollination? Asexually reproducing organisms can suffer a dangerous lack of diversity but they can also reproduce faster than sexually reproducing organisms, and a single individual can found a new population without the need for a mate. This means only one egg is available for fertilization in one menstrual cycle. Which among the following statements arer true for sexual reproduction in flowering plants? (i) it has to receive a zygote. Regeneration is carried out by specialised cells. This disc remains embedded within the uterine wall and has villi on the embryos side of the tissue. The testis lies in a sac outside the abdominal cavity called scrotum. How will an organism be benefited if it reproduces through spores ? Answer: Some yeasts, including Schizosaccharomyces pombe, reproduce by fission instead of budding,[44] and thereby creating two identically sized daughter cells. Ans: In human beings testes produce male gametes sperm. The ovule develops a tough coat and is gradually converted into a seed. Fungi reproduce asexually by fragmentation, budding, or producing spores. Stock provides water and minerals from the soil to the developing plant. Testes are placed outside the body cavity in the scrotal sac because it requires a temperature 2C lower than the normal body temperature for production of sperms. (ii) This fluid protects the sperms from the acids present in the urethra. The unfertilised ovum dies within a day and the uterus lining also breaks down. (a) Function of human female reproductive part are as follows : The four methods of birth control which deliberately prevent fertilisation in humans are: Question 90. What is placenta ? (b) Female gamete/egg is not fertilised. Frequent pregnancy causes many health problems and also adds to an already exploding population. Why do offsprings formed by asexual reproduction exhibit remarkable similarity? In sexual reproduction, organisms produce gametes through meiosis, which is called reductional division, in which the original number of chromosomes becomes half. Justify. Each ureter is about 30 cm long, 3 4 mm in diameter and opens into urinary bladder by slit-like aperture. (Foreign 2014) Meiosis is a way of cell division in which a number of chromosomes get halved. (a) (i) Hydra Budding One egg is produced every month alternately by one of the ovaries. 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