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12. • Reproduction is a type of life process and it helps to prevent extinction of living r • at • • G l • • • • n • c • • e R s U a on e ti t • lu p • So a e h qu • organisms. Reproduction may be sexual or asexual. In asexual reproduction only one parent is involved and the cells divide mitotically. In sexual reproduction two parents are involved and the cells divide meiotically at the time of gametogenesis and mitotically after fertilization. Modes of asexual reproduction used by unicellular organisms are (1) binary fission (amoeba, paramoecium, euglena) (2) multiple fission (in amoeba during unfavourable condition) (3) budding (yeast) Modes of asexual reproduction in multicellular organisms are: ( 1) fragmentation (spirogyra) ( 2) regeneration (planaria) (3) budding (hydra) (4) vegetative propagation (through plant parts like stem, root or leaves) ( 5) spore formation (Mucor) The offsprings produced by asexual reproduction are genetically identical to the parents. Lack of genetic variation is the disadvantage while rapid reproduction is the advantage of asexual reproduction. In sexual reproduction, male parent produces male germ cells and female parent produces female germ cell or egg. Fertilization is the process in which male gamete (germ cell) fuses with the female gamete (germ cell) resulting in the formation of diploid zygote. Zygote develops into a new individual. Offsprings produced by sexual reproduction are different from parents. This variation enables organism to adapt and survive in the changing environment. It also helps to prevent the complete extinction of animal and plant species. Flower is a functional unit concerned with sexual reproduction in plants. The female reproductive part of a flower is carpel and the male reproductive parts is stamen. Pollination, fertilization and germination are the various process of sexual reproduction in plants. Human body is physically ready to reproduce at the age of 18 in girls and 21 in boys. Testes and penis are the main reproductive organs of the human male reproductive system. Testis produce sperms (male germ cells) and also secrete hormone testesteron which is responsible for changes in boys during puberty. Vagina, uterus, oviduct and ovaries are the main reproductive organs of the human female reproductive system. Ovaries develop and release eggs into the oviduct and also secrete hormone estrogen which brings about changes in girls during puberty. ni C The Life Cycle • • • SCIENCE & TECHNOLOGY - S.S.C. 135 • Fertilization, development and birth are various stages of sexual reproduction in human beings. • Limited family is advantageous to the individual as well as to the nation. • Contraceptive method use of condom not only protects the individual from STDs but also helps in population control. MULTIPLE CHOICE QUESTIONS (MCQ's) R (Each question carries one mark) s MCQ's BASED ON PRACTICALS To observe the Hydra bud clearly, Raju should see it first under the low power lens and then under high power lens in order to : 2. b wide area b budding So b iodine b budding 10. d none of these e b multiple fission c budding d none of these ni qu b paramoecium c yeast d euglena b yeast c spirogyra d mould An organism which can reproduce both by budding as well as regeneration is : a planaria b yeast c hydra d amoeba Binary fission in amoeba is called : U 9. c multiple fission The multicellular organism which reproduces by budding is : a hydra 8. d eosin Which of the following organisms doesn't reproduce by binary fission? a amoeba 7. c safranin Ramesh observed a slide of amoeba with elongated nuclei. It would represent : a binary fission 6. d all of these In Hydra the type of reproduction is : a binary fission 5. c spore formation To observe Amoeba and Paramoecium in a drop of water under microscope, the drop was taken on slide. The stain that will clearly show both of them is : a methylene blue 4. d all of these Which of the following is a mode of asexual reproduction? a fission 3. c more buds ti a less area lu 1. on Experiment : I. To study (A) binary fission in amoeba and (B) budding in yeast with the help of prepared slides. a simple binary fission b transverse binary fission c longitudinal binary fission d complex binary fission In binary fission : a cytoplasmic division is followed by nuclear division b nucleus divides into many nuclei c nuclear division is followed by cytoplasmic division d cyst bursts to release daughter cells The Life Cycle 136 Unique MCQ's MCQ's BASED ON CHAPTER Moderate Level 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. R s on ti 7. lu 6. So 5. e 4. qu 3. ni 2. Reproduction helps to : a maintain growth b keep organisms alive c prevent extinction d provide energy Longitudinal binary fission occurs in : a euglena c amoeba d hydra b paramoecium Cyst formation is one of the stages in : a binary fission c budding d regeneration b multiple fission Which of the following organisms reproduce by multiple fission? a amoeba c hydra d yeast b paramoecium The filament of spirogyra undergoes : a budding c binary fission d multiple fission b fragmentation In sweet potato, vegetative propagation takes place by means of : a roots c leaves d flowers b stems Bryophyllum plant reproduces by means of : a roots c leaves d spores b stems Male and female gametes fuses to form : a embryo c foetus d blastocyst b zygote Female reproductive part of a flower is : a stamen c carpel d filament b anther The male reproductive part of a flower is : a style c carpel d stigma b stamen Male germ cells or gametes are produced by : a ovary c sepal d pollen grains b filament The flower in its bud stage is protected by : a sepals c carpels d corolla b petals The transfer of pollen grains from anther to stigma is called : a ovulation c germination d fertilization b pollination The swollen part of the carpel at its bottom is called : a style c anther d ovary b stigma Which of the following serves as a nutritive tissue for the growing embryo within the ovule? a zygote c endosperm d ovule b ovary Which of the following develops into a seed? a ovule c endosperm d pollen grain b ovary Physical maturation of human reproductive system occurs in the stage of : a childhood c adolescence d old age b puberty In India, the minimum age of marriage for girls is : a 25 years c 18 years d 23 years b 21 years In human beings male gametes are produced by : a testis c epididymis d vas deferens b penis U 1. The Life Cycle SCIENCE & TECHNOLOGY - S.S.C. 20. 21. 22. Sperms are delivered to the site of fertilization by : a vagina c penis b testis d vas deferens Which of the following is a function of uterus? a secrete hormone testesteron b release eggs into the oviduct c secrete hormone estrogen d accommodate the growing foetus During child birth, a baby comes out of the woman's body through : a vagina c oviduct d ovary b vas deferens The thread like structures of mucor that spread on the surface of a slice of bread are called : a stems c rhizoids b roots d hyphae World population day is observed on : a August 22 c March 21 b July 11 d June 5 Anther produces : a spores c pollen grains b pollen tube d ovules 25. 4. 5. 6. 7. 8. 9. 10. lu So e 3. ni qu 2. Offsprings of asexual reproduction looks similar because : a it involves two parents b it involves only one parent c it involves gametes d it involves meiosis Mitosis occurs in : a plant cells c somatic cells b animal cells d germ cells Which of the following is the disadvantage of asexual reproduction? a rapid reproduction b lack of genetic variation c rapid growth d no fusion of two different cells Plants produced by vegetative propagation : a bear more flowers and fruits b bear less flowers and fruits c take less time to grow d take more time to grow Dolly sheep was the first mammal to be cloned from an : a embryo c adult tissue b adult cell d egg Union of male and female gametes takes place in : a meiosis c fertilization b mitosis d cloning Petals of flowers are usually bright coloured. Why? a to protect reproductive organs b to prevent cross pollination c to attract stray animals d to attract insects for pollination Pollen grain is transferred from one flower to a flower of another plant of the same species in : c geitonogamy a self pollination d cross pollination b autogamy Which of the following is not an agent of cross pollination in plants? a wind c water b temperature d animals Which of the following is a human male reproductive hormone? a testesteron c progesteron b estrogen d thyroxin U 1. ti Elementary Level on 24. s R 23. 137 The Life Cycle 138 11. Unique In a human sperm cell, genetic information is stored in : a mitochondria 12. c tail b head d middle part The female hormone estrogen is secreted by : a testis 13. c ovaries b uterus d oviducts Which of the following contraceptive method protects a person from STDs? a oral pills c copper-T b surgery d condoms Genetic variations enable organisms to : b reproduce rapidly c adapt and survive d restore the number of chromosomes ti a extinct completely Which of the following is an advantage of sexual reproduction? a genetic variation b genetic similarity 7. a style, stamen and filament b stamen, anther and stigma c style, stigma and ovary d stigma, ovary and stamen e The movement of pollen grains towards ovary is in the order : a style stigma anther ovary b stigma style anther ovary c anther style stigma ovary d anther stigma style ovary qu 6. Carpel is made up of : d lack of variety and diversity So c complete extinction of organisms 5. d germination lu 4. c fertilization b meiosis d bryophyllum on Haploid gametes are formed in : a mitosis 3. c spirogyra b hibiscus s Which of the following plants doesn't reproduce asexually? a cycas 2. R Complex Level 1. MCQ's The correct sequence of the movement of sperms towards penis is : ni a epididymis vas deferens urethra testis penis b testis urethra epididymis vas deferens penis U c epididymis testis vas deferens urethra penis d testis epididymis vas deferens urethra penis 8. 9. Identical twins are formed from : a single fertilized egg b single gamete c two fertilized eggs d two zygotes Which of the following is not an STD? a syphilis 10. b gonorrhea c AIDS d hepatitis Spore formation is the most common asexual method of reproduction in : a algae b fungi c bacteria The Life Cycle d protozoa SCIENCE & TECHNOLOGY - S.S.C. a flowers, leaves and stems b roots, stems and flowers c roots, stems and leaves d leaves, flowers and fruits Which of the following is not a part of human male reproductive system? a vas deferens The number of chromosomes present in a human germ cell (gamete) is : a 26 14. c 46 b 23 a creation of a young one b creation of an embryo c creation of a zygote d creation of a DNA copy Which life process is shown in the picture alongside? ti a respiration b excretion lu c nutrition So d reproduction 2. d 52 Which of the following is the basic process in reproduction? Mysterious Level 1. d seminal vesicle R 13. c cervix b epididymis s 12. In vegetative propagation, new plants are formed from : on 11. 139 Which of the following is incorrect regarding the process reproduction? a DNA copies are similar to the original e b DNA copies are not identical to the original c DNA copies are similar and identical to the original 3. ni qu d DNA copies are similar but not identical to the original The unicellular organism which reproduces asexually is : a spirogyra 5. d hydra Regeneration is not the same as reproduction because : a new organisms are not produced b it occurs only in micro-organisms c it occurs only when animal body gets cut d it occurs only when animal body matures U 4. c euglena b planaria In the figure given alongside the part marked 'A' is : a sporangium b sporogenesis c megasporophyll d spores The Life Cycle 140 7. Which of the following reproductive organ is common in humans as well as flowering plants? a anther c ovary d style b epididymis In human males, testes are located outside the abdominal cavity in the scrotum because : a it is easy to deliver the sperms b it helps to produce ejaculatory fluid c sperms require temperature lower than the normal body temperature d sperms require temperature higher than the normal body temperature Which of the following is an incorrect statement? a at birth the ovary of a baby girl contains 2 - 4 million eggs b at puberty, thousands of new eggs are formed in the girl's ovary c at puberty, a woman's ovaries usually release one egg each month d Ageing of eggs can cause defects in the children born to older women Which of the following is the function of umbilical cord? a supply oxygenated blood b remove deoxygenated blood c supply nutrients and oxygen d remove waste products The number of chromosomes in parents and their offsprings remains constant due to the formation : a haploid gametes b diploid gametes c diploid zygote d haploid gametes and diploid zygote The correct sequence of events in sexual reproduction in a plant is : a fertilization pollination meiosis germination b pollination fertilization meiosis germination c meiosis pollination fertilization germination d fertilization meiosis pollination germination 12. ti lu So 11. e 10. In the figure given alongside, the parts marked as A, B and C are sequentially : qu 9. on s 8. MCQ's R 6. Unique a stigma, filament and petal b style, anther and sepal A c pollen tube, anther and sepal d pollen tube, anther and petal ni C Which of the following is a change in boys that shows sexual maturity at puberty? a increase in weight b increase in height c cracking of voice d loss of milk teeth The ratio of number of chromosomes in a human egg and zygote is : a 1:2 c 1:3 d 3:1 b 2:1 Which of the following is not a function of ovaries in human female? a secrete hormones which bring changes in girls at puberty b secrete hormone estrogen c provides the route for the sperms to enter d develop and release eggs U 13. B 14. 15. The Life Cycle SCIENCE & TECHNOLOGY - S.S.C. 141 Answers MCQ's BASED ON PRACTICAL SKILLS 1 - a 2 - d 3 - a 4 - b 5 - a 6 - c 7 - a 8 - c 9 - a 10 - c a 3 - b 4 - a 5 - b 6 - a 7 - c 8 - b 9 - c 10 - b 11 - d 12 - a 13 - b 14 - d 15 - c 16 - a 17 - b 18 - c 19 - a 20 - c 21 - d 22 - a 23 - d 24 - b 25 - c 1 - b 2 - c 3 - b 4 - c 5 - b 6 - c 7 - d 8 - d 9 - b 10 - a 11 - b 12 - c 13 - d 1 - a 2 - b 3 - c 4 - a 5 - c 6 - d 7 - d 8 - a 9 - d 10 - b 11 - c 12 - c 13 - b 14 - d ni qu ti 1 - d 2 - c 3 - c 4 - c 5 - a 6 - c 7 - c 8 - b 9 - c 10 - d 11 - c 12 - b 13 - c 14 - a 15 - c U Mysterious Level s - on 2 e Complex Level - c lu Elementary Level 1 So Moderate Level R MCQ's BASED ON CHAPTER The Life Cycle