Class 10 Science · Chapter 7
Short answer:
NCERT Class 10 Science Chapter 7 How do Organisms Reproduce? ke complete solutions — 12 in-text questions (teenon page-wise sets) aur 11 exercise questions, sab NCERT ke exact order me, Hinglish explanation ke saath. Chapter cover karta hai: reproduction me DNA copying ka role aur variation kyun banti hai; asexual reproduction ke saare modes — fission (binary aur multiple), fragmentation, regeneration, budding, spore formation, vegetative propagation aur tissue culture; flowering plants me sexual reproduction — flower ke parts, pollination (self aur cross), fertilisation, seed aur fruit banna, germination; human reproduction — puberty ke changes, male aur female reproductive system, fertilisation, placenta se embryo ka nourishment, menstruation; aur reproductive health — contraception ke methods (barrier, hormonal, IUD/copper-T, surgical), STDs, aur female foeticide ka issue. Saath me asexual reproduction methods ka reference table, 6 common exam mistakes, board-style practice questions aur FAQs.
Reproduction hi ek aisa life process hai jo individual organism ke apne survival ke liye zaroori nahi hai — lekin species ke survival ke liye bilkul zaroori hai. Nutrition, respiration, excretion — ye sab agar ruk jaayein to organism mar jaata hai. Reproduction ruk jaaye to organism zinda rehta hai, par uski species khatam ho jaati hai. Isliye NCERT is chapter ko ek simple sawaal se shuru karta hai: reproduction hota kaise hai, aur jo bachcha banta hai woh parent jaisa bilkul kyun nahi hota?
Iska jawab DNA me hai. Har reproduction ke pehle cell apne DNA ki copy banata hai. Ye copying kaafi accurate hai — isliye offspring parent jaisa dikhta hai — par 100% accurate nahi. Chhoti-chhoti variations reh jaati hain. Asexual reproduction me sirf ek parent hota hai, isliye offspring bilkul parent jaisa hota hai — variation na ke barabar. Sexual reproduction me do parents ka DNA milta hai, isliye variation kaafi zyada. Aur yahi variation species ko badalte hue environment me bachaati hai — evolution ka raw material hai.
Chapter ka baaki hissa isi idea ko detail me le jaata hai — pehle single organisms ke asexual modes, phir flowering plants ka sexual reproduction, phir human reproductive system, aur last me reproductive health.
Chapter 7 Summary — 5 Minute Revision
1. Reproduction aur DNA copying
- Reproduction = organism ka apne jaisa naya individual banana. Ye individual ke survival ke liye zaroori nahi, par species ke survival ke liye zaroori hai.
- Cell ke nucleus me DNA (Deoxyribonucleic acid) hota hai — yahi information source hai jo body design (blueprint) decide karta hai.
- Reproduction ka basic event = DNA ki copy banana. Iske saath cell apne organelles aur cellular apparatus ki bhi ek extra copy banata hai, phir cell do me baant jaata hai.
- DNA copying kabhi bhi perfectly accurate nahi hoti — chhoti variations aati hain. Zyada bada change ho jaaye to naya DNA copy survive nahi karta aur cell mar jaata hai.
2. Variation ki importance
- Har species ek particular niche (habitat + role) me rehti hai. Niche kabhi bhi badal sakta hai — temperature, water level, food supply.
- Agar poori population bilkul ek jaisi ho aur environment drastically badal jaaye, to poori population khatam ho sakti hai (jaise heat-sensitive bacteria + global temperature rise).
- Agar variations hain, to kuch individuals naye conditions me survive kar jaate hain → species bach jaati hai.
- Yaad rakho: variation species ke liye faydemand hai; har individual ke liye zaroori faydemand nahi (kuch variations useless ya harmful bhi ho sakti hain).
- Variation hi evolution ka base hai.
3. Asexual reproduction — modes
- Fission — unicellular organisms me. Cell do ya zyada hisson me baant jaata hai.
- Binary fission: ek cell se do daughter cells. Amoeba (koi bhi plane), Leishmania (whip ke base se definite plane), Paramecium, bacteria.
- Multiple fission: ek cell ek saath bahut saare daughter cells me toot jaata hai. Plasmodium (malarial parasite). Cyst ke andar hota hai — favourable conditions aane par cyst toot jaata hai.
- Fragmentation — simple multicellular organism tootkar tukdon me baant jaata hai, har tukda badhkar naya individual banta hai. Example: Spirogyra.
- Regeneration — kat jaane par organism kate hue hisse se poora organism bana leta hai. Specialised cells proliferate karke different cell types aur tissues banate hain. Example: Hydra, Planaria. Ye normal reproduction nahi hai — ye sirf tab kaam aata hai jab organism accidentally kat jaaye.
- Budding — parent body par ek chhoti bud (kali) nikalti hai, badhkar alag ho jaati hai. Example: Hydra (regenerative cells se), Yeast.
- Spore formation — Rhizopus (bread mould) me hyphae ke upar sporangia (blob-on-a-stick) bante hain, jinme spores hote hain. Spores par thick wall hoti hai jo unhe unfavourable conditions me bachaati hai. Moist surface milte hi germinate ho jaate hain.
- Vegetative propagation — plants me root, stem, leaf jaise vegetative parts se naye plant banna.
- Roots: sweet potato, dahlia | Stems: potato (eyes se), ginger, sugarcane | Leaves: Bryophyllum (leaf ke notches me buds)
- Artificial methods: layering, grafting, cutting, aur tissue culture.
- Tissue culture — plant ke growing tip se tissue/cells lekar nutrient medium me grow karaate hain → callus banta hai → hormone medium me daalne par plantlets ban jaate hain → pot me transfer. Ornamental plants me common.
4. Vegetative propagation ke advantages
- Banana, orange, rose, jasmine — inme viable seeds nahi ya bahut kam bante hain, isliye vegetative propagation hi ekmatra tareeka hai.
- Naye plant seed se ugne wale plant se jaldi flower aur fruit dete hain.
- Sab plants genetically parent ke identical copies (clones) hote hain — desirable quality exactly preserve rehti hai.
5. Sexual reproduction — basic idea
- Do individuals ka DNA milta hai → offspring me naye combinations → zyada variation.
- Agar dono parents apna poora DNA de dein to har generation me DNA double ho jaata. Isliye germ cells (gametes) me DNA ki aadhi maatra hoti hai. Fertilisation par dono aadhe-aadhe milkar poora set banate hain.
- Gametes: ek chhota aur motile (male gamete), doosra bada aur food store karne wala + immobile (female gamete).
6. Flowering plants me sexual reproduction
- Flower ke 4 whorls: sepals, petals, stamens, carpel.
- Stamen = male part. Anther (pollen grains banata hai, yellowish powder) + filament.
- Carpel/Pistil = female part. Stigma (top, sticky — pollen yahan aata hai) + style (tube) + ovary (base, jiske andar ovules hote hain; har ovule me ek egg cell).
- Unisexual flower: sirf stamens ya sirf carpel (papaya, watermelon). Bisexual flower: dono (hibiscus, mustard).
- Pollination = pollen ka anther se stigma tak pahunchna.
- Self-pollination: usi flower ya usi plant ke doosre flower par.
- Cross-pollination: doosre plant ke flower par — agents: wind, water, animals (insects, birds).
- Fertilisation = male germ cell aur female germ cell (egg) ka fusion → zygote. Pollen stigma par germinate hokar pollen tube banata hai jo style se hoke ovule tak pahunchta hai.
- Fertilisation ke baad: zygote → embryo; ovule → seed; ovary → fruit. Petals, sepals, stamens, style aam taur par sookh kar gir jaate hain.
- Germination = seed se naya plant nikalna (cotyledons food supply dete hain).
7. Human beings me reproduction — puberty
- Human sexually reproduce karte hain. Reproductive maturity ki age = puberty (adolescence).
- Dono me common changes: armpits aur genital area me thin hair, arms/legs/face par bhi baal, skin oily ho jaana, pimples.
- Girls me: breast size badhna aur breast ki skin ka darker hona, menstruation shuru hona.
- Boys me: face par baal (beard/moustache) aana, awaaz ka bhaari (deep) hona, penis ka occasional enlargement.
8. Male reproductive system
| Part | Function |
|---|---|
| Testes (scrotum me, body ke bahar) | Sperms banate hain; testosterone hormone banate hain (male sex hormone → sperm production + puberty changes). Bahar isliye taaki temperature body se kam rahe — sperm formation ke liye zaroori. |
| Vas deferens | Sperms ko testes se aage le jaata hai; urethra se milkar common passage banata hai. |
| Seminal vesicles | Sperms ko fluid dete hain — nourishment (fructose) aur movement asaan. |
| Prostate gland | Seminal vesicles ke saath fluid add karti hai → sperm + fluid = semen. Isse sperms transport ho paate hain aur active rehte hain. |
| Urethra / Penis | Semen (aur urine) ka common passage; semen ko female body me deliver karta hai. |
↔ Table ko side me swipe karein
9. Female reproductive system
| Part | Function |
|---|---|
| Ovaries (do) | Egg (ovum) banati hain — girl ke janm ke waqt hi hazaaron immature eggs present hote hain. Puberty ke baad har month ek ovary ek mature egg release karti hai. Female hormones (oestrogen, progesterone) bhi banati hain. |
| Fallopian tube / Oviduct | Egg ko ovary se uterus tak le jaati hai. Fertilisation yahin hota hai. |
| Uterus (womb) | Fertilised egg (zygote) yahan implant hota hai aur embryo develop hota hai. |
| Cervix | Uterus ka neeche ka mouth, jo vagina me khulta hai. |
| Vagina | Sperms yahan se enter karte hain; baby birth ke waqt yahin se bahar aata hai. |
↔ Table ko side me swipe karein
10. Fertilisation, placenta aur menstruation
- Sexual intercourse ke dauran semen vagina me jaata hai. Sperms upar jaakar fallopian tube me egg se milte hain → fertilisation → zygote.
- Zygote divide hokar embryo banta hai, uterus me utarta hai aur uterus ki thick lining me implant ho jaata hai.
- Placenta — embryo aur uterus wall ke beech ka disc-like special tissue. Embryo ki taraf villi hote hain jo surface area badhate hain; mother ki taraf blood spaces hote hain jo villi ko gher lete hain.
- Mother ke blood se glucose aur oxygen embryo tak jaate hain.
- Embryo ke waste products placenta ke through mother ke blood me transfer hokar nikal jaate hain.
- Mother ke andar development ka time (gestation) lagbhag nau mahine. Uterus ke rhythmic contraction se child birth hota hai.
- Menstruation — har month uterus ki lining fertilised egg receive karne ke liye thick aur spongy ho jaati hai (blood supply ke saath). Agar fertilisation nahi hota, to ye lining ki zaroorat nahi rehti — woh slowly toot kar blood aur mucous ke roop me vagina se bahar aati hai. Ye cycle lagbhag 28 din ka hota hai, bleeding ~2-8 din. Pehli baar puberty pe shuru hoti hai, menopause par rukti hai.
11. Reproductive health
- Sexually transmitted diseases (STDs):
- Bacterial — gonorrhoea, syphilis
- Viral — warts, HIV-AIDS (ye doosre routes se bhi failta hai)
- Contraception ke methods:
- Barrier methods: condom (male), cervical cap/diaphragm (female) — sperm ko egg tak pahunchne se rokte hain. Condom STDs se bhi bachaata hai.
- Chemical/hormonal methods: oral pills — hormonal balance badalkar egg release (ovulation) rokti hain. Side effects ho sakte hain.
- Intra-uterine devices (IUD): Copper-T / loop — uterus me lagaya jaata hai, pregnancy rokta hai. Kuch women me side effects (irritation, bleeding).
- Surgical methods: males me vasectomy (vas deferens block/cut), females me tubectomy (fallopian tube block/cut). Permanent hain; safe hain par infection ka risk agar theek se na kiya jaaye.
- Contraception apnaane ke reasons: family size control, maa ki sehat aur do bachchon ke beech gap, STDs se suraksha, population growth control.
- Female foeticide — prenatal sex determination karke female foetus ko girana. Ye gair-kanooni (illegal) hai aur isse sex ratio bigadta hai. Reproductive health ka ye ek serious social issue hai.
12. Reproduction aur population stability
- Reproduction se hi ek species generation dar generation continue rehti hai — mar rahe individuals ki jagah naye individuals lete hain, isliye population size stable rehta hai.
- DNA copying reliable hone ki wajah se body design ki similarity bani rehti hai — species ki identity maintain rehti hai.
- Saath hi thodi variation aati rehti hai, jo species ko badalte environment me survive karne deti hai.
In-Text Questions — Solutions
Q1. What is the importance of DNA copying in reproduction?
DNA (Deoxyribonucleic acid) cell ke nucleus me hota hai aur yahi information source hai jo body design ka blueprint rakhta hai. Reproduction ke waqt DNA ki copy banna isliye zaroori hai:
- Isse offspring ko parent jaisa body design milta hai — species ki identity generation dar generation bani rehti hai.
- Har cell ko apne ek complete DNA set ki zaroorat hoti hai taaki woh proteins bana sake aur theek se kaam kar sake.
- DNA copying kabhi 100% accurate nahi hoti — isliye chhoti-chhoti variations aati hain. Yahi variations species ke survival aur evolution ka base hain.
Yaani DNA copying ek saath do kaam karti hai — similarity bhi deti hai aur variation bhi.
Q2. Why is variation beneficial to the species but not necessarily for the individual?
Har species ek particular niche (habitat + uska role) me rehti hai. Ye niche kabhi bhi badal sakta hai — temperature badh sakta hai, paani sookh sakta hai, food khatam ho sakta hai.
- Species ke liye faydemand: agar population me variations hain, to naye conditions aane par kuch individuals aise honge jo un conditions me survive kar lenge. Isse poori species khatam hone se bach jaati hai. Jaise heat-resistant variation wale bacteria global temperature badhne par bach jaate hain.
- Individual ke liye zaroori faydemand nahi: koi bhi ek variation us particular individual ke liye useful, useless ya harmful — kuch bhi ho sakti hai. Ek variation tabhi 'useful' kehlaati hai jab environment usko suit kare. Environment na badle to woh variation individual ko koi fayda nahi deti.
Isliye variation ka fayda population level par dikhta hai, individual level par nahi.
Q1. How does binary fission differ from multiple fission?
| Binary fission | Multiple fission |
|---|---|
| Parent cell do daughter cells me baantta hai. | Parent cell ek saath bahut saare daughter cells me baantta hai. |
| Nucleus pehle ek baar divide hota hai, phir cytoplasm baantta hai. | Nucleus baar-baar divide hokar kai nuclei banata hai, phir har nucleus ke around cytoplasm baant jaata hai. |
| Aam taur par favourable conditions me hota hai. | Aksar unfavourable conditions me cyst ke andar hota hai; conditions theek hone par cyst toot kar sab daughter cells release karta hai. |
| Example: Amoeba, Leishmania, Paramecium, bacteria | Example: Plasmodium (malarial parasite) |
↔ Table ko side me swipe karein
Q2. How will an organism be benefited if it reproduces through spores?
Spore formation (jaise Rhizopus — bread mould) se organism ko ye fayde milte hain:
- Ek baar me bahut zyada number me spores bante hain (sporangia ke andar), isliye reproduction rate bahut high hoti hai.
- Spores par thick protective wall hoti hai jo unhe garmi, sookha aur doosri unfavourable conditions me marne se bachaati hai — organism bura time survive kar leta hai.
- Spores bahut halke hote hain, isliye hawa se door tak fail jaate hain — naye habitats mil jaate hain aur competition kam hota hai.
- Moist surface milte hi germinate hokar naya organism ban jaate hain.
Q3. Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Complex (higher) organisms me regeneration se poora naya individual nahi ban sakta, kyunki:
- Unka body design bahut complex aur highly specialised hota hai — alag-alag organs alag-alag kaam karte hain aur ek doosre par depend karte hain (heart, brain, lungs, kidney).
- Unke cells specialised ho chuke hote hain; woh divide hokar har type ke cell aur organ banane ki capacity kho dete hain.
- Regeneration ke liye chahiye specialised (undifferentiated) cells jo Hydra aur Planaria jaise simple organisms me hote hain — ye cells proliferate karke sabhi cell types aur tissues bana lete hain.
- Complex organism ka ek kata hua tukda apne aap me poora organ system nahi rakhta, isliye woh zinda hi nahi reh sakta.
Note: complex organisms me healing (wound bhar jaana, skin/liver ka partial repair) hota hai, par usse naya individual nahi banta.
Q4. Why is vegetative propagation practised for growing some types of plants?
- Kai plants — banana, orange, rose, jasmine — me viable seed nahi banta ya bahut kam banta hai. Unko ugane ka ekmatra practical tareeka vegetative propagation hai.
- Aise plants seed se ugne wale plants ki tulna me jaldi flower aur fruit dete hain, kyunki poora plant body already develop ho chuka hota hai.
- Naye plants parent ke genetically identical clones hote hain — isliye achhi quality (taste, colour, disease resistance) exactly waisi hi milti hai.
- Kam samay me bade paimane par identical plants taiyaar kiye ja sakte hain (tissue culture, cutting, layering, grafting).
Q5. Why is DNA copying an essential part of the process of reproduction?
DNA hi woh information source hai jisme organism ka body design likha hota hai. Reproduction ka matlab hi hai apne jaisa naya individual banana — aur wo tabhi possible hai jab naye cell ko DNA ki poori copy mile.
- DNA copy hone se hi offspring me parent jaise characters transfer hote hain — species ki identity bani rehti hai.
- Har naye cell ko apna DNA chahiye taaki woh apne proteins bana sake aur functional rahe. Bina DNA copy ke daughter cell zinda nahi reh sakta.
- Copying me hone wali chhoti errors/variations species ko badalte environment me survive karne aur evolve hone ka mauka deti hain.
Q1. How is the process of pollination different from fertilisation?
| Pollination | Fertilisation |
|---|---|
| Pollen grains ka anther se stigma tak transfer hona. | Male germ cell aur female germ cell (egg) ka fusion. |
| Fertilisation se pehle hoti hai — ek physical transfer process hai. | Pollination ke baad hoti hai — ek cellular fusion process hai. |
| External agents ki zaroorat: wind, water, insects, birds. | Koi external agent nahi — pollen tube ke andar hi hota hai. |
| Do types: self-pollination aur cross-pollination. | Result: zygote banta hai, jo aage embryo banta hai. |
↔ Table ko side me swipe karein
Pollen stigma par germinate hokar pollen tube banata hai, jo style se hote hue ovary ke ovule tak pahunchta hai — wahan fertilisation hota hai.
Q2. What is the role of the seminal vesicles and the prostate gland?
Seminal vesicles aur prostate gland apne secretions ko vas deferens se guzarte sperms me add karte hain. Sperm + in glands ka fluid = semen.
- Ye fluid sperms ko ek liquid medium deta hai jisme unka transport asaan ho jaata hai — sperms ki movement behtar hoti hai.
- Fluid me nutrition (fructose jaise sugars) hoti hai jisse sperms ko energy milti hai aur woh active rehte hain.
- Ye female reproductive tract ke acidic environment ko neutralise karne me bhi madad karta hai.
Q3. What are the changes seen in girls at the time of puberty?
Puberty par ladkiyon me ye changes dikhte hain:
- Armpits aur genital area me patle baal aana; haathon, pairon aur chehre par bhi thin hair.
- Skin oily ho jaana aur pimples nikalna.
- Breast size badhna aur breast ke nipple ki skin ka rang gehra (darker) hona.
- Menstruation shuru hona (menarche) — ovaries se har mahine egg release hone lagta hai.
- Reproductive organs ka mature hona; height aur body shape me badlav; emotional/behavioural changes.
Q11. How does the embryo get nourishment inside the mother's body?
Embryo ko nourishment placenta ke through milta hai.
- Placenta ek disc-like special tissue hai jo embryo aur uterus ki wall ke beech develop hota hai.
- Embryo ki taraf placenta par villi (ungli jaise projections) hote hain — inse absorption ka surface area bahut badh jaata hai.
- Mother ki taraf blood spaces hote hain jo in villi ko gher lete hain.
- Mother ke blood se glucose aur oxygen placenta ke through embryo tak pahunchte hain.
- Isi tarah embryo ke waste products placenta ke through mother ke blood me chale jaate hain aur mother ke body se excrete ho jaate hain.
Q5. If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases?
Nahi. Copper-T (IUD) sirf ek contraceptive device hai — ye uterus me lagaya jaata hai aur pregnancy rokta hai.
- Ye sexual contact ke dauran body fluids ke exchange ko nahi rokta.
- Isliye ye gonorrhoea, syphilis, warts ya HIV-AIDS jaise STDs se koi suraksha nahi deta.
- STDs se bachne ke liye barrier method — condom ka istemaal zaroori hai, kyunki wahi body fluids ke direct contact ko rokta hai.
Poore Class 10 Science ke handwritten colour notes
IITian & district toppers ke banaye short notes — revision-ready, diagram ke saath. Board se pehle poora syllabus 3 din me revise.
Exercise Questions — Solutions (Q1–Q11)
Q1. Asexual reproduction takes place through budding in:
(a) amoeba (b) yeast (c) plasmodium (d) leishmania
Answer: (b) yeast
Yeast me parent cell par ek chhoti bud nikalti hai, jo badhkar alag ho jaati hai aur naya yeast cell ban jaati hai. Kabhi-kabhi buds alag hone se pehle hi apni bud nikaal lete hain — chain ban jaati hai.
Baaki options: Amoeba aur Leishmania = binary fission; Plasmodium = multiple fission.
Q2. 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
Vas deferens male reproductive system ka part hai — ye sperms ko testes se urethra tak le jaata hai.
Ovary (egg banati hai), Fallopian tube (egg ko uterus tak le jaati hai, fertilisation ki jagah) aur Uterus (embryo develop hota hai) — teenon female reproductive system ke parts hain.
Q3. The anther contains:
(a) sepals (b) ovules (c) carpel (d) pollen grains
Answer: (d) pollen grains
Anther stamen (male reproductive part) ka upar wala hissa hai, jisme pollen grains bante hain — yahi yellowish powder hai jo male germ cells rakhta hai.
Ovules ovary ke andar hote hain (carpel ka part), sepals sabse bahar ka whorl hai, aur carpel khud female reproductive part hai.
Q4. What are the advantages of sexual reproduction over asexual reproduction?
- Zyada variation: DNA do alag parents se aata hai, isliye offspring me genes ke naye combinations bante hain. Asexual me offspring parent ki almost exact copy hota hai.
- Better survival: variation ki wajah se badalte environment me kuch individuals survive kar jaate hain — species khatam hone se bach jaati hai.
- Evolution possible: sexual reproduction se paida hui variations natural selection ka raw material banti hain, jisse nayi species ban sakti hain.
- Errors ka kam accumulation: do parents ke DNA milne se genetic defects utne aasani se poori population me fix nahi hote.
- Do parents ke useful characters ek hi offspring me aa sakte hain — improved varieties possible.
Q5. What are the functions performed by the testis in human beings?
Testes (testis ka plural) ke do main functions hain:
- Sperm production: testes male germ cells yaani sperms banate hain.
- Hormone production: testes testosterone (male sex hormone) banate hain, jo (i) sperm production regulate karta hai aur (ii) puberty ke changes laata hai — chehre par baal, awaaz ka bhaari hona, reproductive organs ka development.
Extra point: testes body cavity ke bahar scrotum me hote hain, kyunki sperm formation ke liye body temperature se kam temperature chahiye.
Q6. Why does menstruation occur?
Puberty ke baad har mahine ek ovary se ek mature egg release hota hai. Uske saath hi uterus ki lining fertilised egg ko receive karne ke liye moti aur spongy ho jaati hai, aur usme rich blood supply develop ho jaati hai — taaki embryo implant hokar nourishment le sake.
Agar egg fertilise nahi hota, to is thick lining ki koi zaroorat nahi rehti. Tab woh lining dheere-dheere toot kar blood aur mucous ke roop me vagina ke through bahar aati hai. Isi ko menstruation kehte hain.
- Cycle lagbhag 28 din ka hota hai; bleeding aam taur par 2 se 8 din chalti hai.
- Ye puberty par shuru hoti hai (menarche) aur menopause par band ho jaati hai.
- Yaani menstruation ka matlab hai — us mahine pregnancy nahi hui.
Q7. Draw a labelled diagram of the longitudinal section of a flower.
Flower ke longitudinal section me ye parts label karne hote hain (bahar se andar ki taraf):
- Sepal — sabse bahar ka green whorl, kali (bud) ki suraksha karta hai
- Petal — rangeen whorl, insects ko attract karta hai
- Stamen (male part) = Anther (pollen grains banata hai) + Filament (danthal)
- Carpel / Pistil (female part) = Stigma (chipchipa top, pollen yahan aata hai) + Style (tube jo stigma ko ovary se jodta hai) + Ovary (phoola hua base)
- Ovule — ovary ke andar; har ovule me ek egg cell (female germ cell) hota hai
- Receptacle / Thalamus — flower ka base jahan saare whorls jude hote hain
Diagram tips (marks bachane ke liye):
- Pencil se saaf, single lines banao; shading mat karo.
- Ovary ko cut open dikhao taaki andar ke ovules dikhein — longitudinal section ka yahi matlab hai.
- Label lines straight aur bina arrow ke ho; labels diagram ke ek hi taraf, horizontal likhe.
- Diagram ke neeche title likho: Longitudinal section of a flower.
Q8. What are the different methods of contraception?
Contraception ke chaar main types hain:
| Method | Kaise kaam karta hai | Example |
|---|---|---|
| Barrier method | Sperm ko egg tak physically pahunchne se rokta hai | Condom (male), cervical cap / diaphragm (female) |
| Chemical / Hormonal method | Hormonal balance badalkar egg release (ovulation) rokta hai | Oral contraceptive pills; ye side effects de sakti hain |
| Intra-uterine device (IUD) | Uterus me lagaya jaata hai, implantation/pregnancy rokta hai | Copper-T, loop; kuch women me irritation ya bleeding |
| Surgical method | Gametes ke rasta permanently block kar dena | Vasectomy (males — vas deferens block/cut), Tubectomy (females — fallopian tube block/cut) |
↔ Table ko side me swipe karein
Important: in sab me sirf condom (barrier method) hi STDs se bhi bachaata hai — baaki methods sirf pregnancy rokte hain.
Q9. How are the modes for reproduction different in unicellular and multicellular organisms?
| Unicellular organisms | Multicellular organisms |
|---|---|
| Poora organism hi ek cell hai, isliye cell division hi reproduction hai. | Body me specialised cells, tissues aur organs hote hain; reproduction ke liye alag reproductive organs/tissues hote hain. |
| Modes: binary fission (Amoeba, Leishmania), multiple fission (Plasmodium), budding (Yeast). | Modes: fragmentation (Spirogyra), regeneration (Planaria, Hydra), budding (Hydra), spore formation (Rhizopus), vegetative propagation (plants), aur sexual reproduction (plants, animals, humans). |
| Aam taur par sirf asexual; process simple aur tez. | Asexual bhi ho sakta hai aur sexual bhi; complex organisms me mostly sexual. |
| Parent apni identity kho deta hai (do daughter cells ban jaata hai). | Parent identity banaye rakhta hai; sirf specific cells/parts reproduction me involve hote hain. |
↔ Table ko side me swipe karein
Q10. How does reproduction help in providing stability to populations of species?
- Kisi bhi population me individuals lagataar marte rehte hain (age, disease, predators). Reproduction unki jagah naye individuals paida karta hai — isliye population size ek stable range me bana rehta hai (birth rate aur death rate ka balance).
- DNA copying kaafi reliable hai, isliye offspring ka body design parent jaisa hi rehta hai — species ki identity aur characteristics generation dar generation maintain rehti hain.
- Saath hi copying me aane wali chhoti variations population ko badalte environment me survive karne layak banati hain — poori population ek saath khatam nahi hoti.
Isliye reproduction ek saath numbers bhi bachaata hai aur species ka design bhi.
Q11. What could be the reasons for adopting contraceptive methods?
- Family size control: bachchon ki sankhya aur do bachchon ke beech ka gap plan karna, taaki har bachche ki achhi parvarish ho sake.
- Maa ki sehat: baar-baar ya bahut jaldi-jaldi pregnancy maa ki health par bura asar daalti hai. Contraception se woh bachaav hota hai.
- STDs se suraksha: barrier method (condom) sexually transmitted diseases — gonorrhoea, syphilis, warts, HIV-AIDS — se bachaata hai.
- Population growth control: tezi se badhti aabaadi resources (food, paani, ghar, jobs) par dabaav daalti hai; contraception se population growth rate control hoti hai aur standard of living better hota hai.
- Unwanted pregnancy se bachaav: jisse hone wale emotional aur social problems se bacha ja sakta hai.
Important Equations — Ek Nazar Me
Asexual reproduction methods — quick reference table
| Method | Example organism | Key feature |
|---|---|---|
| Binary fission | Amoeba, Leishmania, Paramecium, bacteria | Ek parent cell do daughter cells me baantta hai. Amoeba me kisi bhi plane se; Leishmania me whip-like structure ke base se ek definite plane se. |
| Multiple fission | Plasmodium (malarial parasite) | Nucleus baar-baar divide hokar ek saath bahut saare daughter cells banata hai, aksar cyst ke andar — unfavourable conditions survive karne me madad. |
| Fragmentation | Spirogyra | Simple multicellular body tukdon me toot jaati hai; har tukda badhkar naya individual banta hai. |
| Regeneration | Hydra, Planaria | Kate hue tukde se poora organism ban jaata hai. Specialised (undifferentiated) cells proliferate karke saare tissues banate hain. Ye deliberate reproduction nahi, accidental cutting par hota hai. |
| Budding | Hydra, Yeast | Parent body par ek bud nikalti hai, badhti hai aur alag hokar naya individual ban jaati hai. Parent zinda rehta hai. |
| Spore formation | Rhizopus (bread mould) | Hyphae par sporangia (blob-on-a-stick) bante hain jinme spores hote hain. Spores par thick wall — unfavourable conditions me bache rehte hain, hawa se door tak failte hain. |
| Vegetative propagation (natural) | Potato aur ginger (stem), sweet potato aur dahlia (root), Bryophyllum (leaf notches) | Root, stem ya leaf jaise vegetative parts se naya plant. Offspring = parent ka clone; flower/fruit jaldi aate hain. |
| Vegetative propagation (artificial) | Sugarcane, rose, grapes, mango | Cutting, layering, grafting — seed ke bina, desirable variety exactly preserve karke propagate karna. |
| Tissue culture | Ornamental plants (orchids, etc.) | Growing tip ke cells ko nutrient medium me grow karke callus banate hain → hormone medium me plantlets → pot me transfer. Bahut saare identical plants, kam jagah aur kam samay me. |
↔ Table ko side me swipe karein
Ek line ka rule: asexual reproduction me sirf ek parent hota hai, gametes nahi bante, aur offspring genetically parent ke identical clones hote hain — isliye variation na ke barabar.
Common Mistakes — Yahan Marks Kat te Hain
- Budding aur fragmentation ko mila dena. Budding me parent body par ek chhoti nayi outgrowth (bud) ugti hai jo badhkar alag hoti hai — parent poora salaamat rehta hai (Yeast, Hydra). Fragmentation me parent ki apni body hi tukdon me toot jaati hai aur har tukda naya organism banta hai (Spirogyra). Yaad rakho: budding = kuch naya nikla; fragmentation = purana tuta.
- Pollination aur fertilisation ko ek maan lena. Pollination sirf pollen ka anther se stigma tak transfer hai — ye ek physical process hai jisme wind/water/insects ki zaroorat padti hai. Fertilisation male aur female germ cells ka fusion hai jo ovule ke andar hota hai aur zygote banata hai. Pollination pehle, fertilisation baad me. Dono ko interchangeably likhne par pura marks kat jaata hai.
- Ovary aur ovule ka labelling ulta kar dena. Ovary carpel ka phoola hua base hai; ovules ovary ke andar hote hain aur har ovule me ek egg cell hota hai. Fertilisation ke baad: ovule → seed aur ovary → fruit. Students aksar 'ovary → seed' likh dete hain. Diagram me ovary ko cut-open dikhana zaroori hai warna ovules label hi nahi ho paate.
- Binary aur multiple fission ka farak sirf 'do vs bahut' tak seemit rakhna. Answer me ye bhi likho ki multiple fission me nucleus pehle baar-baar divide hota hai phir cytoplasm baantta hai, aur ye aksar cyst ke andar unfavourable conditions me hota hai. Example zaroor do — Amoeba/Leishmania (binary) aur Plasmodium (multiple). Sirf definition likhne par half marks milte hain.
- Vas deferens ko female system me aur fallopian tube ko male system me likh dena. Vas deferens = male (sperms ko testes se urethra tak le jaata hai). Fallopian tube (oviduct) = female (egg ko ovary se uterus tak le jaati hai, aur fertilisation yahin hota hai, uterus me nahi). Ek aur common galti: 'fertilisation uterus me hota hai' — nahi, uterus me sirf implantation aur development hota hai.
- Copper-T ko STD se bachaane wala maan lena, aur 'contraception = sirf pills' samajhna. Copper-T ek IUD hai — sirf pregnancy rokta hai, STDs se koi suraksha nahi deta. Sirf barrier method (condom) hi STDs se bachaata hai, kyunki wahi body fluids ka direct exchange rokta hai. Contraception ke saare chaar types (barrier, hormonal/chemical, IUD, surgical) example ke saath likhna chahiye — vasectomy males me aur tubectomy females me, inko bhi ulta likh dena bahut common galti hai.
Board-Style Important Questions
- 1 mark: Name the part of the flower where the male gametes are produced, and the part where the female gamete is present.
- 1 mark: Which mode of asexual reproduction is shown by Plasmodium, and how is it different from that shown by Amoeba?
- 2 marks: Why is vegetative propagation preferred for plants like banana, orange, rose and jasmine? Give two reasons.
- 3 marks: Explain the structure and function of the placenta in human beings. Why is a large surface area important for it?
- 3 marks: List any three methods of contraception. State which one of them also protects against sexually transmitted diseases, and give a reason.
- 5 marks: Draw a labelled diagram of the longitudinal section of a flower and describe the process of fertilisation in flowering plants. State what happens to the ovule and the ovary after fertilisation.
Quick Quiz — Score Check Karein
Q1. NCERT Class 10 Science Ch.7 ke hisaab se, reproduction ka basic event kya hai?
Q2. Plasmodium (malarial parasite) kis method se asexual reproduction karta hai?
Q3. Rhizopus (bread mould) apne spores kahan banata hai?
Q4. Regeneration se poora naya individual kis organism me ban sakta hai?
Q5. Flower ke kaun se do whorls sexual reproduction me directly involved hote hain?
Q6. Fertilisation ke baad ovary kya banti hai?
Q7. Semen banta hai sperm ke saath kis-kis gland ke secretions milkar?
Q8. Human female menstrual cycle NCERT chapter ke hisaab se lagbhag kitne din ka hota hai, aur bleeding kitne din chalti hai?
Q9. Placenta me embryo ki taraf jo projections hote hain jo absorption ka surface area badhate hain, unhe kya kehte hain?
Q10. Copper-T (IUD) contraception method STDs se suraksha kyun nahi deta?
Aksar Poochhe Jaane Wale Sawaal
Reproduction ko life process kyun kehte hain jab iske bina bhi organism zinda reh sakta hai?
Reproduction individual ke apne survival ke liye zaroori nahi hai — ek organism bina reproduce kiye poori zindagi jee sakta hai. Lekin isse species aage nahi badhegi. Reproduction ko life process isliye maana jaata hai kyunki iske bina koi bhi species kuch hi generations me khatam ho jaayegi. Yaani ye individual level ka nahi, species level ka survival process hai.
Regeneration aur fragmentation me exact farak kya hai?
Fragmentation me organism ki body apne aap tukdon me toot jaati hai aur har tukda naya organism ban jaata hai — ye normal reproduction ka tareeka hai, jaise Spirogyra me. Regeneration me organism kisi accident se kat jaata hai, aur kate hue hisse se specialised cells proliferate karke poora organism bana lete hain — jaise Planaria aur Hydra me. Regeneration reproduction ka regular mode nahi hai, ye ek repair/rebuild capacity hai.
Testes body ke bahar scrotum me kyun hote hain?
Sperm formation ke liye body ke normal temperature se thoda kam temperature chahiye hota hai. Scrotum body cavity ke bahar hone ki wajah se wahan ka temperature body se kuch degree kam rehta hai, jisse sperms theek se ban paate hain aur healthy rehte hain. Agar testes body ke andar hote to sperm production prabhavit hoti.
Fertilisation kahan hota hai — uterus me ya fallopian tube me?
Fertilisation fallopian tube (oviduct) me hota hai. Ovary se release hua egg fallopian tube me aata hai, aur wahin sperm se milta hai. Fertilisation ke baad bana zygote divide hota hua uterus me utarta hai, jahan woh uterus ki thick lining me implant hota hai aur embryo ke roop me develop hota hai. Yaani fertilisation fallopian tube me, development uterus me.
Agar egg fertilise nahi hota to kya hota hai?
Har mahine uterus ki lining fertilised egg ko receive karne ke liye moti aur spongy ho jaati hai aur usme khoob blood supply develop ho jaati hai. Agar egg fertilise nahi hota, to is lining ki zaroorat khatam ho jaati hai aur woh dheere-dheere toot kar blood aur mucous ke roop me vagina se bahar aa jaati hai. Isi ko menstruation kehte hain. Ye cycle lagbhag 28 din ka hota hai.
Sabhi contraceptive methods STDs se kyun nahi bachaate?
STDs — jaise gonorrhoea, syphilis, warts aur HIV-AIDS — sexual contact ke dauran body fluids ke direct exchange se failte hain. Pills hormones badalti hain, Copper-T uterus ke andar kaam karta hai, aur vasectomy/tubectomy gametes ka rasta band karti hain — in me se koi bhi fluids ka contact nahi rokta. Sirf barrier method yaani condom hi physical rukavat banata hai, isliye wahi ek method hai jo pregnancy ke saath-saath STDs se bhi bachaata hai.
Class 10 Science — Saare Chapters
Board exam tak sirf revision karna hai?
Class 10 Science ke saare chapters ke colour handwritten short notes — diagrams, formulas aur important points ek jagah.
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