Class 10 Science · Chapter 6
Short answer:
NCERT Class 10 Science ke Chapter 6 Control and Coordination me total 14 in-text questions (teen page-wise sets — 5 + 5 + 4) aur 12 exercise questions hain. Chapter batata hai ki jeev apne aas-paas ke stimulus ko kaise detect karte hain aur uska response kaise dete hain. Animals me ye kaam do systems milkar karte hain — nervous system (neuron, reflex arc, spinal cord, brain ke teen bhaag: fore-brain, mid-brain, hind-brain) aur endocrine system (hormones jaise thyroxine, insulin, adrenaline, growth hormone, testosterone, oestrogen). Plants me nervous system hota hi nahi, isliye wahan coordination sirf chemical hota hai — immediate movement (touch-me-not ki patti, water ke aane-jaane se) aur growth-dependent movement yaani tropism (phototropism, geotropism, hydrotropism, chemotropism) plus plant hormones (auxin, gibberellin, cytokinin, abscisic acid). Reflex action, reflex arc ka sahi order, aur nervous vs hormonal comparison — ye teen cheezein exam me sabse zyada poochhi jaati hain.
Control and coordination ka matlab hai — body ke alag-alag ang aapas me baat karke ek saath, sahi samay par kaam karein. Aap garam plate ko chhoote ho aur haath apne aap hat jaata hai; ek plant ki tendril support ke around lipat jaati hai — dono hi coordination hai, bas mechanism alag hai. Is chapter me hum dekhenge ki animals me ye kaam electrical impulse (nervous system) aur chemical messenger (hormones) dono se hota hai, jabki plants sirf chemical route pe chalte hain.
Chapter 6 Summary — 5 Minute Revision
1. Stimulus aur Response
- Stimulus = environment ka koi bhi change jise body detect kar sakti hai (light, sound, heat, touch, smell, taste, chemical).
- Response = us stimulus par body ki reaction.
- Living beings apne environment me happening events se apne aap ko protect karne ke liye controlled movement karte hain — aur ye movement growth se jude bhi ho sakte hain aur growth se independent bhi.
2. Nervous System — Neuron
Neuron (nerve cell) nervous system ki structural aur functional unit hai — body ki sabse lambi cell.
- Dendrite — information (impulse) receive karta hai. Yahin dendritic tip par chemical reaction se electrical impulse banta hai.
- Cell body — impulse ko aage bhejta hai.
- Axon — lamba dhaaga jaisa part; impulse ko cell body se axon ke end tak le jaata hai.
- Nerve ending / axon terminal — yahan electrical impulse chemicals release karta hai jo synapse ko paar karte hain.
3. Synapse
Do neurons ke beech ka gap synapse kehlata hai. Ek neuron ka axon-end chemical (neurotransmitter) release karta hai, jo gap paar karke agle neuron ke dendrite me waisa hi naya electrical impulse start kar deta hai. Isi tarah nerve aur muscle cell ke beech bhi similar junction hota hai — wahin se muscle ko action ka signal milta hai. Synapse impulse ko sirf ek direction me jaane deta hai.
4. Reflex Action aur Reflex Arc
Reflex action = kisi stimulus ke prati sudden, automatic, involuntary response — jaise garam cheez chhoote hi haath hatana.
Reflex arc ka order (yaad rakho):
| Step | Kya hota hai |
|---|---|
| 1. Receptor | Skin/organ me stimulus detect hota hai |
| 2. Sensory neuron | Impulse spinal cord tak le jaata hai |
| 3. Relay neuron (spinal cord) | Signal ko sensory se motor neuron tak switch karta hai |
| 4. Motor neuron | Impulse effector tak le jaata hai |
| 5. Effector (muscle/gland) | Response — muscle contract hoti hai |
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Reflex arc spinal cord me hi complete ho jaata hai — brain tak jaane ka intezaar nahi karta, isliye response itna tez hota hai. Brain ko information jaati zaroor hai (isliye aapko dard mehsoos hota hai), par decision spinal cord le chuka hota hai.
5. Human Brain — teen major parts
| Part | Includes | Main functions |
|---|---|---|
| Fore-brain | Cerebrum | Thinking part; hearing, smell, sight, taste ke alag-alag areas; sensory information ka interpretation; voluntary actions ka decision; bhookh ka centre |
| Mid-brain | — | Involuntary actions jaise pupil ka size change hona, sar ka reflex movement |
| Hind-brain | Cerebellum, Pons, Medulla | Cerebellum — posture aur balance, precision of voluntary action; Medulla — blood pressure, salivation, vomiting; Pons — involuntary actions jaise respiration ka regulation |
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6. Protection of nervous tissue
- Brain cranium (skull) me band hota hai, andar cerebrospinal fluid se bhari jhilliyan (membranes) shock absorber ka kaam karti hain.
- Spinal cord vertebral column (backbone) se protected hota hai.
7. Nervous tissue action kaise karwati hai?
Muscle cell me special proteins hote hain jo electrical impulse milne par apna shape aur arrangement badal lete hain — cell chhoti ho jaati hai, yaani muscle contract kar jaati hai. Isi se movement hoti hai.
8. Coordination in Plants — do type ke movements
| Type | Growth se independent | Growth-dependent (Tropic) |
|---|---|---|
| Example | Touch-me-not (Mimosa) ki patti chhoone par band | Tendril ka support ke around lipatna, shoot ka light ki taraf mudna |
| Mechanism | Cells me paani ki matra badalne se shape change — reversible | Ek side par zyada growth — permanent, wapas nahi hota |
| Speed | Fast | Slow |
| Direction | Stimulus ki direction se independent | Stimulus ki direction se decided |
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9. Tropic movements
- Phototropism — light ke response me. Shoot positively phototropic, root negatively phototropic.
- Geotropism — gravity ke response me. Root positively geotropic, shoot negatively geotropic.
- Hydrotropism — paani ke response me. Roots paani ki taraf badhti hain.
- Chemotropism — chemical ke response me. Example: pollen tube ka ovule ki taraf badhna.
Nastic movement (jaise Mimosa ki patti) direction-independent hota hai — isliye wo tropism nahi hai.
10. Plant hormones (phytohormones)
- Auxin — shoot tip me synthesise hota hai; cell elongation karwata hai. Light padne par auxin shade wali side diffuse ho jaata hai, wahan cells zyada lambe hote hain, isliye plant light ki taraf jhuk jaata hai.
- Gibberellin — stem growth me help.
- Cytokinin — cell division promote karta hai; jahan tezi se cell division ho raha ho (fruits, seeds) wahan zyada concentration.
- Abscisic acid (ABA) — growth inhibit karta hai; leaves ka wilting isi ka effect hai.
11. Hormones in Animals — Endocrine system
- Endocrine glands ductless hoti hain — hormone seedha blood me chhodti hain, blood use target organ tak pahunchata hai.
- Hormone bahut kam quantity me chahiye hota hai, par timing aur amount dono precise hone chahiye — isliye feedback mechanism se secretion control hota hai. Example: blood me sugar badhi → pancreas insulin zyada banata hai → sugar normal → insulin secretion kam.
- Iodine thyroxine banane ke liye zaroori hai; kami se goitre ho sakta hai.
- Growth hormone ki kami se dwarfism, zyada hone se gigantism.
12. Nervous vs Hormonal control — quick compare
| Point | Nervous | Hormonal |
|---|---|---|
| Medium | Electrical impulse + chemical at synapse | Chemical (hormone) via blood |
| Speed | Bahut tez | Dheema |
| Reach | Sirf wahan jahan nerve pahunchti hai | Blood ke through poore body me |
| Duration of effect | Short-lived | Lamba chalta hai |
| Response | Point-to-point, localised | Widespread |
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In-Text Questions — Solutions
Q1. What is the difference between a reflex action and walking?
Reflex action ek sudden, automatic aur involuntary response hai jise hum consciously control nahi karte. Iska control spinal cord ke reflex arc se hota hai — signal brain tak jaane ka intezaar nahi karta. Example: pin chubhne par haath jhatak dena.
Walking ek voluntary action hai — ye conscious thinking ke saath hota hai aur iska control fore-brain (cerebrum) karta hai, jabki cerebellum uski precision aur balance sambhalta hai. Aap chalna kab shuru karna hai, kab rukna hai — ye decide kar sakte ho; reflex me ye choice nahi hoti.
Q2. What happens at the synapse between two neurons?
Synapse do neurons ke beech ka chhota sa gap hai. Pehle neuron ke axon terminal par pahunchte hi electrical impulse ek chemical (neurotransmitter) release karwata hai. Ye chemical gap ko paar karke agle neuron ke dendrite par pahunchta hai aur wahan waisa hi naya electrical impulse start kar deta hai.
Iska ek bada fayda ye hai ki impulse sirf ek hi direction me travel karta hai — kyunki chemical sirf axon-end se release hota hai, dendrite se nahi.
Q3. Which part of the brain maintains posture and equilibrium of the body?
Cerebellum — jo hind-brain ka part hai. Yahi body ka posture aur balance (equilibrium) maintain karta hai aur voluntary actions ki precision bhi sambhalta hai. Isiliye cerebellum damage hone par seedha chalna ya cycle chalana mushkil ho jaata hai.
Q4. How do we detect the smell of an agarbatti (incense stick)?
Agarbatti ke chemicals hawa me phailte hain aur naak me maujood olfactory receptors unhe detect karte hain. Ye receptors ek electrical impulse generate karte hain, jo sensory neuron ke through fore-brain ke smell wale area tak jaata hai. Fore-brain us information ko interpret karta hai — tab jaake humein "agarbatti ki khushbu" mehsoos hoti hai.
Q5. What is the role of the brain in reflex action?
Reflex action ka decision brain nahi leta — wo spinal cord ke reflex arc me hi ho jaata hai, isliye response itna tez hota hai. Lekin spinal cord se information brain tak bhi bhej di jaati hai. Brain us information ko interpret karta hai — isi wajah se hume dard ya garmi mehsoos hoti hai, aur hum us situation ko yaad rakhte hain aur aage ke liye soch-samajh kar action le paate hain.
Doosre shabdon me: reflex arc spinal cord me complete hota hai, brain ko sirf information milti hai — bhale hi response ke baad.
Q1. What are plant hormones?
Plant hormones (phytohormones) wo chemical substances hain jo plants me bahut kam maatra me banti hain aur growth, development aur environment ke responses ko control karti hain. Ye plant ke ek hisse me bankar doosre hisson tak diffusion se pahunchti hain (plants me blood jaisa transport system nahi hota).
Main examples: auxin (cell elongation), gibberellin (stem growth), cytokinin (cell division), aur abscisic acid (growth inhibit karta hai).
Q2. How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light?
| Point | Sensitive plant (touch-me-not) ki patti | Shoot ka light ki taraf mudna |
|---|---|---|
| Type | Nastic — growth-independent movement | Tropic (phototropism) — growth-dependent |
| Stimulus | Touch | Light |
| Direction | Stimulus ki direction se koi lena-dena nahi | Stimulus ki direction hi movement ki direction decide karti hai |
| Mechanism | Cells ka paani gain/lose karke shape badalna | Ek side par auxin zyada → wahan zyada cell elongation |
| Speed & nature | Bahut fast, reversible | Slow, permanent |
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Q3. Give an example of a plant hormone that promotes growth.
Auxin — ye shoot tip me banta hai aur cells ki lambai badhakar (cell elongation) growth promote karta hai.
Doosre growth-promoting hormones: gibberellin (stem growth) aur cytokinin (cell division). Growth inhibit karne wala hormone abscisic acid hai — wo is answer me nahi aayega.
Q4. How do auxins promote the growth of a tendril around a support?
Jab tendril kisi support ko chhooti hai, to jo side support se touch me hai wahan ka auxin hatkar doosri (support se door wali) side chala jaata hai. Zyada auxin ka matlab zyada cell elongation — isliye door wali side ke cells tezi se lambe ho jaate hain aur touch wali side ke cells chhote reh jaate hain.
Do sides me growth ka ye antar tendril ko support ki taraf mod deta hai — aur wo dhire-dhire support ke around lipat jaati hai.
Q5. Design an experiment to demonstrate hydrotropism.
Aim: Dikhana ki roots paani ki direction me badhti hain (hydrotropism).
Material: Ek trough/tray, sookhi mitti ya sand, kuchh seeds (jaise moong/gram), ek chhota porous mitti ka bartan (ya beaker) paani ke liye.
Method:
- Trough me sand/soil bhar do aur usme kuchh seeds bo do.
- Seeds ke ek taraf, thoda hatkar paani se bhara porous bartan mitti me gaad do. Baaki mitti ko seedha paani mat do.
- Seeds ko germinate hone do aur kuchh din tak observe karo.
Observation: Shoot upar (gravity ke against) badhta hai, lekin roots seedha neeche na jaakar paani wale bartan ki taraf mudkar badhti hain.
Conclusion: Roots paani ke stimulus ke prati positively respond karti hain — yahi hydrotropism hai.
Q1. How does chemical coordination take place in animals?
Animals me chemical coordination hormones ke through hota hai. Endocrine glands (jo ductless hoti hain) hormone seedha blood me release karti hain. Blood use poore body me le jaata hai, lekin hormone sirf apne target organ/tissue par hi asar karta hai kyunki wahin uske receptors hote hain.
Example: pituitary se growth hormone, thyroid se thyroxine, pancreas se insulin, adrenal gland se adrenaline. Inki quantity feedback mechanism se control hoti hai — jaise blood sugar badhne par pancreas zyada insulin banata hai aur sugar normal hote hi secretion kam kar deta hai.
Q2. Why is the use of iodised salt advisable?
Kyunki iodine thyroid gland ke liye thyroxine hormone banane me zaroori hai. Thyroxine carbohydrate, protein aur fat metabolism ko regulate karta hai.
Agar khane me iodine kam ho to thyroxine kam banega aur thyroid gland badh sakti hai — is condition ko goitre kehte hain (gale ka soojna). Iodised salt use karne se ye deficiency aasani se rok di jaati hai.
Q3. How does our body respond when adrenaline is secreted into the blood?
Adrenaline adrenal glands se seedha blood me chhodta hai aur emergency (dar, gussa, excitement) me body ko action ke liye taiyaar karta hai. Blood use heart aur doosre target organs tak le jaata hai. Iske effects:
- Heartbeat tez ho jaati hai — muscles tak zyada oxygen pahunche.
- Digestive system aur skin ki blood vessels sikud jaati hain, jisse blood ka zyada hissa skeletal muscles ki taraf divert ho jaata hai.
- Diaphragm aur rib muscles ke tez movement se breathing rate badh jaati hai.
Ye sab milkar body ko "fight or flight" ke liye ready kar dete hain.
Q4. Why are some patients of diabetes treated by giving injections of insulin?
Insulin pancreas banata hai aur ye blood me sugar level ko control karta hai. Kuchh diabetes patients me pancreas paryaapt insulin nahi bana pata, isliye blood sugar high rehta hai — jo aage chalkar kai organs ko nuksaan pahunchata hai.
Aise patients ko insulin injection se diya jaata hai. Muh se nahi diya jaata kyunki insulin ek protein hai aur digestive system me digest hokar bekaar ho jaata — injection se wo seedha blood me pahunchkar apna kaam karta 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–Q12)
Q1. Which of the following is a plant hormone? (a) Insulin (b) Thyroxin (c) Oestrogen (d) Cytokinin
(d) Cytokinin
Cytokinin plant hormone hai jo cell division promote karta hai. Insulin (pancreas), thyroxin (thyroid) aur oestrogen (ovary) — teeno animal hormones hain.
Q2. The gap between two neurons is called a (a) dendrite (b) synapse (c) axon (d) impulse
(b) Synapse
Synapse par chemical release hokar gap paar karta hai aur agle neuron me naya impulse start karta hai.
Q3. The brain is responsible for (a) thinking (b) regulating the heart beat (c) balancing the body (d) all of the above
(d) All of the above
Thinking → fore-brain (cerebrum); heart beat aur blood pressure jaisi involuntary cheezein → medulla (hind-brain); balance → cerebellum. Teeno hi brain ke kaam hain.
Q4. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?
Function: Receptors specialised cells/tips hain jo environment se information detect karte hain aur use electrical impulse me convert karke sensory neurons ke through central nervous system tak bhejte hain. Ye zyadatar sense organs me hote hain:
- Photoreceptors — aankh, light
- Phonoreceptors — kaan, sound (aur balance bhi)
- Olfactory receptors — naak, smell
- Gustatory receptors — jeebh, taste
- Thermo/tactile receptors — skin, heat aur touch
Agar receptors theek se kaam na karein: stimulus detect hi nahi hoga, isliye response bhi nahi banega. Body time par khatre se nahi bach payegi — jaise garam cheez chhoone par haath nahi hatega aur jal jaayega, ya kharab khane ki smell/taste pakad me nahi aayegi.
Example situation: Diabetes ke kuchh patients me nerve damage (neuropathy) ke kaaran paon ke receptors kaam karna kam kar dete hain — unhe chot ya jalan pata hi nahi chalti aur ghaav badh jaata hai.
Q5. Draw the structure of a neuron and explain its function.
Structure (label karne wale parts): Dendrite → Cell body (nucleus ke saath) → Axon → Nerve endings / axon terminals. (Diagram me ye chaaron labels zaroor likho — marks inhi par milte hain.)
Function — impulse ka safar:
- Dendritic tip par information receive hoti hai aur ek chemical reaction se electrical impulse banta hai.
- Ye impulse dendrite se cell body tak aata hai.
- Cell body se axon ke through impulse axon ke end tak travel karta hai.
- Axon end par electrical impulse ek chemical release karwata hai, jo synapse ka gap paar karke agle neuron ke dendrite me waisa hi naya impulse shuru kar deta hai.
- Isi tarah impulse aakhir me muscle cell ya gland (effector) tak pahunchkar response karwata hai.
Q6. How does phototropism occur in plants?
Phototropism = light ke response me plant ka growth-dependent movement. Shoot light ki taraf mudta hai (positive phototropism), root light se door (negative phototropism).
Mechanism: Shoot ke tip par auxin banta hai. Jab light ek taraf se aati hai to auxin shoot ke shaded side (jis par light kam pad rahi hai) ki taraf diffuse ho jaata hai. Auxin cell elongation karwata hai, isliye shaded side ke cells zyada lambe ho jaate hain aur light wali side ke cells chhote reh jaate hain.
Do sides ki is unequal growth ki wajah se shoot light ki taraf jhuk jaata hai. Ye movement slow aur permanent hoti hai.
Q7. Which signals will get disrupted in case of a spinal cord injury?
Spinal cord body aur brain ke beech ka main highway hai, aur reflex arcs bhi wahin complete hote hain. Injury hone par:
- Sensory signals — body se brain ki taraf jaane wali information (touch, dard, temperature) disrupt ho jaayegi.
- Motor signals — brain se muscles ki taraf jaane wale instructions disrupt honge, isliye voluntary movement affected hoga.
- Reflex actions — injury wale level se neeche ke reflexes kaam karna band ya kam kar denge, kyunki reflex arc ka relay neuron spinal cord me hi hota hai.
Q8. How does chemical coordination occur in plants?
Plants me na nervous system hota hai, na muscle cells — isliye unka poora coordination chemical hai, yaani plant hormones (phytohormones) ke through.
- Hormone plant ke ek hisse me banta hai aur diffusion se doosre hisson tak pahunchta hai.
- Auxin — cell elongation; phototropism aur tendril ke coiling ke peeche yahi hai.
- Gibberellin — stem ki growth.
- Cytokinin — cell division; fruits aur seeds jaise tezi se divide hone wale areas me zyada.
- Abscisic acid — growth inhibit karta hai; leaves ka wilting iska effect hai.
Iske alawa immediate responses (jaise touch-me-not ki patti) me cells apne andar ka paani ghatakar-badhakar shape badal lete hain — ye bhi chemical/electrochemical signal se hi trigger hota hai.
Q9. What is the need for a system of control and coordination in an organism?
Kisi bhi multicellular organism me alag-alag organs alag-alag kaam karte hain. Agar wo aapas me tal-mel na rakhein to body ek unit ki tarah kaam hi nahi kar payegi. Control and coordination system:
- Environment ke changes (stimuli) ko detect karke sahi aur time par response deta hai — jisse organism khud ko khatre se bacha sake.
- Sabhi organs aur systems ke kaam ko aapas me synchronise karta hai.
- Body ke internal environment ko stable rakhta hai — jaise blood sugar, body temperature, blood pressure (homeostasis).
- Growth, development aur reproduction ko regulate karta hai.
Q10. How are involuntary actions and reflex actions different from each other?
| Point | Involuntary action | Reflex action |
|---|---|---|
| Control centre | Mid-brain aur hind-brain (medulla, pons) | Spinal cord (reflex arc) — brain ke sochne ka intezaar nahi |
| Stimulus | Zaroori nahi ki bahar se koi sudden stimulus ho; ye lagataar chalti rehti hain | Hamesha kisi sudden external stimulus ke response me |
| Nature | Continuous aur regular | Sudden, ek baar ka, bahut tez |
| Examples | Heartbeat, breathing, digestion ka peristalsis, blood pressure ka regulation | Garam cheez chhoote hi haath hatana, pin chubhne par jhatakna, tez light par pupil ka sikudna |
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Note: Dono hi hamare conscious control me nahi hote — farak control centre aur stimulus ke pattern ka hai.
Q11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Similarity: Dono hi body ke alag-alag hisson ko information bhejkar coordination karte hain, aur dono me chemical messengers ka role hai (nervous system me synapse par).
| Point | Nervous mechanism | Hormonal mechanism |
|---|---|---|
| Messenger | Electrical impulse (synapse par chemical) | Hormone (chemical) |
| Transport | Neurons ke through | Blood ke through |
| Speed | Bahut tez | Dheema |
| Reach | Sirf wahin jahan nerve fibre pahunchta hai — point to point | Poore body me, par asar sirf target organ par |
| Duration of effect | Bahut short | Lamba chalta hai |
| Repeat/refresh | Neuron ko agla impulse bhejne se pehle apni cell ko reset karna padta hai | Aisi limitation nahi |
| Control | Brain aur spinal cord | Endocrine glands, feedback mechanism se |
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Q12. What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
| Point | Sensitive plant (touch-me-not) ki patti | Hamare paon ka movement |
|---|---|---|
| Nature | Involuntary — touch ke response me apne aap | Voluntary — hum decide karke karte hain |
| System involved | Koi nervous system nahi, koi muscle tissue nahi | Nervous system + muscles |
| Signal | Cell-to-cell electrochemical signal; koi specialised nerve tissue nahi | Brain se motor neuron ke through electrical impulse |
| Mechanism | Cells apne andar ka paani chhodkar shape aur size badal lete hain, isliye patti mud jaati hai | Muscle cells me special proteins shape/arrangement badalte hain, muscle contract hoti hai |
| Reversal | Paani wapas aane par patti apni normal position me lautti hai | Muscle relax hokar wapas normal ho jaati hai |
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Important Equations — Ek Nazar Me
Animal Hormones — reference table
| Hormone | Gland / Source | Main function | Deficiency / abnormality |
|---|---|---|---|
| Growth hormone | Pituitary gland | Body ki overall growth aur development regulate karta hai | Kami se dwarfism; bachpan me zyada se gigantism |
| Thyroxine | Thyroid gland (iodine zaroori) | Carbohydrate, protein aur fat metabolism ka regulation — balanced growth ke liye | Iodine/thyroxine ki kami se goitre |
| Insulin | Pancreas | Blood me sugar level ko control (kam) karta hai | Kami se blood sugar high — diabetes |
| Adrenaline | Adrenal gland | Emergency hormone — heartbeat aur breathing tez, blood muscles ki taraf divert (fight-or-flight) | — |
| Testosterone | Testes (male) | Male secondary sexual characters — awaaz ka bhaari hona, facial hair | — |
| Oestrogen | Ovary (female) | Female secondary sexual characters — breast development, body shape ke changes | — |
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Plant Hormones — reference table
| Hormone | Where formed / found | Main function | Yaad rakhne wali baat |
|---|---|---|---|
| Auxin | Shoot tip (apex) | Cell elongation — cells lambe hote hain | Phototropism aur tendril ke coiling ke peeche yahi hai |
| Gibberellin | Plant tissues | Stem ki growth me help | Growth promoter |
| Cytokinin | Tezi se cell division wale areas — fruits, seeds | Cell division promote karta hai | Growth promoter |
| Abscisic acid (ABA) | Plant tissues | Growth ko inhibit karta hai | Leaves ka wilting iska effect — ekmatra inhibitor jo NCERT me hai |
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Tropic movements — one-line table
| Movement | Stimulus | Shoot | Root |
|---|---|---|---|
| Phototropism | Light | Positive (light ki taraf) | Negative |
| Geotropism | Gravity | Negative (upar) | Positive (neeche) |
| Hydrotropism | Water | — | Positive (paani ki taraf) |
| Chemotropism | Chemical | Example: pollen tube ka ovule ki taraf badhna | |
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Common Mistakes — Yahan Marks Kat te Hain
- Reflex arc ka order ulta likh dena. Sahi order hai — Receptor → Sensory neuron → Relay neuron (spinal cord) → Motor neuron → Effector (muscle). Bahut students beech me brain ghusa dete hain ya sensory-motor ko swap kar dete hain. Yaad rakho: reflex arc spinal cord me complete hota hai; brain ko information sirf baad me milti hai.
- Tropism ke positive/negative ulte kar dena. Shoot: light ki taraf (positive phototropism) aur gravity ke against (negative geotropism). Root: light se door (negative phototropism) aur gravity ki taraf (positive geotropism), paani ki taraf (positive hydrotropism). Trick — root neeche aur paani ki taraf, shoot upar aur roshni ki taraf.
- Touch-me-not ki patti ko phototropism/tropism keh dena. Wo nastic movement hai — growth-independent, direction-independent, reversible, cells ke paani ghatne-badhne se. Tropism hamesha growth-dependent aur stimulus ki direction se decided hota hai. Exam me ye difference wala question har saal type me aata hai.
- Iodine aur thyroxine ko ek hi cheez samajhna. Iodine ek element hai jo khane se milta hai; thyroxine hormone hai jo thyroid gland iodine ka use karke banati hai. Sahi statement: iodine ki kami → thyroxine kam → goitre. Ye mat likho ki "iodine ki kami se iodine hormone kam ho jaata hai".
- Insulin aur adrenaline ke kaam mila dena. Insulin = pancreas se, blood sugar kam karta hai, deficiency se diabetes. Adrenaline = adrenal gland se, emergency hormone, heartbeat aur breathing tez karta hai. Dono alag glands, alag kaam — ek metabolism ka regulator hai, doosra emergency ka.
- Plant hormone list me abscisic acid ko growth promoter likh dena. Auxin, gibberellin aur cytokinin promote karte hain; abscisic acid akela inhibitor hai (wilting of leaves). Aur "growth promoting plant hormone ka example do" wale question me insulin/thyroxin jaise animal hormone bilkul mat likhna — ye MCQ ka favourite trap hai.
Board-Style Important Questions
- 1 mark: Do neurons ke beech ke gap ko kya kehte hain, aur wahan impulse ek hi direction me kyun travel karta hai?
- 1 mark: Nimn me se plant hormone chuniye — Insulin, Thyroxin, Oestrogen, Cytokinin.
- 2 marks: Phototropism aur geotropism me antar likhiye, ek-ek example ke saath.
- 3 marks: Reflex arc ka labelled path likhiye aur samjhaiye ki reflex action me decision spinal cord kyun leta hai, brain kyun nahi.
- 5 marks: Human brain ke teen major parts ke naam likhiye aur unke functions bataiye. Saath hi bataiye ki brain aur spinal cord ki protection kaise hoti hai.
Quick Quiz — Score Check Karein
Q1. Neuron ka woh part jo stimulus ko receive karke electrical impulse banata hai, wo kaunsa hai?
Q2. Do neurons ke beech ke gap ko kya kehte hain, aur uska kya special property hai?
Q3. Reflex arc ka sahi order kya hai?
Q4. Body ka posture aur balance (equilibrium) maintain karne ka kaam brain ka kaunsa part karta hai?
Q5. Reflex action itna tez kyun hota hai?
Q6. Shoot ka light ki taraf mudna (phototropism) kis mechanism se hota hai?
Q7. Touch-me-not (Mimosa) ki patti ka chhoone par band hona kis type ka movement hai?
Q8. Pollen tube ka ovule ki taraf badhna kis tropism ka example hai?
Q9. Chapter 6 ke intext questions me total kitne questions the aur kaise divide the?
Q10. Nervous aur hormonal control me sabse bada farak kya hai?
Aksar Poochhe Jaane Wale Sawaal
Reflex action aur involuntary action ek hi cheez hai kya?
Nahi. Dono hi hamare conscious control me nahi hote, par reflex action kisi sudden external stimulus ka bahut tez response hai aur spinal cord ke reflex arc se control hota hai. Involuntary action jaise heartbeat aur breathing lagataar chalti rehti hain aur mid-brain/hind-brain (medulla, pons) unhe control karta hai.
Reflex action me brain ka role hai bhi ya nahi?
Decision brain nahi leta — wo spinal cord me hi ho jaata hai, isliye response itna fast hota hai. Lekin spinal cord information brain tak bhejta zaroor hai. Isi wajah se aapko dard mehsoos hota hai aur aap us experience ko yaad rakhte ho.
Plants me nervous system nahi hai to wo stimulus ka response kaise dete hain?
Plants electrochemical signals aur chemical hormones ka use karte hain. Fast response me cells apne andar ka paani ghatakar-badhakar shape badal lete hain, jaise touch-me-not ki patti. Slow response growth-dependent hota hai, jaise auxin ki wajah se shoot ka light ki taraf mudna.
Auxin exactly karta kya hai?
Auxin shoot tip me banta hai aur cells ki lambai badhata hai yaani cell elongation karwata hai. Jab light ek taraf se aati hai to auxin shade wali side chala jaata hai, wahan cells zyada lambe ho jaate hain, aur plant light ki taraf jhuk jaata hai. Tendril ke coiling me bhi yahi mechanism hai.
Insulin ko goli ki jagah injection se kyun dete hain?
Insulin ek protein hai. Agar muh se liya jaaye to digestive system usse digest kar dega aur wo kaam ka nahi rahega. Injection se wo seedha blood me pahunch jaata hai aur blood sugar ko control kar pata hai.
Sirf iodised namak khaane se goitre sach me ruk jaata hai?
Thyroid gland ko thyroxine banane ke liye iodine chahiye. Khane me iodine ki kami se thyroxine kam banta hai aur gland badh sakti hai, jise goitre kehte hain. Iodised salt is deficiency ko rokne ka sabse aasan tareeka hai, isiliye NCERT bhi iski salah deta 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.
NCERT Kaksha ek swatantra shaikshik platform hai aur NCERT ya CBSE se aadhikarik roop se sambaddh (officially affiliated) nahi hai. Kisi galti ki jaankari dene ke liye contact kijiye.