Class 10 Science

Chapter 5: Life Processes

An in-depth, visual, and interactive guide to the essential maintenance functions that keep living organisms alive.

🌐 Language / भाषा:

Remember from before:

In Class 9, we learned that the cell is the basic structural and functional unit of life. Class 9 में, हमने सीखा था कि cell ही life की basic structural और functional unit है।
We saw that multi-cellular organisms have specialized tissues to perform specific body functions. हमने देखा कि multi-cellular organisms के पास specific body functions perform करने के लिए specialized tissues होते हैं।
Maintenance of living structures is necessary because they tend to break down over time due to environmental interactions. Living structures का maintenance बहुत जरूरी है क्योंकि environmental interactions के कारण वे समय के साथ break down हो सकते हैं।

1. What are Life Processes? 1. Life Processes (जैव प्रक्रम) क्या हैं?

Section Goal: Define what a life process is and understand why simple diffusion is not enough to keep large multi-cellular organisms alive. Section Goal: Life process क्या है, इसे समझें और जानें कि बड़े multi-cellular organisms को alive रखने के लिए simple diffusion (विसरण) क्यों काफी नहीं है।

💡 The Building Maintenance Analogy: Imagine a large school building. Even when classes are not running or students are asleep, a team of sweepers, security guards, and repair staff must continuously work to keep the walls clean, fix broken pipes, and protect the structure. If they stop, the building will slowly crumble. Life processes are like this school maintenance team. 💡 The Building Maintenance Analogy: एक बड़े school building की कल्पना करें। जब classes नहीं चल रही हों या students सो रहे हों, तब भी sweepers, security guards, और repair staff की team को building को साफ़ और safe रखने के लिए continuous काम करना पड़ता है। अगर वे रुक गए, तो building धीरे-धीरे खराब हो जाएगी। Life processes भी हमारी body की इसी maintenance team की तरह हैं।

How do we tell the difference between what is alive and what is not alive? Visible movements like a dog running, a cow chewing cud, or a plant growing are obvious signs of life. However, a plant that is not visibly growing is still alive, and an animal can breathe without visible body movement. Therefore, invisible molecular movements are the real defining characteristics of life [NCERT p.79]. हम कैसे decide करते हैं कि कोई चीज़ alive (सजीव) है या not alive (निर्जीव)? किसी dog का दौड़ना, cow का जुगाली करना, या plant का grow करना, ये सब life के visible movements (दिखने वाले लक्षण) हैं। लेकिन, जो plant visibly grow नहीं कर रहा है, वह भी alive है, और एक animal बिना किसी visible movement के भी breathe कर सकता है। इसलिए, invisible molecular movements (अदृश्य आणविक गतियाँ) ही life की real defining characteristics हैं [NCERT p.79]।

Living organisms are made of highly organized structures (cells and tissues). These structures tend to break down over time. To prevent this breakdown, organisms need continuous repair and maintenance. The processes which together perform this maintenance job of living organisms are called life processes [NCERT p.80]. Living organisms एक highly organized structures (cells और tissues) के बने होते हैं। ये structures समय के साथ break down हो सकते हैं। इस breakdown को रोकने के लिए, organisms को continuous repair and maintenance (मरम्मत और अनुरक्षण) की जरूरत होती है। वे सभी processes जो मिलकर living organisms के maintenance का काम करती हैं, उन्हें life processes (जैव प्रक्रम) कहते हैं [NCERT p.80]।

Because maintenance requires energy, organisms must take in food from the outside. This is done through the process of nutrition (पोषण). This food is then broken down inside the body by chemical reactions (often using oxygen) to release energy. This process of using oxygen to break down food for cellular needs is called respiration (श्वสน) [NCERT p.80]. चूंकि maintenance के लिए energy की जरूरत होती है, इसलिए organisms को outside से food लेना पड़ता है। यह process nutrition (पोषण) कहलाती है। इस food को body के अंदर chemical reactions के द्वारा break down किया जाता है (often oxygen का use करके) ताकि energy release हो सके। Cellular needs के लिए food के breakdown में oxygen का use करने की process को respiration (श्वसन) कहते हैं [NCERT p.80]।

🧠 Checkpoint Question

Why is simple diffusion (विसरण) insufficient to meet the oxygen requirements of multi-cellular organisms like humans? Humans जैसे multi-cellular organisms की oxygen requirements को पूरा करने के लिए simple diffusion (विसरण) क्यों काफी नहीं है?

Correct! In single-celled organisms, the entire surface is in contact with the environment, so simple diffusion is enough. But in large multi-cellular organisms, the body volume is huge, and direct environment contact is limited. For example, it is calculated that if diffusion alone were to transport oxygen in humans, it would take 3 years for an oxygen molecule to reach our toes from our lungs! [NCERT p.90]

Section Summary:

Molecular movements, though invisible, are the fundamental proof of life. Invisible molecular movements ही life का fundamental validation (प्रमाण) हैं।
Life processes include Nutrition, Respiration, Transportation, and Excretion, which cooperate to maintain the living state. Nutrition, Respiration, Transportation, और Excretion ही main life processes हैं जो body को sustain करने में help करती हैं।
Multi-cellular complexity prevents simple diffusion from distributing nutrients and oxygen to all cells, requiring specialized systems. Multi-cellular body structure की complexity के कारण simple diffusion oxygen और nutrients को सभी cells तक नहीं पहुँचा सकता, इसके लिए complex organs की जरूरत होती है।

2. Nutrition 2. Nutrition (पोषण)

Section Goal: Contrast autotrophic and heterotrophic nutrition, explain the biochemical steps of photosynthesis, and detail human digestion. Section Goal: Autotrophic और heterotrophic nutrition के बीच का contrast समझें, photosynthesis के steps और human digestion system की functioning को detail में समझें।

💡 The Fuel Analogy: A car needs petrol to run. Similarly, our body needs food as fuel to perform work, grow, and build new tissues. Autotrophs are like solar-powered electric cars (making their own fuel from sunlight), while heterotrophs are like traditional cars that must pull up to a petrol pump (consume other organisms) to get fuel. 💡 The Fuel Analogy: एक car को चलने के लिए petrol की जरूरत होती है। वैसे ही, हमारी body को growth और tissue repair के लिए food की जरूरत होती है। Autotrophs solar-powered cars की तरह हैं (जो sunlight से अपना fuel खुद बनाते हैं), जबकि heterotrophs traditional cars की तरह हैं जिन्हें fuel के लिए petrol pump पर जाना पड़ता है (दूसरे organisms को consume करना पड़ता है)।

Modes of Nutrition Modes of Nutrition (पोषण के प्रकार)

Nutrition Nutrition (पोषण)

→

Autotrophic
(Green Plants) Autotrophic (स्वपोषी - हरे पौधे)

→

Heterotrophic Heterotrophic (विषमपोषी)

→

Holozoic (Humans, Amoeba) Holozoic (मानव, अमीबा) Saprophytic (Yeast, Fungi) Saprophytic (मृतजीवी - यीस्ट, कवक) Parasitic (Cuscuta) Parasitic (परजीवी - अमरबेल)

Autotrophic Nutrition Autotrophic Nutrition (स्वपोषी पोषण)

Organisms that manufacture their own organic food from simple inorganic materials (like carbon dioxide and water) using sunlight are called autotrophs. This category includes green plants and some bacteria [NCERT p.81]. वे organisms जो simple inorganic materials (जैसे carbon dioxide और water) से sunlight और chlorophyll का use करके अपना food खुद बनाते हैं, उन्हें autotrophs कहते हैं। इस category में green plants और कुछ bacteria आते हैं [NCERT p.81]।

The carbon and energy requirements of the autotrophic organism are fulfilled by photosynthesis (प्रकाश-संश्लेषण). It is the process by which autotrophs take in substances from the outside and convert them into stored forms of energy. The raw materials used are carbon dioxide ($CO_2$) and water ($H_2O$), which are converted into carbohydrates (glucose) in the presence of sunlight and chlorophyll [NCERT p.81]. Autotrophic organisms की carbon और energy requirements photosynthesis (प्रकाश-संश्लेषण) के द्वारा पूरी होती हैं। यह वह process है जिसके द्वारा autotrophs बाहर से substances लेकर उन्हें stored energy form में convert करते हैं। Raw materials के रूप में carbon dioxide ($CO_2$) और water ($H_2O$) का use किया जाता है, जो sunlight और chlorophyll की presence में carbohydrates (glucose) में convert हो जाते हैं [NCERT p.81]।

                    6CO₂ + 12H₂O —(Sunlight / Chlorophyll)→ C₆H₁₂O₆ + 6O₂ + 6H₂O
                

The process of photosynthesis occurs in three distinct steps [NCERT p.81]: Photosynthesis की process तीन distinct steps में पूरी होती है [NCERT p.81]:

Absorption of light energy by chlorophyll. Chlorophyll द्वारा light energy का absorption (अवशोषण) करना।
Conversion of light energy to chemical energy and splitting of water ($H_2O$) molecules into hydrogen and oxygen. Light energy का chemical energy में conversion (परिवर्तन) और water ($H_2O$) molecules का hydrogen और oxygen में splitting (विखंडन) होना।
Reduction of carbon dioxide ($CO_2$) to carbohydrates (glucose). Carbon dioxide ($CO_2$) का carbohydrates (glucose) में reduction (अपचयन) होना।

Source: NCERT Science (Class 10), Chapter 5, Fig 5.1 (Cross-section of a leaf), p. 82.

If you carefully observe a cross-section of a leaf under a microscope, you will notice that some cells contain green dots. These green dots are cell organelles called chloroplasts (हरितलवक) which contain the green pigment chlorophyll [NCERT p.82]. अगर आप microscope के अंदर leaf के cross-section को observe करेंगे, तो आपको cells में कुछ green dots दिखेंगे। ये green dots cell organelles हैं जिन्हें chloroplasts (हरितलवक) कहते हैं, और इनके अंदर green pigment chlorophyll होता है [NCERT p.82]।

Source: Adapted from NCERT Science (Class 10), Chapter 5, Chloroplast organelle structure, p. 82.

Stomata: The Gas Gates Stomata: The Gas Gates (रंध्र)

Photosynthesis requires carbon dioxide. Gas exchange is facilitated by tiny pores on the leaf surface called stomata (रंध्र) [NCERT p.83]. Photosynthesis के लिए carbon dioxide जरूरी है। Gas exchange leaf की surface पर present tiny pores के द्वारा होता है जिन्हें stomata (रंध्र) कहते हैं [NCERT p.83]।

Opening and closing of stomatal pores is controlled by guard cells (द्वार कोशिकाएँ). When water flows into the guard cells, they swell (become turgid) and curve outwards, opening the pore. When guard cells lose water, they shrink (become flaccid) and straighten, closing the pore to prevent water loss when gas exchange is not needed [NCERT p.83]. Stomatal pores का open और close होना guard cells (द्वार कोशिकाएँ) control करती हैं। जब water guard cells के अंदर जाता है, तो वे swell (turgid) हो जाती हैं और curve होकर pore को open कर देती हैं। जब guard cells water lose करती हैं, तो वे shrink (flaccid) हो जाती हैं और pore close हो जाता है ताकि moisture loss न हो [NCERT p.83]।

Source: NCERT Science (Class 10), Chapter 5, Fig 5.2 (Open and Closed Stomatal Pore), p. 83.

Heterotrophic Nutrition Heterotrophic Nutrition (विषमपोषी पोषण)

Organisms that cannot prepare their own food and must depend on other organic sources are called heterotrophs. This includes animals, fungi, and non-green plants [NCERT p.84]. वे organisms जो अपना food खुद prepare नहीं कर सकते और दूसरे organic sources पर depend होते हैं, उन्हें heterotrophs कहते हैं। इसमें animals, fungi, और non-green plants शामिल हैं [NCERT p.84]।

Source: NCERT Science (Class 10), Chapter 5, Fig 5.3 (Nutrition in Amoeba), p. 85.

Human Digestive System Human Digestive System (मानव पाचन तंत्र)

The human alimentary canal (आहार नाल) is a continuous muscular tube extending from the mouth to the anus, specialized in different regions to digest and absorb nutrients [NCERT p.85]. Human alimentary canal (आहार नाल) mouth से लेकर anus तक एक continuous muscular tube है, जो अलग-अलग regions में nutrients को digest और absorb करने के लिए specialized है [NCERT p.85]।

Source: NCERT Science (Class 10), Chapter 5, Fig 5.6 (Human alimentary canal), p. 85.

Summary of Human Digestive Enzymes Summary of Human Digestive Enzymes (पाचन एंजाइमों का सारांश)

The complete digestion of food is carried out by various enzymes secreted along the alimentary canal [NCERT pp.85-86]:

Organ (अंग) Organ (अंग)	Secretion / Enzyme (स्राव / एंजाइम) Secretion / Enzyme (स्राव / एंजाइम)	Function / Biological Process (कार्य) Function / Biological Process (कार्य)
Mouth (मुख) Mouth (मुख)	Salivary Amylase (लार एमाइलेज) Salivary Amylase (लार एमाइलेज)	Breaks down complex starch into simple sugar (maltose). Saliva wets food for swallowing [NCERT p.85]. Complex starch को simple sugar (maltose) में तोड़ता है। Saliva food को wet करता है ताकि swallow करना आसान हो सके [NCERT p.85]।
Stomach (अमाशय) Stomach (अमाशय)	Gastric juice (HCl, Pepsin, Mucus) Gastric juice (HCl, Pepsin, Mucus)	HCl creates an acidic medium; Pepsin digests proteins; Mucus protects stomach lining from acid corrosion [NCERT p.86]. HCl acidic medium बनाता है; Pepsin proteins digest करता है; Mucus stomach lining को acid corrosion से बचाता है [NCERT p.86]।
Small Intestine (क्षुद्रांत्र) Small Intestine (क्षुद्रांत्र)	Bile (from Liver), Trypsin & Lipase (from Pancreas) Bile (Liver से), Trypsin & Lipase (Pancreas से)	Bile emulsifies fats; Trypsin digests proteins into amino acids; Lipase breaks down fats into fatty acids & glycerol [NCERT p.86]. Bile fats को emulsify करता है; Trypsin proteins को amino acids में बदलता है; Lipase fats को fatty acids और glycerol में तोड़ता है [NCERT p.86]।
Villi (दीर्घरोम) Villi (दीर्घरोम)	Intestinal capillary network Intestinal capillary network	Vastly increases internal surface area of the small intestine to absorb digested food into blood capillaries [NCERT p.86]. Digested food के absorption के लिए small intestine का surface area बढ़ाते हैं ताकि capillaries absorb कर सकें [NCERT p.86]।

Intestinal Absorption and Villi Intestinal Absorption and Villi (दीर्घरोम और अवशोषण)

The inner lining of the small intestine contains millions of tiny, finger-like projections called villi (दीर्घरोम) [NCERT p.86]. Small intestine की inner lining पर millions of finger-like projections होते हैं जिन्हें villi (दीर्घरोम) कहते हैं [NCERT p.86]।

Surface Area: Villi vastly increase the surface area available for the absorption of digested food molecules. Surface Area: Villi absorption के लिए small intestine के surface area को vastly increase कर देते हैं।
Blood Supply: Villi are richly supplied with blood vessels (capillaries) that carry the absorbed nutrients to each and every cell of the body for energy, growth, and tissue repair [NCERT p.86]. Blood Supply: Villi में rich blood capillary network होता है, जो absorbed nutrients को body की हर cell तक energy, growth, और tissue repair के लिए ले जाता है [NCERT p.86]।

Source: Adapted from NCERT Science (Class 10), Chapter 5, Villi micro-absorption system, p. 86.

🧠 Checkpoint Question

What would happen if the gastric glands in the stomach stopped secreting hydrochloric acid ($HCl$)? अगर stomach की gastric glands hydrochloric acid ($HCl$) secrete करना बंद कर दें, तो क्या होगा?

Correct! Pepsin is a proteolytic enzyme that requires an acidic medium (created by $HCl$) to activate from its precursor form, pepsinogen. If $HCl$ is absent, pepsin cannot function, and protein breakdown will fail. Additionally, $HCl$ kills harmful bacteria ingested with food. [NCERT p.86]

Section Summary:

Photosynthesis converts $CO_2$ and $H_2O$ to glucose using solar energy trapped by chlorophyll. Photosynthesis green plants में carbon dioxide और water को glucose में convert करता है using chlorophyll और sunlight.
Stomatal opening is regulated by turgor pressure changes in guard cells. Stomatal opening guard cells के turgor pressure के changes के द्वारा control होती है।
Human digestion is extracellular; complex foods are hydrolyzed by salivary, gastric, pancreatic, and intestinal enzymes. Human digestion extracellular है, जिसमें enzymes (salivary, gastric, pancreatic) polymers को soluble monomers में hydrolyze करते हैं।

3. Respiration 3. Respiration (श्वसन)

Section Goal: Differentiate aerobic and anaerobic respiration and explain the cellular breakdown of glucose under different oxygen conditions. Section Goal: Aerobic और anaerobic respiration के बीच का difference समझें और जानें कि अलग-अलग oxygen conditions में glucose का breakdown कैसे होता है।

💡 The Power Grid Analogy: Glucose is like raw coal brought to a power plant. The power plant (cell) breaks this coal down to produce electricity (ATP molecules). Respiration is the process of burning that coal. If oxygen is available, the combustion is clean and yields high power (38 ATP). If oxygen is absent, it is like smoldering, producing low energy and soot/byproducts (like lactic acid or ethanol). 💡 The Power Grid Analogy: Glucose एक raw coal (कच्चा कोयला) की तरह है जो power plant (cell) में आता है। Power plant इस coal को burn करके electricity (ATP molecules) generate करता है। Respiration coal burning की process है। Agar oxygen available है, तो combustion clean होगा और high power (36-38 ATP) मिलेगी। Agar oxygen absent है, तो low energy के साथ ethanol या lactic acid जैसे byproducts बनते हैं।

The food material taken in during nutrition is used in cells to provide energy for various life activities. Living organisms use different pathways to release this energy. Some use oxygen to break down glucose completely, while others do not require oxygen [NCERT p.87]. Nutrition के दौरान जो food material लिया जाता है, उसका use cells energy release करने के लिए करती हैं। Living organisms इस energy को release करने के लिए अलग-अलग pathways use करते हैं। कुछ organisms oxygen का use करके glucose को complete break down करते हैं, जबकि कुछ बिना oxygen के काम चलाते हैं [NCERT p.87]।

Paths of Glucose Breakdown Paths of Glucose Breakdown (ग्लूकोज विखंडन के पथ)

Breakdown of Glucose by Various Pathways

Glucose (6-Carbon) —[In Cytoplasm]→ Pyruvate (3-Carbon) + Energy

Absence of O₂
(in Yeast)
↓
Ethanol (2C) + CO₂ + 2 ATP

Lack of O₂
(in muscle cells)
↓
Lactic Acid (3C) + 2 ATP

Presence of O₂
(in Mitochondria)
↓
CO₂ + H₂O + 36-38 ATP

Human Respiratory System Human Respiratory System (मानव श्वसन तंत्र)

In human beings, air is taken in through the nostrils. The air passing through the nostrils is filtered by fine hairs and mucus. The air then passes through the throat (pharynx, larynx) and into the trachea. The trachea has rings of cartilage (उपास्थि वलय) which ensure that the air-passage does not collapse when there is no air in it [NCERT pp.89-90]. Humans में air nostrils (नासाद्वार) के रास्ते body में enter करती है। Nostrils से pass होने वाली air fine hairs और mucus के द्वारा filter होती है। फिर air throat (pharynx, larynx) से होते हुए trachea (श्वासनली) में जाती है। Trachea में rings of cartilage (उपास्थि वलय) होते हैं जो ensure करते हैं कि air passage collapse न हो जब उसमें हवा न हो [NCERT pp.89-90]।

Pathway of Air during Respiration (श्वसन मार्ग)

Nostrils
(नासाद्वार)

→

Nasal Passage
(नासा मार्ग)

→

Pharynx
(ग्रसनी)

→

Larynx
(कंठ)

→

Trachea
(श्वासनली)

→

Bronchi
(श्वसनी)

→

Bronchioles
(श्वसनिकाएँ)

→

Alveoli
(कूपिकाएँ - Gas Exchange)

→

Blood Capillaries
(रुधिर वाहिकाएँ)

3D Human Respiratory System Anatomy Layout

Source: NCERT Science (Class 10), Chapter 5, Fig 5.8 (Human respiratory system), p. 90.

🧠 Checkpoint Question

Why does the rate of breathing in aquatic organisms (like fish) tend to be much faster than that of terrestrial organisms (like humans)? Aquatic organisms (जैसे fish) का breathing rate terrestrial organisms (जैसे humans) के breathing rate से बहुत तेज़ क्यों होता है?

Correct! Since the concentration of dissolved oxygen in water is much lower than the concentration of oxygen in the air, aquatic organisms must breathe rapidly to extract enough oxygen from water to meet their metabolic demands. [NCERT p.89]

Section Summary:

The breakdown of glucose begins in the cytoplasm to form pyruvate, which undergoes different fates depending on oxygen availability. Glucose का breakdown cytoplasm में pyruvate बनने से start होता है, जो oxygen की availability के basis पर अलग paths follow करता है।
Aerobic respiration in mitochondria yields much more energy (36-38 ATP) than anaerobic fermentation in yeast (2 ATP). Mitochondria में aerobic respiration से बहुत ज़्यादा energy (36-38 ATP) release होती है compared to yeast fermentation (2 ATP)।
Alveoli in human lungs provide a large, highly capillary-rich surface area for gas exchange, aided by the pigment hemoglobin. Lungs में alveoli (कूपिकाएँ) gas exchange के लिए blood capillaries से घिरा एक बहुत बड़ा surface area बनाती हैं, जिसमें oxygen transport helper hemoglobin होता है।

4. Transportation 4. Transportation (वहन)

Section Goal: Explain double circulation in the human heart and contrast the transport of water (Xylem) and food (Phloem) in plants. Section Goal: Double circulation क्या है, इसे human heart के loop से समझें, और plants में water (xylem) और food (phloem) के transport के mechanisms के बीच difference समझें।

💡 The Highway and Delivery Truck Analogy: Blood vessels are like one-way delivery highways. Oxygen and nutrients are goods loaded onto delivery trucks (blood cells). In humans, the heart acts as a central sorting hub with two loops: one loop goes to the factory (lungs) to load oxygen, and the other loop distributes it to the cities (body tissues). In plants, xylem is like a one-way pipeline carrying water up from the ground, while phloem is a two-way courier service distributing food from leaves to all branches. 💡 The Highway and Delivery Truck Analogy: Blood vessels एक one-way delivery highways की तरह हैं। Oxygen और nutrients, trucks (blood cells) पर loaded goods हैं। Humans में, heart central sorting hub की तरह काम करता है जिसमें दो loops हैं: एक loop factory (lungs) जाता है oxygen भरने के लिए, और दूसरा loop उसे cities (body tissues) में distribute करता है। Plants में, xylem roots से ऊपर पानी ले जाने वाली pipeline है, और phloem leaves से food deliver करने वाली courier service है।

Human Circulatory System Human Circulatory System (मानव परिसंचरण तंत्र)

Humans have a muscular pumping organ called the heart (हृदय) that keeps blood in continuous circulation. Our blood transports oxygen, carbon dioxide, food, water, and nitrogenous waste materials [NCERT p.90]. Humans के पास एक muscular pumping organ होता है जिसे heart (हृदय) कहते हैं, जो blood को circulatory system में pumping के ज़रिये move करता है। हमारा blood oxygen, carbon dioxide, digested food, water, और nitrogenous waste materials को transport करता है [NCERT p.90]।

Schematic Circuit of Double Circulation

Lungs (Oxygenation)

→

Left Atrium & Ventricle

→

Aorta & Body Tissues

→

Right Atrium & Ventricle

→

Pulmonary Artery

Source: NCERT Science (Class 10), Chapter 5, Fig 5.10 (Sectional view of human heart), p. 92.

Transportation in Plants Transportation in Plants (पादपों में परिवहन)

Plants are stationary and have low energy needs. They transport substances through two separate conducting tissues [NCERT p.95]:

Xylem (जाइलम): Transports water and minerals absorbed from the soil upwards. Xylem transport is driven by:
- Root Pressure (मूल दाब): Active transport of ions at root cells creates a concentration gradient, pushing water up from the base. This is effective mainly at night [NCERT p.95].
- Transpiration Pull (वाष्पोत्सर्जन खिंचाव): Evaporation of water from stomatal pores creates a suction force that pulls water columns up through the xylem vessels. This is the major driving force during the day [NCERT p.96].
Phloem (फ्लोएम): Transports products of photosynthesis (sucrose, amino acids) from leaves to other parts of the plant. This is called translocation (स्थानांतरण). Unlike xylem, translocation in phloem requires energy from ATP to build osmotic pressure, moving food to low-pressure areas [NCERT p.96].

Plant Transport System (पादपों में परिवहन)

XYLEM (जाइलम)

Transports water & minerals upwards from soil [NCERT p.95].
One-way flow (unidirectional).
Uses physical forces: Root Pressure (night) & Transpiration Pull (day) [NCERT p.96].
Passive transport; no cellular energy (ATP) used.

PHLOEM (फ्लोएम)

Transports food & amino acids (translocation) from leaves to organs [NCERT p.96].
Two-way flow (bidirectional).
Uses osmotic pressure created by active loading [NCERT p.96].
Active transport; requires ATP energy [NCERT p.96].

🧠 Checkpoint Question

Why is blood circulation in birds and mammals called "Double Circulation", and why is it important? Birds और mammals में blood circulation को "Double Circulation" (दोहरा परिसंचरण) क्यों कहते हैं, और यह क्यों ज़रूरी है?

Correct! Warm-blooded animals (birds and mammals) have high energy needs to maintain their body temperature. Double circulation completely separates oxygenated blood from deoxygenated blood, ensuring an efficient, highly concentrated supply of oxygen to all body tissues. [NCERT p.92]

Section Summary:

The human heart has 4 chambers to separate oxygenated and deoxygenated blood flow. Human heart के पास 4 chambers होते हैं ताकि deoxygenated और oxygenated blood mix न हो सकें।
Double circulation consists of the pulmonary circuit (to lungs) and the systemic circuit (to body). Double circulation में pulmonary circuit (lungs तक) और systemic circuit (body tissues तक) शामिल होते हैं।
Xylem relies on physical forces (root pressure, transpiration suction) to lift water, while phloem translocation is active and uses ATP. Xylem water lift करने के लिए physical forces (transpiration suction pull) पर depend करता है, जबकि phloem translocation active process है जिसमें ATP use होती है।

5. Excretion 5. Excretion (उत्सर्जन)

Section Goal: Explain the parts of the human excretory system, how nephrons filter blood, and the excretion mechanisms in plants. Section Goal: Human excretory system के अलग-अलग parts को समझें, जानें कि nephrons blood filtration कैसे करते हैं और plants के excretion methods क्या हैं।

💡 The Kitchen Cleaning Analogy: Imagine a busy restaurant kitchen. Over the day, organic garbage, dirty water, and plastic wrappers accumulate. If you don't throw them out, the kitchen will start smelling and become toxic. In our body, metabolism creates nitrogenous waste (urea). Excretion is like the kitchen cleaning and trash disposal crew, with kidneys acting as high-tech filters that separate trash from useful water. 💡 The Kitchen Cleaning Analogy: एक busy restaurant kitchen की कल्पना करें। दिन भर में वहाँ कचरा, गंदा पानी, और wrappers जमा हो जाते हैं। अगर उन्हें फेंका न जाए, तो kitchen toxic हो जाएगा। हमारी body में भी metabolism nitrogenous waste (urea) generate करता है। Excretion body की उसी cleaning crew की तरह है, जिसमें kidneys high-tech filters की तरह useful water से कचरे को separate करती हैं।

Metabolic activities in organisms generate nitrogenous waste products (like urea or uric acid) that are toxic and must be removed. The biological process involved in the removal of these harmful metabolic wastes is called excretion [NCERT p.96].

Excretion in Human Beings Excretion in Human Beings (मानव उत्सर्जन तंत्र)

3D Human Excretory System Anatomy Layout

Source: NCERT Science (Class 10), Chapter 5, Fig 5.13 (Human excretory system), p. 96.

Pathway of Urine Flow (मूत्र का मार्ग)

Kidneys
(वृक्क - filter blood & produce urine)

→

Ureters
(मूत्रवाहिनी - conduct urine down)

→

Urinary Bladder
(मूत्राशय - temporarily stores urine)

→

Urethra
(मूत्रमार्ग - excretes urine out)

Excretion in Plants Excretion in Plants (पादपों में उत्सर्जन)

Each kidney contains a large number of basic filtration units called nephrons (वृक्काणु) packed close together. A nephron functions in three steps [NCERT p.97]:

Steps in Urine Formation inside a Nephron

Ultrafiltration
(Bowman's Capsule)

→

Selective Reabsorption
(PCT & loop of Henle)

→

Urine Secretion
(Collecting Duct)

Source: NCERT Science (Class 10), Chapter 5, Fig 5.14 (Structure of nephron), p. 97.

Excretion in Plants (पादपों में उत्सर्जन)

Plants use completely different strategies for excretion [NCERT p.98]: Plants excretion के लिए completely different techniques का use करते हैं [NCERT p.98]:

Oxygen ($O_2$) and carbon dioxide ($CO_2$) are expelled as gaseous wastes through stomatal pores [NCERT p.98]. Oxygen ($O_2$) और carbon dioxide ($CO_2$) को gaseous waste की तरह stomatal pores के रास्ते expel किया जाता है [NCERT p.98]।
Excess water is lost by transpiration [NCERT p.98]. Excess water transpiration (वाष्पोत्सर्जन) के द्वारा lost होता है [NCERT p.98]।
Many plant wastes are stored in cellular vacuoles or in dead cells, and are removed when leaves die and fall off [NCERT p.98]. बहुत से plant wastes vacuoles और dead cells में store होते हैं, जो leaves के टूटकर गिरने के साथ ही remove हो जाते हैं [NCERT p.98]।
Wastes are also stored as resins (राल) and gums (गोंद), especially in old xylem vessels [NCERT p.98]. Wastes को old xylem vessels में resins (राल) और gums (गोंद) के रूप में भी store किया जाता है [NCERT p.98]।
Plants also excrete some waste substances into the soil around them [NCERT p.98]. Plants surrounding soil में भी कुछ waste products excrete करते हैं [NCERT p.98]।

🧠 Checkpoint Question

What is the function of the glomerulus in the nephron? Nephron में glomerulus का क्या काम होता है?

Correct! The glomerulus acts as a sieve/filter. Blood flows through it under high pressure, forcing water, glucose, amino acids, salts, and nitrogenous wastes into the Bowman's capsule, while larger blood cells and proteins remain in the blood. [NCERT p.97]

Section Summary:

The human excretory system consists of kidneys, ureters, urinary bladder, and urethra. Human excretory system में kidneys, ureters, urinary bladder, और urethra शामिल होते हैं।
Kidney filtration is carried out by nephrons via glomerular filtration, tubular reabsorption, and urine concentration. Kidneys में filtration nephrons के द्वारा होता है जिसमें glomerular filtration, selective tubular reabsorption, और urine concentration शामिल हैं।
Plants excrete gaseous wastes through stomata, store other wastes in falling leaves, resins, or gums, and secrete wastes into the soil. Plants stomata के रास्ते gaseous waste निकालते हैं, dead leaves या resins/gums के रूप में waste store करते हैं, और soil में excrete करते हैं।

NCERT Solutions NCERT Solutions (पाठ्यपुस्तक के हल)

Q1. Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans? Q1. Humans जैसे multi-cellular organisms की oxygen requirements को पूरा करने के लिए diffusion क्यों insufficient है?

Answer: In single-celled organisms, the entire cell surface is in direct contact with the environment, making simple diffusion sufficient. However, in large multi-cellular organisms, body size is complex and most cells are insulated from direct environmental contact. The diffusion pressure is too low to transport oxygen across large cell distances. For instance, diffusion would take 3 years to carry oxygen from lungs to human toes. Hence, specialized respiratory systems and transport pigments (hemoglobin) are essential [NCERT pp.80, 90]. Answer: Single-celled organisms में cell की सारी surface environment के direct contact में रहती है, जिससे simple diffusion काफी होता है। लेकिन large multi-cellular organisms का body size complex होता है और most cells environment के direct contact में नहीं होते। Oxygen को दूर के cells तक transport करने के लिए diffusion pressure बहुत कम है। For example, अगर diffusion से oxygen transport हो, तो lungs से toes तक एक oxygen molecule को पहुँचने में 3 साल लग जाएँगे। इसलिए, specialized respiratory systems और oxygen transport pigment (hemoglobin) ज़रूरी हैं [NCERT pp.80, 90]।

Q2. What criteria do we use to decide whether something is alive? Q2. कोई चीज़ alive है या नहीं, इसे decide करने के लिए हम क्या criteria use करते हैं?

Answer: Visible movements like running, breathing, or growth are indicators of life. However, organisms that are asleep or plants not visibly growing are still alive. Therefore, the primary, decisive criterion is invisible molecular movement (cellular repair, synthesis, and maintenance reactions) occurring continuously inside the cells [NCERT p.79]. Answer: Running, breathing, या growth जैसे visible movements life के indicators हैं। लेकिन asleep organisms या plants जो grow करते हुए नहीं दिखते, वे भी alive हैं। इसलिए, life का primary, decisive criterion invisible molecular movement (cellular repair, synthesis, और maintenance reactions) है जो cells के अंदर continuously चलती रहती हैं [NCERT p.79]।

Q3. What are outside raw materials used by an organism? Q3. किसी organism द्वारा outside से कौनसे raw materials use किए जाते हैं?

Answer: The raw materials taken from the outside include:

Food / Carbon sources (organic compounds) as a source of energy and building blocks.
Oxygen for breaking down food to generate ATP (aerobic respiration).
Water for metabolic reactions and transport.
Minerals and Carbon dioxide (for autotrophs to perform photosynthesis) [NCERT p.80].

Answer: Outside से लिए जाने वाले raw materials में ये शामिल हैं:

Food / Carbon sources (organic compounds) energy और building blocks के source के रूप में।
Oxygen food को break down करके ATP generate करने के लिए (aerobic respiration)।
Water metabolic reactions और transport के लिए।
Minerals और Carbon dioxide (autotrophs के लिए photosynthesis perform करने के लिए) [NCERT p.80]।

Q4. What processes would you consider essential for maintaining life? Answer: Outside से लिए जाने वाले raw materials में ये शामिल हैं:

Food / Carbon sources (organic compounds) energy और building blocks के source के रूप में।
Oxygen food को break down करके ATP generate करने के लिए (aerobic respiration)।
Water metabolic reactions और transport के लिए।
Minerals और Carbon dioxide (autotrophs के लिए photosynthesis perform करने के लिए) [NCERT p.80]।

Answer: The essential maintenance processes are:

Nutrition: Intake and processing of food.
Respiration: Biological oxidation of food to release ATP.
Transportation: Distribution of gases, nutrients, and wastes within the body.
Excretion: Removal of toxic metabolic wastes [NCERT p.80].

Answer: Life को maintain करने के लिए essential processes ये हैं:

Nutrition: Food का intake और processing.
Respiration: Food का biological oxidation जिससे ATP release हो.
Transportation: Body के अंदर gases, nutrients, और wastes का distribution.
Excretion: Toxic metabolic wastes को body से remove करना [NCERT p.80].

Q5. What is the role of the acid in our stomach? Answer: Life को maintain करने के लिए essential processes ये हैं:

Nutrition: Food का intake और processing.
Respiration: Food का biological oxidation जिससे ATP release हो.
Transportation: Body के अंदर gases, nutrients, और wastes का distribution.
Excretion: Toxic metabolic wastes को body से remove करना [NCERT p.80].

Answer: Hydrochloric acid ($HCl$) secreted by gastric glands has two main roles:

It creates an acidic medium (pH ~1.8) required to activate the inactive enzyme pepsinogen into active pepsin, which digests proteins.
It kills harmful bacteria and pathogens entering the stomach along with food [NCERT p.86].

Answer: Gastric glands से secrete होने वाले hydrochloric acid ($HCl$) के दो main roles हैं:

यह एक acidic medium (pH ~1.8) create करता है जो inactive pepsinogen को active pepsin में बदलने के लिए ज़रूरी है, जो proteins को digest करता है।
यह food के साथ stomach में enter करने वाले harmful bacteria और pathogens को मार देता है [NCERT p.86]।

Q6. What is the function of digestive enzymes? Answer: Gastric glands से secrete होने वाले hydrochloric acid ($HCl$) के दो main roles हैं:

यह एक acidic medium (pH ~1.8) create करता है जो inactive pepsinogen को active pepsin में बदलने के लिए ज़रूरी है, जो proteins को digest करता है।
यह food के साथ stomach में enter करने वाले harmful bacteria और pathogens को मार देता है [NCERT p.86]।

Answer: Digestive enzymes are biochemical catalysts (biocatalysts) that hydrolyze complex, insoluble food polymers (like starch, proteins, and fats) into simple, soluble, and absorbable monomers (like glucose, amino acids, fatty acids, and glycerol) so they can enter the bloodstream [NCERT p.85]. Digestive enzymes का क्या काम होता है?

Q7. How is the small intestine designed to absorb digested food? Answer: Digestive enzymes biochemical catalysts (biocatalysts) होते हैं जो complex, insoluble food polymers (जैसे starch, proteins, और fats) को simple, soluble, और absorbable monomers (जैसे glucose, amino acids, fatty acids, और glycerol) में hydrolyze (break down) करते हैं ताकि ये bloodstream में enter कर सकें [NCERT p.85]।

Answer: The small intestine is highly adapted for absorption:

Its inner lining has millions of finger-like projections called villi, which vastly increase the absorption surface area.
The villi are richly supplied with blood capillaries to immediately carry absorbed food into the bloodstream.
The wall of the small intestine is thin, allowing rapid diffusion of nutrients [NCERT p.86].

Answer: Small intestine absorption के लिए highly adapted है:

इसकी inner lining पर millions of finger-like projections होते हैं जिन्हें villi कहते हैं, जो absorption के लिए surface area को vastly increase कर देते हैं।
Villi में rich blood capillary network होता है जो absorbed food को immediately bloodstream में transfer करता है।
Small intestine की wall thin होती है, जिससे nutrients का rapid diffusion हो सकता है [NCERT p.86]।

Solved PYQs Answer: Small intestine absorption के लिए highly adapted है:

इसकी inner lining पर millions of finger-like projections होते हैं जिन्हें villi कहते हैं, जो absorption के लिए surface area को vastly increase कर देते हैं।

Villi में rich blood capillary network होता है जो absorbed food को immediately bloodstream में transfer करता है।

Small intestine की wall thin होती है, जिससे nutrients का rapid diffusion हो सकता है [NCERT p.86]।

[1 Mark] Write the balanced chemical equation representing photosynthesis. Solved PYQs (विगत वर्षों के प्रश्न)

Answer: $$6CO_2 + 12H_2O \xrightarrow[\text{Sunlight}]{\text{Chlorophyll}} C_6H_{12}O_6 + 6O_2 + 6H_2O$$ Answer: $$6CO_2 + 12H_2O \xrightarrow[\text{Sunlight}]{\text{Chlorophyll}} C_6H_{12}O_6 + 6O_2 + 6H_2O$$

[2 Marks] Differentiate between blood and lymph. Answer:

Answer:

Feature	Blood	Lymph
Color	Red (due to hemoglobin)	Colorless or pale straw-colored
Cells	Contains RBCs, WBCs, and platelets	Contains only WBCs (lymphocytes)
Proteins	Contains more proteins	Contains fewer proteins

[NCERT p.94] Answer:

Feature (लक्षण)	Blood (रुधिर)	Lymph (लसीका)
Color (रंग)	Red (hemoglobin के कारण)	Colorless या pale straw-colored
Cells (कोशिकाएँ)	इसमें RBCs, WBCs, और platelets होते हैं	इसमें केवल WBCs (lymphocytes) होते हैं
Proteins (प्रोटीन)	इसमें proteins अधिक मात्रा में होते हैं	इसमें proteins कम मात्रा में होते हैं

[NCERT p.94]

[3 Marks] Explain the three pathways of glucose breakdown in organisms. Answer:

Answer: Glucose is first converted into 3-carbon pyruvate in the cytoplasm. Pyruvate then breaks down along three pathways:

Anaerobic (Yeast): Occurs in the absence of oxygen, yielding ethanol, carbon dioxide, and 2 ATP molecules.
Lack of Oxygen (Muscles): Occurs during intense exercise, converting pyruvate to lactic acid and 2 ATP.
Aerobic (Mitochondria): Occurs in the presence of oxygen, completely breaking pyruvate into carbon dioxide, water, and 36-38 ATP molecules.

[NCERT p.88] Answer: Cytoplasm में glucose सबसे पहले 3-carbon pyruvate में convert होता है। इसके बाद pyruvate तीन pathways के द्वारा break down होता है:

Anaerobic (Yeast): Oxygen की absence में होता है, जिससे ethanol, carbon dioxide, और 2 ATP molecules बनते हैं।
Lack of Oxygen (Muscles): Heavy exercise के दौरान होता है, जिसमें pyruvate lactic acid और 2 ATP में convert होता है।
Aerobic (Mitochondria): Oxygen की presence में होता है, जिसमें pyruvate complete break down होकर carbon dioxide, water, और 36-38 ATP molecules बनाता है।

[NCERT p.88]

[5 Marks] Draw a schematic representation of double circulation in human beings and explain its significance. [3 Marks] Organisms में glucose breakdown के तीन pathways को explain करें।

Answer: Double circulation refers to the system where blood passes through the heart twice in one complete cardiac cycle:

Pulmonary Circulation: Deoxygenated blood is pumped from the right ventricle of the heart to the lungs via the pulmonary artery. In the lungs, blood releases carbon dioxide and absorbs oxygen, returning as oxygenated blood to the left atrium via the pulmonary vein.
Systemic Circulation: Oxygenated blood is pumped from the left ventricle to all body organs via the aorta. After distributing oxygen, deoxygenated blood is returned to the right atrium via the vena cava.

Significance: It keeps oxygenated and deoxygenated blood completely separate. This ensures a highly efficient supply of oxygen to body cells, which is essential for warm-blooded animals (birds and mammals) to maintain constant body temperature. [NCERT p.92] Answer: Double circulation वो system है जिसमें blood एक complete cardiac cycle में heart से दो बार गुज़रता है:

Pulmonary Circulation: Deoxygenated blood right ventricle से pulmonary artery के रास्ते lungs तक pump किया जाता है। Lungs में carbon dioxide release होती है और oxygen absorb होती है, और oxygenated blood pulmonary vein के रास्ते left atrium में वापस आता है।
Systemic Circulation: Left ventricle से oxygenated blood aorta के रास्ते सारे body organs तक pump किया जाता है। Oxygen distribute करने के बाद, deoxygenated blood vena cava के रास्ते right atrium में वापस आता है।

Significance: यह system oxygenated और deoxygenated blood को completely separate रखता है। इससे body cells को highly efficient oxygen supply मिलती है, जो warm-blooded animals (birds और mammals) के लिए body temperature constant रखने के लिए essential है। [NCERT p.92]