Class 10th Science Chapter 5 – Life Processes | Double Circulation, Blood Vessels and Lymph

🫀 Life Processes – Double Circulation

Blood Vessels and Lymph | Class 10 Science | CBSE + Foundation + Competitive

🫀 Double Circulation, Blood Vessels and Lymph

🔬 Animated Diagram – Double Circulation

Diagram Flow:
🔵 Body → Right Heart → Lungs → 🔴 Left Heart → Body

नीली लाइन = Deoxygenated Blood
लाल लाइन = Oxygenated Blood

1. Double Circulation – द्विगुणित परिसंचरण

English:
In humans, blood passes through the heart twice during one complete cycle of circulation. This is called double circulation.

हिन्दी:
मानव में एक पूर्ण परिसंचरण चक्र के दौरान रक्त हृदय से दो बार गुजरता है। इसे द्विगुणित परिसंचरण कहते हैं।

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2. Two Parts of Double Circulation

1. Pulmonary Circulation – फुफ्फुसीय परिसंचरण
Heart ↔ Lungs

2. Systemic Circulation – शरीरगत परिसंचरण
Heart ↔ Body

3. Pulmonary Circulation

Deoxygenated blood from the right ventricle is pumped to the lungs through the pulmonary artery. In lungs:

• Carbon dioxide is released.
• Oxygen is absorbed.

Oxygenated blood returns to the left atrium through pulmonary veins.

Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium

4. Systemic Circulation

Oxygenated blood from the left ventricle is pumped into the aorta. The aorta distributes blood to different parts of the body. After exchange at tissues, deoxygenated blood returns to the right atrium through the vena cava.

Left Ventricle → Aorta → Body Tissues → Vena Cava → Right Atrium

5. Importance of Double Circulation

Double circulation:

• Prevents significant mixing of oxygenated and deoxygenated blood.
• Provides efficient oxygen supply.
• Maintains high oxygen concentration in systemic circulation.
• Supports high energy requirements of humans.

6. Blood Vessels – रक्त वाहिकाएँ

The three major types of blood vessels are:

1. Arteries – धमनियाँ
2. Veins – शिराएँ
3. Capillaries – केशिकाएँ

7. Arteries – धमनियाँ

Arteries carry blood away from the heart. Their walls are thick, muscular and elastic because blood flows through them under relatively high pressure.

Example: Aorta

Important Exception: Pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.

8. Veins – शिराएँ

Veins carry blood towards the heart. They generally have thinner walls and valves that help prevent backflow.

Important Exception: Pulmonary veins carry oxygenated blood from lungs to the left atrium.

9. Capillaries – केशिकाएँ

Capillaries are extremely thin blood vessels. Their walls are usually only one cell thick. They connect the smallest arteries with the smallest veins and allow exchange between blood and tissues.

10. Artery vs Vein vs Capillary

Feature	Artery	Vein	Capillary
Direction	Away from heart	Towards heart	Exchange vessels
Wall	Thick and elastic	Relatively thin	Very thin
Pressure	High	Low	Low
Valves	Generally absent	Present	Absent
Main function	Transport away	Return to heart	Exchange substances

11. Lymph – लसीका

English:
Lymph is a colourless fluid that forms part of the lymphatic system.

हिन्दी:
लसीका एक रंगहीन द्रव है जो लसीका तंत्र का भाग है। यह ऊतक द्रव के संतुलन, प्रतिरक्षा तथा वसा के परिवहन में महत्वपूर्ण भूमिका निभाता है।

12. Functions of Lymph

• Returns excess tissue fluid to the blood.
• Helps in defence and immunity.
• Transports absorbed fats from the small intestine.
• Helps maintain fluid balance in tissues.

13. Blood vs Lymph

Blood	Lymph
Red due to haemoglobin in RBCs.	Usually colourless.
Contains RBCs, WBCs and platelets.	Contains mainly lymphocytes among its cells.
Transports oxygen, nutrients and wastes.	Returns tissue fluid and supports immunity.
Important in rapid transport.	Important in fluid balance and immune functions.

14. Tissue Fluid – ऊतक द्रव

Some fluid moves out of blood capillaries into the spaces between cells. This fluid surrounds cells and allows exchange of substances. Excess tissue fluid is collected by lymphatic vessels and becomes lymph.

15. Lymphatic System

The lymphatic system includes:

• Lymph
• Lymphatic capillaries
• Lymphatic vessels
• Lymph nodes

It plays an important role in fluid balance and immunity.

16. Role of Lymph in Fat Absorption

Special lymph vessels called lacteals are present inside intestinal villi. They help transport absorbed fats from the small intestine into the lymphatic system.

17. Valves in Circulatory System

Valves prevent the backward movement of blood. They are especially important in veins because blood pressure is relatively low there. Heart valves also ensure one-way movement through the heart.

18. Why is Left Ventricle Thick?

The left ventricle pumps blood to the entire body. Therefore, it needs to generate greater pressure and has a thicker muscular wall than the right ventricle.

19. Important Exceptions

Pulmonary artery: Deoxygenated blood

Pulmonary vein: Oxygenated blood

Remember: Artery = Away from heart
Vein = Towards heart

20. Blood Pressure

Blood pressure is the pressure exerted by blood on the walls of blood vessels.

Systolic pressure: Pressure during ventricular contraction.
Diastolic pressure: Pressure during ventricular relaxation.

Reference value often expressed as ≈ 120/80 mm Hg

21. 30 MCQs – Multiple Choice Questions

Q1. Humans show which type of circulation?

A) Double circulation

B) Single circulation

C) Open circulation

D) Incomplete circulation

Answer: A) Double circulation

Q2. Pulmonary circulation occurs between:

A) Heart and kidney

B) Heart and lungs

C) Lungs and kidney

D) Heart and liver

Answer: B) Heart and lungs

Q3. Systemic circulation occurs between:

A) Heart and lungs

B) Lungs and brain

C) Heart and body

D) Kidney and heart

Answer: C) Heart and body

Q4. Which vessel carries deoxygenated blood to lungs?

A) Aorta

B) Pulmonary vein

C) Vena cava

D) Pulmonary artery

Answer: D) Pulmonary artery

Q5. Which vessel carries oxygenated blood from lungs?

A) Pulmonary vein

B) Pulmonary artery

C) Vena cava

D) Aorta

Answer: A) Pulmonary vein

Q6. Blood flows away from heart through:

A) Veins

B) Arteries

C) Capillaries

D) Lymph vessels

Answer: B) Arteries

Q7. Blood flows towards the heart through:

A) Arteries

B) Capillaries

C) Veins

D) Aorta

Answer: C) Veins

Q8. The thinnest blood vessels are:

A) Veins

B) Arteries

C) Aorta

D) Capillaries

Answer: D) Capillaries

Q9. Valves are commonly present in:

A) Veins

B) Capillaries

C) Arterioles

D) Plasma

Answer: A) Veins

Q10. The main artery from the left ventricle is:

A) Vena cava

B) Aorta

C) Pulmonary vein

D) Pulmonary artery

Answer: B) Aorta

Q11. Which vessel returns blood from body to heart?

A) Aorta

B) Pulmonary artery

C) Vena cava

D) Pulmonary vein

Answer: C) Vena cava

Q12. Lymph is generally:

A) Red

B) Blue

C) Green

D) Colourless

Answer: D) Colourless

Q13. Lymph helps in:

A) Immunity

B) Only respiration

C) Only digestion

D) Only heartbeat

Answer: A) Immunity

Q14. Lacteals are associated with absorption of:

A) Proteins

B) Fats

C) Minerals

D) Water

Answer: B) Fats

Q15. Which circulation oxygenates blood?

A) Systemic

B) Coronary

C) Pulmonary

D) Lymphatic

Answer: C) Pulmonary

Q16. Left ventricle pumps blood to:

A) Lungs

B) Right atrium

C) Left atrium

D) Entire body

Answer: D) Entire body

Q17. Which vessel has relatively thick and elastic walls?

A) Artery

B) Vein

C) Capillary

D) Lymph vessel

Answer: A) Artery

Q18. Which blood vessel generally has the lowest pressure?

A) Aorta

B) Vein

C) Artery

D) Pulmonary artery

Answer: B) Vein

Q19. Exchange of substances mainly occurs through:

A) Aorta

B) Veins

C) Capillaries

D) Vena cava

Answer: C) Capillaries

Q20. Tissue fluid is collected by:

A) Arteries

B) Veins only

C) Aorta

D) Lymphatic vessels

Answer: D) Lymphatic vessels

Q21. The wall of left ventricle is:

A) Thickest

B) Thinnest

C) Same as atria

D) Absent

Answer: A) Thickest

Q22. The pulmonary artery originates from:

A) Left atrium

B) Right ventricle

C) Left ventricle

D) Right atrium

Answer: B) Right ventricle

Q23. Pulmonary veins open into:

A) Right atrium

B) Right ventricle

C) Left atrium

D) Left ventricle

Answer: C) Left atrium

Q24. Which prevents backflow of blood?

A) RBCs

B) Plasma

C) Capillaries

D) Valves

Answer: D) Valves

Q25. Systemic circulation begins from:

A) Left ventricle

B) Right ventricle

C) Right atrium

D) Left atrium

Answer: A) Left ventricle

Q26. Pulmonary circulation ends when oxygenated blood reaches:

A) Right atrium

B) Left atrium

C) Right ventricle

D) Aorta

Answer: B) Left atrium

Q27. Lymph mainly helps return excess:

A) Oxygen

B) Carbon dioxide

C) Tissue fluid

D) Haemoglobin

Answer: C) Tissue fluid

Q28. Which structure is important for fat transport from intestine?

A) Aorta

B) Vena cava

C) Pulmonary artery

D) Lacteals

Answer: D) Lacteals

Q29. The direction of blood flow is determined by whether a vessel carries blood:

A) Towards or away from heart

B) With or without oxygen

C) With or without RBCs

D) With or without plasma

Answer: A) Towards or away from heart

Q30. Double circulation helps humans mainly by:

A) Stopping digestion

B) Efficient oxygen delivery

C) Preventing breathing

D) Stopping blood flow

Answer: B) Efficient oxygen delivery

22. 30 Subjective Questions with Answers

1 Mark Q1. What is double circulation?

Answer: In humans, blood passes through the heart twice during one complete cycle of circulation.

1 Mark Q2. Name the two types of circulation.

Answer: Pulmonary circulation and systemic circulation.

1 Mark Q3. Name the blood vessel that carries blood from heart to lungs.

Answer: Pulmonary artery.

1 Mark Q4. Name the vessel that carries oxygenated blood from lungs to heart.

Answer: Pulmonary vein.

1 Mark Q5. What is lymph?

Answer: Lymph is a colourless fluid of the lymphatic system involved in fluid balance, immunity and fat transport.

1 Mark Q6. Name the smallest blood vessels.

Answer: Capillaries.

2 Marks Q7. Define pulmonary circulation.

Answer: It is the circulation of blood between the heart and lungs. Deoxygenated blood goes to lungs and oxygenated blood returns to the left atrium.

2 Marks Q8. Define systemic circulation.

Answer: It is the circulation of oxygenated blood from the left ventricle to the body and return of deoxygenated blood to the right atrium.

2 Marks Q9. Write two functions of lymph.

Answer:

1. Returns excess tissue fluid to blood.
2. Helps in immunity and transport of absorbed fats.

2 Marks Q10. Why are valves present in veins?

Answer: Veins carry blood at relatively low pressure. Valves prevent the backward flow of blood and help maintain one-way movement towards the heart.

2 Marks Q11. What are capillaries?

Answer: Capillaries are very thin blood vessels where exchange of gases, nutrients and wastes occurs between blood and tissues.

2 Marks Q12. Why is double circulation important?

Answer: It keeps oxygenated and deoxygenated blood largely separate and ensures efficient oxygen supply to tissues.

3 Marks Q13. Differentiate between arteries and veins.

Arteries	Veins
Carry blood away from heart.	Carry blood towards heart.
Thick and elastic walls.	Relatively thin walls.
Generally no valves.	Valves are generally present.

3 Marks Q14. Explain the role of capillaries.

Answer: Capillaries have very thin walls and form networks around tissues. They allow oxygen, nutrients and water to move from blood to tissues and carbon dioxide and wastes to move into blood.

3 Marks Q15. Explain pulmonary circulation.

Answer: Deoxygenated blood from the right ventricle travels through the pulmonary artery to the lungs. It becomes oxygenated and returns through pulmonary veins to the left atrium.

3 Marks Q16. Explain systemic circulation.

Answer: Oxygenated blood is pumped from the left ventricle through the aorta to body tissues. Deoxygenated blood returns through veins and vena cava to the right atrium.

3 Marks Q17. Explain two important functions of lymph.

Answer: Lymph returns excess tissue fluid to the bloodstream and helps in immunity. It also transports absorbed fats from the intestine through lacteals.

3 Marks Q18. Why is pulmonary artery called an exception?

Answer: It is an artery because it carries blood away from the heart, but the blood it carries is deoxygenated.

4 Marks Q19. Explain double circulation with its two components.

Answer: Double circulation has two components:

1. Pulmonary circulation: Right ventricle → lungs → left atrium.
2. Systemic circulation: Left ventricle → body → right atrium.

Thus blood passes through the heart twice in one complete cycle.

4 Marks Q20. Compare pulmonary and systemic circulation.

Pulmonary	Systemic
Heart ↔ lungs	Heart ↔ body
Oxygenates blood	Supplies oxygen to tissues
Right ventricle involved initially	Left ventricle involved initially

4 Marks Q21. Explain the structure and function of arteries, veins and capillaries.

Answer: Arteries have thick elastic walls and carry blood away from the heart. Veins have relatively thin walls and valves and carry blood towards the heart. Capillaries are microscopic vessels with very thin walls and allow exchange of substances with tissues.

4 Marks Q22. Explain the role of lymph in the human body.

Answer: Lymph collects excess tissue fluid and returns it to the bloodstream. It helps in immunity and transports absorbed fats from the small intestine through lacteals.

5 Marks Q23. Describe the complete pathway of blood in double circulation.

Answer:
Body → Vena Cava → Right Atrium → Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Veins → Left Atrium → Left Ventricle → Aorta → Body.

This completes pulmonary as well as systemic circulation.

5 Marks Q24. Explain why arteries and veins have different structures.

Answer: Arteries receive blood directly from the heart under relatively high pressure, so their walls are thick, muscular and elastic. Veins return blood at lower pressure and therefore have thinner walls. Valves in veins prevent backward flow.

5 Marks Q25. Explain the importance of capillaries in circulation.

Answer: Capillaries have extremely thin walls and form networks near body cells. Their large total surface area and thin walls facilitate exchange of oxygen, carbon dioxide, nutrients, water and wastes between blood and tissues.

5 Marks Q26. Differentiate between blood and lymph.

Blood	Lymph
Usually red.	Usually colourless.
Contains RBCs, WBCs and platelets.	Contains mainly lymphocytes among its cells.
Transports oxygen and nutrients.	Helps fluid balance and immunity.
Rapid circulatory transport.	Returns excess tissue fluid.

6 Marks Q27. Explain double circulation in humans with a suitable flow sequence.

Answer: Double circulation consists of pulmonary and systemic circulation.

Pulmonary circulation: Right ventricle → Pulmonary artery → Lungs → Pulmonary veins → Left atrium.

Systemic circulation: Left ventricle → Aorta → Body tissues → Vena cava → Right atrium.

This arrangement keeps oxygenated and deoxygenated blood largely separate and provides efficient oxygen supply to the body.

6 Marks Q28. Explain how blood vessels are adapted to their functions.

Answer:

• Arteries: Thick, muscular and elastic walls withstand high pressure.
• Veins: Thinner walls and valves assist return of blood at low pressure.
• Capillaries: One-cell-thick walls permit rapid exchange of substances.

Thus, their structures are suited to their specific roles in circulation.

6 Marks Q29. Explain the formation and functions of lymph.

Answer: Some fluid filters out of blood capillaries into the spaces between cells and forms tissue fluid. Excess tissue fluid is collected by lymphatic capillaries and becomes lymph.

Functions:

• Returns excess tissue fluid to blood.
• Helps maintain fluid balance.
• Participates in immunity.
• Transports absorbed fats through lacteals.

6 Marks Q30. Explain why humans require double circulation.

Answer: Humans are active organisms with high energy requirements. Their cells need a continuous and efficient supply of oxygen for cellular respiration. The four-chambered heart separates oxygenated and deoxygenated blood. Pulmonary circulation oxygenates blood, while systemic circulation supplies oxygen-rich blood to the body. Therefore, double circulation provides efficient oxygen delivery and supports the high metabolic needs of humans.

23. HOTS / Application Based Questions

HOTS 1: Why is the pulmonary artery an artery even though it carries deoxygenated blood?

Answer: The terms artery and vein are based on the direction of blood flow. An artery carries blood away from the heart. Therefore, pulmonary artery is an artery despite carrying deoxygenated blood.

HOTS 2: Why are capillaries suitable for exchange of substances?

Answer: Their walls are extremely thin, usually one cell thick, providing a short diffusion distance between blood and tissues.

HOTS 3: What would happen if veins had no valves?

Answer: Blood could flow backward more easily, especially against gravity, making return of blood to the heart less efficient.

HOTS 4: Why is separation of oxygenated and deoxygenated blood useful?

Answer: It allows efficient delivery of oxygen-rich blood to tissues, supporting the high energy requirement of the human body.

24. CBSE Golden Points ⭐

• Human beings have double circulation.
• Pulmonary circulation occurs between heart and lungs.
• Systemic circulation occurs between heart and body.
• Pulmonary artery carries deoxygenated blood.
• Pulmonary vein carries oxygenated blood.
• Aorta carries blood from left ventricle to body.
• Vena cava returns blood from body to right atrium.
• Arteries carry blood away from heart.
• Veins carry blood towards heart.
• Capillaries are sites of exchange.
• Veins generally contain valves.
• Lymph returns excess tissue fluid to blood.
• Lymph helps in immunity.
• Lacteals transport absorbed fats.
• Left ventricle has the thickest muscular wall.

25. Quick Revision – एक नजर में

🔵 Body → Vena Cava → Right Atrium → Right Ventricle → Pulmonary Artery → Lungs

🔴 Lungs → Pulmonary Veins → Left Atrium → Left Ventricle → Aorta → Body

🩸 Artery = Away from Heart
🩸 Vein = Towards Heart
🔬 Capillary = Exchange
💧 Lymph = Tissue Fluid + Immunity + Fat Transport

⭐ Exam Mantra:

Right Heart → Lungs
Left Heart → Body

Pulmonary Artery → Deoxygenated Blood
Pulmonary Vein → Oxygenated Blood

Artery = Away | Vein = Towards

Class 10th Science Chapter 5 – Life Processes | Transportation in Humans – Blood, Heart and Circulatory System

🫀 Life Processes – Transportation in Humans

Blood, Heart and Circulatory System | Class 10 Science | CBSE + Foundation + Competitive

🫀 Transportation in Humans – Blood, Heart and Circulatory System

🔬 Animated Diagram – Human Double Circulation

Animation Concept: नीली dashed lines deoxygenated blood को दर्शाती हैं और लाल dashed lines oxygenated blood को। Heart का animation उसके rhythmic contraction को दिखाता है।

1. Transportation in Humans – मानव में परिवहन

English:
Transportation is the process by which useful substances such as oxygen, nutrients, hormones and water are carried to different parts of the body, while waste products such as carbon dioxide are transported to organs where they can be removed.

हिन्दी:
परिवहन वह प्रक्रिया है जिसके द्वारा ऑक्सीजन, पोषक पदार्थ, हार्मोन तथा जल जैसे आवश्यक पदार्थ शरीर के विभिन्न भागों तक पहुँचाए जाते हैं तथा कार्बन डाइऑक्साइड जैसे अपशिष्ट पदार्थों को निष्कासन अंगों तक पहुँचाया जाता है।

Human transport system mainly consists of:

• Blood – रक्त
• Heart – हृदय
• Blood vessels – रक्त वाहिकाएँ

2. Blood – रक्त

English:
Blood is a fluid connective tissue that transports oxygen, carbon dioxide, digested food, hormones and waste products throughout the body.

हिन्दी:
रक्त एक तरल संयोजी ऊतक है जो शरीर में ऑक्सीजन, कार्बन डाइऑक्साइड, पचा हुआ भोजन, हार्मोन तथा अपशिष्ट पदार्थों का परिवहन करता है।

3. Components of Blood – रक्त के घटक

Component	मुख्य कार्य
Plasma	Food, hormones, CO₂ और waste products का transport
RBCs / Red Blood Cells	Oxygen का transport
WBCs / White Blood Cells	Body defence और immunity
Platelets	Blood clotting

4. Plasma – प्लाज्मा

English:
Plasma is the liquid part of blood. It transports dissolved nutrients, hormones, carbon dioxide and waste materials.

हिन्दी:
प्लाज्मा रक्त का तरल भाग है। इसमें पोषक पदार्थ, हार्मोन, कार्बन डाइऑक्साइड तथा अपशिष्ट पदार्थ घुले हुए रूप में परिवहन किए जाते हैं।

5. Red Blood Cells – लाल रक्त कोशिकाएँ

RBCs contain haemoglobin, a red pigment that binds with oxygen.

RBC का मुख्य कार्य:

• Oxygen transport
• Haemoglobin contains iron
• Human mature RBCs normally lack a nucleus

Haemoglobin + Oxygen ⇌ Oxyhaemoglobin

CBSE Point: Haemoglobin oxygen के साथ reversible combination बनाता है।

6. White Blood Cells – श्वेत रक्त कोशिकाएँ

WBCs protect the body against pathogens and foreign substances.

हिन्दी: श्वेत रक्त कोशिकाएँ रोगजनकों से शरीर की रक्षा करती हैं तथा प्रतिरक्षा में महत्वपूर्ण भूमिका निभाती हैं।

7. Platelets – प्लेटलेट्स

Platelets help in blood clotting and prevent excessive blood loss after injury.

चोट लगने पर प्लेटलेट्स रक्त का थक्का बनाने में सहायता करते हैं।

8. Human Heart – मानव हृदय

English:
The human heart is a muscular organ that pumps blood throughout the body.

हिन्दी:
मानव हृदय एक पेशीय अंग है जो रक्त को पूरे शरीर में पंप करता है।

Human heart has four chambers:

1. Right Atrium – दायाँ अलिंद
2. Right Ventricle – दायाँ निलय
3. Left Atrium – बायाँ अलिंद
4. Left Ventricle – बायाँ निलय

9. Septum – सेप्टम

Septum is a muscular partition that separates the right and left sides of the heart.

Importance:
It prevents mixing of oxygenated and deoxygenated blood.

10. Atria – अलिंद

Atria are the upper chambers of the heart.

• Right atrium receives deoxygenated blood from the body.
• Left atrium receives oxygenated blood from the lungs.

11. Ventricles – निलय

Ventricles are the lower chambers.

• Right ventricle pumps blood to lungs.
• Left ventricle pumps blood to the entire body.

Important: Left ventricle has a thicker muscular wall because it has to pump blood throughout the body.

12. Valves – वाल्व

Heart valves ensure that blood flows in only one direction. Functions:

• Prevent backflow of blood
• Maintain one-way movement
• Help efficient circulation

13. Blood Vessels – रक्त वाहिकाएँ

Blood Vessel	Direction	Main Feature
Artery	Heart → Body	Thick, elastic walls
Vein	Body → Heart	Thinner walls; valves present
Capillary	Connects arteries and veins	Very thin walls

14. Arteries – धमनियाँ

Arteries carry blood away from the heart. Most arteries carry oxygenated blood. Exception: Pulmonary artery carries deoxygenated blood from right ventricle to lungs.

15. Veins – शिराएँ

Veins carry blood towards the heart. Most veins carry deoxygenated blood. Exception: Pulmonary vein carries oxygenated blood from lungs to left atrium.

16. Capillaries – केशिकाएँ

Capillaries are microscopic blood vessels with very thin walls. They allow exchange of:

• Oxygen
• Carbon dioxide
• Nutrients
• Water
• Waste products

17. Double Circulation – द्विगुणित परिसंचरण

In humans, blood passes through the heart twice during one complete cycle of circulation. This is called double circulation.

It consists of:

1. Pulmonary circulation
2. Systemic circulation

18. Pulmonary Circulation – फुफ्फुसीय परिसंचरण

Deoxygenated blood travels from the right ventricle to the lungs through the pulmonary artery. In lungs, CO₂ is removed and oxygen is absorbed. Oxygenated blood returns to the left atrium through pulmonary veins.

Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium

19. Systemic Circulation – शरीरगत परिसंचरण

Oxygenated blood is pumped from the left ventricle to the entire body through the aorta. After exchange in tissues, deoxygenated blood returns to the right atrium through veins.

Left Ventricle → Aorta → Body Tissues → Vena Cava → Right Atrium

20. Complete Path of Blood – रक्त का पूरा मार्ग

Body → Vena Cava → Right Atrium → Right Ventricle → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium → Left Ventricle → Aorta → Body

21. Why is Double Circulation Necessary?

Double circulation ensures that oxygenated and deoxygenated blood remain largely separated. This provides efficient oxygen supply to body tissues. It supports the high energy requirement of humans.

22. Heartbeat – हृदय की धड़कन

A heartbeat consists of rhythmic contraction and relaxation of heart muscles.

• Systole: Contraction of heart chambers.
• Diastole: Relaxation of heart chambers.

23. Cardiac Cycle – हृदय चक्र

The cardiac cycle is the sequence of contraction and relaxation of the heart chambers during one heartbeat. It ensures continuous pumping of blood.

24. Blood Pressure – रक्तचाप

Blood pressure is the pressure exerted by blood against the walls of blood vessels. It is commonly measured using a sphygmomanometer.

Systolic pressure: Pressure during ventricular contraction.
Diastolic pressure: Pressure during ventricular relaxation.

Normal reference value ≈ 120/80 mm Hg

25. Lymph – लसीका

Lymph is a colourless fluid involved in transport and immune functions. Functions:

• Returns excess tissue fluid to blood
• Transports absorbed fats from intestine
• Helps in immunity

26. Blood vs Lymph

Blood	Lymph
Usually red due to haemoglobin	Usually colourless
Contains RBCs, WBCs and platelets	Contains mainly lymphocytes
Rapid transport system	Returns excess tissue fluid
Transports oxygen efficiently through RBCs	Important in immunity and fat transport

27. Transport of Carbon Dioxide

Carbon dioxide produced during cellular respiration is transported by blood to the lungs. A significant portion of CO₂ is transported in dissolved/converted forms in plasma, especially as bicarbonate ions.

28. Transport of Oxygen

Oxygen enters blood at the lungs and combines with haemoglobin in RBCs. It is then transported to body tissues. At tissues, oxygen is released for cellular respiration.

O₂ + Haemoglobin ⇌ Oxyhaemoglobin

29. Artery vs Vein vs Capillary

Feature	Artery	Vein	Capillary
Direction	Away from heart	Towards heart	Exchange vessels
Wall	Thick	Thin	Very thin
Valves	Generally absent	Present	Absent
Pressure	High	Low	Low

30. CBSE Golden Points ⭐

• Heart has four chambers.
• Septum separates right and left sides of heart.
• Right ventricle pumps blood to lungs.
• Left ventricle pumps blood to the entire body.
• Pulmonary artery carries deoxygenated blood.
• Pulmonary vein carries oxygenated blood.
• Aorta is the main artery carrying blood from the left ventricle.
• Vena cava brings deoxygenated blood to the right atrium.
• RBCs contain haemoglobin.
• WBCs help in defence.
• Platelets help in clotting.
• Capillaries are sites of exchange.
• Humans show double circulation.
• Valves prevent backflow.
• Left ventricular wall is thicker than right ventricular wall.

31. 30 MCQs – Multiple Choice Questions

Q1. The fluid connective tissue in humans is:

A) Blood

B) Bone

C) Cartilage

D) Muscle

Answer: A) Blood

Q2. Which component of blood transports oxygen?

A) Plasma

B) RBCs

C) Platelets

D) WBCs

Answer: B) RBCs

Q3. Haemoglobin is present mainly in:

A) Plasma

B) WBCs

C) RBCs

D) Platelets

Answer: C) RBCs

Q4. Which blood component helps in clotting?

A) RBC

B) Plasma

C) WBC

D) Platelets

Answer: D) Platelets

Q5. The human heart has:

A) 4 chambers

B) 2 chambers

C) 3 chambers

D) 5 chambers

Answer: A) 4 chambers

Q6. Which chamber receives deoxygenated blood from the body?

A) Left atrium

B) Right atrium

C) Left ventricle

D) Right ventricle

Answer: B) Right atrium

Q7. Which chamber pumps blood to the lungs?

A) Left atrium

B) Left ventricle

C) Right ventricle

D) Right atrium

Answer: C) Right ventricle

Q8. Which chamber pumps oxygenated blood to the whole body?

A) Right atrium

B) Right ventricle

C) Left atrium

D) Left ventricle

Answer: D) Left ventricle

Q9. The main artery leaving the left ventricle is:

A) Aorta

B) Vena cava

C) Pulmonary vein

D) Pulmonary artery

Answer: A) Aorta

Q10. Pulmonary artery carries:

A) Oxygenated blood to body

B) Deoxygenated blood to lungs

C) Oxygenated blood to lungs

D) Deoxygenated blood to heart

Answer: B) Deoxygenated blood to lungs

Q11. Pulmonary vein carries:

A) Deoxygenated blood

B) Mixed blood

C) Oxygenated blood

D) Lymph

Answer: C) Oxygenated blood

Q12. Septum prevents:

A) Blood clotting

B) Blood pressure

C) Digestion

D) Mixing of oxygenated and deoxygenated blood

Answer: D) Mixing of oxygenated and deoxygenated blood

Q13. The thickest wall is found in:

A) Left ventricle

B) Right atrium

C) Left atrium

D) Right ventricle

Answer: A) Left ventricle

Q14. Blood vessels with very thin walls are:

A) Arteries

B) Capillaries

C) Veins

D) Aorta

Answer: B) Capillaries

Q15. Valves are particularly important in:

A) Arteries

B) Capillaries

C) Veins

D) Plasma

Answer: C) Veins

Q16. Blood pressure is measured using:

A) Barometer

B) Thermometer

C) Hygrometer

D) Sphygmomanometer

Answer: D) Sphygmomanometer

Q17. Contraction of heart muscles is called:

A) Systole

B) Diastole

C) Diffusion

D) Osmosis

Answer: A) Systole

Q18. Relaxation of heart muscles is called:

A) Systole

B) Diastole

C) Pulse

D) Clotting

Answer: B) Diastole

Q19. Which vessel carries blood from body to right atrium?

A) Aorta

B) Pulmonary artery

C) Vena cava

D) Pulmonary vein

Answer: C) Vena cava

Q20. The liquid portion of blood is:

A) RBC

B) WBC

C) Platelets

D) Plasma

Answer: D) Plasma

Q21. WBCs mainly help in:

A) Defence

B) Oxygen transport

C) Clotting

D) Digestion

Answer: A) Defence

Q22. Human beings show:

A) Single circulation

B) Double circulation

C) Open circulation

D) No circulation

Answer: B) Double circulation

Q23. Which organ pumps blood?

A) Kidney

B) Lung

C) Heart

D) Liver

Answer: C) Heart

Q24. Oxygenated blood from lungs enters:

A) Right atrium

B) Right ventricle

C) Left ventricle

D) Left atrium

Answer: D) Left atrium

Q25. Exchange between blood and tissues mainly occurs through:

A) Capillaries

B) Aorta

C) Vena cava

D) Pulmonary artery

Answer: A) Capillaries

Q26. The iron-containing pigment in RBCs is:

A) Chlorophyll

B) Haemoglobin

C) Melanin

D) Insulin

Answer: B) Haemoglobin

Q27. Which blood vessel carries oxygenated blood from lungs?

A) Vena cava

B) Pulmonary artery

C) Pulmonary vein

D) Renal vein

Answer: C) Pulmonary vein

Q28. Lymph helps in:

A) Only oxygen transport

B) Only heartbeat

C) Only digestion

D) Immunity and return of tissue fluid

Answer: D) Immunity and return of tissue fluid

Q29. Which chamber has the thickest muscular wall?

A) Left ventricle

B) Right atrium

C) Left atrium

D) Right atrium

Answer: A) Left ventricle

Q30. Which structure prevents backflow of blood in the heart?

A) Septum

B) Valves

C) Capillaries

D) Plasma

Answer: B) Valves

32. 30 Subjective Questions with Answers

1 Mark Q1. What is transportation in humans?

Answer: It is the process of transporting oxygen, nutrients, hormones and wastes throughout the body.

1 Mark Q2. Name the fluid connective tissue of humans.

Answer: Blood.

1 Mark Q3. What is the function of haemoglobin?

Answer: It transports oxygen by combining reversibly with oxygen.

1 Mark Q4. Name the pigment present in RBCs.

Answer: Haemoglobin.

1 Mark Q5. How many chambers are present in the human heart?

Answer: Four.

1 Mark Q6. Name the blood vessel carrying deoxygenated blood from heart to lungs.

Answer: Pulmonary artery.

2 Marks Q7. Write two functions of blood.

Answer:

1. Transport of oxygen and nutrients.
2. Transport of carbon dioxide and wastes.

2 Marks Q8. What are the functions of platelets?

Answer: Platelets help in blood clotting and prevent excessive blood loss.

2 Marks Q9. Differentiate between arteries and veins.

Arteries	Veins
Carry blood away from heart.	Carry blood towards heart.
Walls are thick and elastic.	Walls are relatively thin.

2 Marks Q10. What is the function of septum?

Answer: Septum separates the right and left sides of the heart and prevents mixing of oxygenated and deoxygenated blood.

2 Marks Q11. Why is the wall of the left ventricle thicker?

Answer: The left ventricle pumps blood to the entire body, so it requires greater muscular force.

2 Marks Q12. What is double circulation?

Answer: In one complete circulation, blood passes through the heart twice. It includes pulmonary and systemic circulation.

3 Marks Q13. Explain the functions of RBCs, WBCs and platelets.

Answer:

• RBCs transport oxygen.
• WBCs protect the body against pathogens.
• Platelets help in blood clotting.

3 Marks Q14. Explain the role of plasma.

Answer: Plasma is the liquid part of blood. It transports dissolved nutrients, hormones, carbon dioxide and waste materials.

3 Marks Q15. Explain pulmonary circulation.

Answer: Deoxygenated blood moves from right ventricle to lungs through pulmonary artery. In lungs it gets oxygenated. Oxygenated blood returns to left atrium through pulmonary veins.

3 Marks Q16. Explain systemic circulation.

Answer: Oxygenated blood leaves the left ventricle through the aorta and reaches body tissues. Deoxygenated blood returns to right atrium through vena cava.

3 Marks Q17. What are capillaries? Give their importance.

Answer: Capillaries are very thin blood vessels. They connect small arteries and veins and allow exchange of gases, nutrients, water and wastes with tissues.

3 Marks Q18. Why are valves present in the heart?

Answer: Valves prevent the backward flow of blood and ensure that blood moves in one direction.

4 Marks Q19. Describe the four chambers of the human heart.

Answer:

• Right atrium receives deoxygenated blood from body.
• Right ventricle sends it to lungs.
• Left atrium receives oxygenated blood from lungs.
• Left ventricle pumps oxygenated blood to the body.

4 Marks Q20. Explain the complete pathway of blood through the heart.

Solution:
Body → Vena cava → Right atrium → Right ventricle → Pulmonary artery → Lungs → Pulmonary veins → Left atrium → Left ventricle → Aorta → Body.

4 Marks Q21. Differentiate between pulmonary and systemic circulation.

Pulmonary Circulation	Systemic Circulation
Heart ↔ Lungs	Heart ↔ Body
Oxygenation of blood occurs.	Oxygen is delivered to tissues.

4 Marks Q22. Explain the importance of double circulation in humans.

Answer: Double circulation keeps oxygenated and deoxygenated blood largely separate and ensures efficient oxygen supply to tissues. This supports the high energy requirement of the human body.

5 Marks Q23. Describe the structure and function of the human heart.

Answer: The heart is a muscular organ with four chambers. The right atrium receives deoxygenated blood and passes it to the right ventricle, which pumps it to lungs. The left atrium receives oxygenated blood and passes it to the left ventricle. The left ventricle pumps blood to the entire body. Septum separates the two sides and valves prevent backflow.

5 Marks Q24. Explain the composition and functions of blood.

Answer: Blood consists of plasma, RBCs, WBCs and platelets.

• Plasma transports dissolved substances.
• RBCs transport oxygen.
• WBCs provide defence.
• Platelets help clotting.

Together these components maintain transport, protection and regulation in the body.

5 Marks Q25. Explain the role of arteries, veins and capillaries.

Answer: Arteries carry blood away from the heart and have thick elastic walls. Veins carry blood towards the heart and generally contain valves. Capillaries are microscopic vessels with very thin walls and are the main sites of exchange between blood and tissues.

5 Marks Q26. Explain transport of oxygen and carbon dioxide by blood.

Answer: Oxygen enters blood in lungs and combines with haemoglobin in RBCs. It is transported to tissues where it is released. Carbon dioxide produced in tissues is transported by blood to lungs, where it is removed during exhalation.

6 Marks Q27. Draw and explain the double circulation in humans.

Answer:
Double circulation consists of pulmonary and systemic circulation.

Pulmonary: Right ventricle → Pulmonary artery → Lungs → Pulmonary veins → Left atrium.

Systemic: Left ventricle → Aorta → Body tissues → Vena cava → Right atrium.

It prevents significant mixing of oxygenated and deoxygenated blood and ensures efficient oxygen delivery.

6 Marks Q28. Explain why separation of oxygenated and deoxygenated blood is important in humans.

Answer: Humans have high energy requirements. Efficient respiration requires a continuous supply of oxygen. The four-chambered heart and septum keep oxygen-rich and oxygen-poor blood largely separate. Therefore, highly oxygenated blood can be supplied efficiently to tissues.

6 Marks Q29. Explain the differences among blood, lymph, arteries, veins and capillaries.

Structure	Main Function
Blood	Transport of gases, nutrients, hormones and wastes
Lymph	Fluid balance, immunity and fat transport
Arteries	Carry blood away from heart
Veins	Carry blood towards heart
Capillaries	Exchange of substances with tissues

6 Marks Q30. Explain the complete mechanism of human circulation.

Answer:
Deoxygenated blood from body enters the right atrium through vena cava. It passes into the right ventricle and is pumped to lungs through pulmonary artery. In lungs, carbon dioxide is removed and oxygen is taken up. Oxygenated blood returns through pulmonary veins to the left atrium. It enters the left ventricle and is pumped through the aorta to the entire body. At tissue capillaries, oxygen and nutrients are supplied and wastes are collected. Deoxygenated blood then returns to the heart through veins.

33. HOTS / Application Based Questions

HOTS 1: Why does the pulmonary artery carry deoxygenated blood although it is an artery?

Answer: Artery is defined by direction of blood flow—away from the heart—not by oxygen content. Pulmonary artery carries blood away from the right ventricle to lungs.

HOTS 2: Why is the left ventricle more muscular than the right ventricle?

Answer: It has to pump blood over a much larger distance to the entire body, requiring greater pressure.

HOTS 3: What would happen if heart valves did not function properly?

Answer: Blood could flow backward, reducing the efficiency of circulation and increasing the workload on the heart.

HOTS 4: Why are capillary walls only one cell thick?

Answer: Thin walls provide a short diffusion distance, allowing rapid exchange of gases, nutrients and wastes.

34. Quick Revision – एक नजर में

🩸 Blood = Plasma + RBC + WBC + Platelets

🫀 Heart = 4 Chambers

🔵 Right Heart → Lungs

🔴 Left Heart → Body

Pulmonary Artery = Deoxygenated Blood

Pulmonary Vein = Oxygenated Blood

Aorta = Left Ventricle → Body

Vena Cava = Body → Right Atrium

Humans = Double Circulation

⭐ Exam Mantra:

Right side → Deoxygenated blood → Lungs
Left side → Oxygenated blood → Body

इसे याद रखने से Human Circulatory System के अधिकांश CBSE questions आसानी से हल किए जा सकते हैं।

Class 10th Science Chapter 5 – Life Processes | Transportation in Plants and Transpiration

Life Processes – Transportation in Plants

Class 10 Science | Transportation in Plants and Transpiration | CBSE + Foundation + Competitive

Transportation in Plants and Transpiration

1. Plants में Transportation क्यों आवश्यक है?

English:
Plants need a transport system to move water, minerals and food from one part of the plant to another.

हिन्दी:
पौधों को जल, खनिज लवण तथा भोजन को एक स्थान से दूसरे स्थान तक पहुँचाने के लिए परिवहन तंत्र की आवश्यकता होती है।

Plants में मुख्य transport tissues हैं:

• Xylem – water and minerals का transport
• Phloem – food का transport

2. 🌱 Animated Plant Transportation Diagram

Xylem, Phloem & Transpiration – Animated Flow

🔵 Blue animated particles: Xylem द्वारा water + minerals का upward movement.
🟠 Orange animated particles: Phloem द्वारा food का translocation.
💧 Water vapour: Stomata के माध्यम से transpiration.

3. Xylem | जाइलम

Xylem एक vascular tissue है जो मुख्य रूप से roots से stems और leaves तक water तथा dissolved minerals का transport करता है।

Direction:

Roots → Stem → Leaves

Xylem के प्रमुख components:

• Tracheids
• Vessels
• Xylem parenchyma
• Xylem fibres

Class 10 level पर मुख्य बात: Xylem → Water + Minerals

4. Roots द्वारा Water का Absorption

Roots में उपस्थित root hairs soil से water absorption में महत्वपूर्ण भूमिका निभाते हैं। Root hair की surface area अधिक होने के कारण soil के साथ contact बढ़ जाता है। Water सामान्यतः osmosis द्वारा root hair cells में प्रवेश करता है।

Soil → Root Hair → Root Cells → Xylem

5. Mineral Absorption

Plants को growth और metabolism के लिए mineral ions की आवश्यकता होती है। कुछ mineral ions roots द्वारा active transport की सहायता से भी absorb किए जा सकते हैं। इस प्रक्रिया में cellular energy का उपयोग हो सकता है।

6. Xylem में Water ऊपर कैसे पहुँचता है?

Water को roots से leaves तक पहुँचाने में कई forces योगदान देती हैं। मुख्य रूप से:

• Root pressure
• Transpiration pull
• Cohesion between water molecules
• Adhesion with xylem walls

Class 10 में transpiration pull को विशेष महत्व दिया जाता है।

7. Transpiration क्या है?

English:
Transpiration is the loss of water in the form of water vapour from the aerial parts of plants, mainly through stomata.

हिन्दी:
वाष्पोत्सर्जन (Transpiration) पौधे के वायवीय भागों, विशेषकर पत्तियों, से जल का water vapour के रूप में बाहर निकलना है।

Water in Leaf → Water Vapour → Atmosphere

8. Stomata | रंध्र

Stomata leaves की epidermis पर उपस्थित छोटे pores होते हैं। इनके चारों ओर guard cells होती हैं। Stomata के मुख्य कार्य:

• Gas exchange
• Transpiration
• CO₂ का प्रवेश
• O₂ का बाहर निकलना

9. Guard Cells की भूमिका

Guard cells stomatal pore को open और close करने में सहायता करती हैं। जब guard cells में water uptake होता है तो वे अधिक turgid होकर stomatal pore को खोल सकती हैं। Water loss और environmental conditions के अनुसार stomata की opening बदल सकती है।

10. Transpiration Pull

Leaves से water vapour के रूप में water loss होने पर leaf में water की कमी होती है। इससे xylem में water column पर upward pull उत्पन्न होता है। Water molecules में cohesion के कारण continuous water column बनाए रखने में सहायता मिलती है।

Transpiration → Water Loss → Transpiration Pull → Water Upward

11. Factors Affecting Transpiration

Factor	Effect
Temperature	Higher temperature generally increases transpiration.
Humidity	High humidity generally decreases transpiration.
Wind Speed	Higher wind speed generally increases transpiration.
Light	Light generally promotes stomatal opening and increases transpiration.
Water availability	Low water availability can reduce transpiration due to stomatal closure.

12. Transpiration का महत्व

1. Cooling

Water evaporation plants को cooling effect देती है।

2. Transpiration Pull

Water को roots से ऊपर खींचने में सहायता करता है।

3. Mineral Transport

Water movement के साथ dissolved minerals ऊपर पहुँचते हैं।

4. Water Movement

Plant के अंदर continuous water movement बनाए रखने में सहायता करता है।

13. Phloem | फ्लोएम

Phloem vascular tissue है जो leaves में बने food को plant के विभिन्न parts तक पहुँचाता है।

Source → Phloem → Sink

Source: जहाँ food बनता या उपलब्ध होता है, जैसे mature leaves.
Sink: जहाँ food की आवश्यकता या storage होती है, जैसे roots, fruits, seeds और growing tissues.

14. Translocation क्या है?

Phloem द्वारा food का plant के एक भाग से दूसरे भाग तक transport translocation कहलाता है। Phloem में transport केवल ऊपर की ओर ही नहीं होता। यह source और sink की आवश्यकता के अनुसार विभिन्न दिशाओं में हो सकता है।

Food → Phloem → Growing / Storage Parts

15. Phloem Transport में Energy की भूमिका

Phloem द्वारा food translocation में energy की आवश्यकता हो सकती है। Sucrose जैसे food पदार्थ को phloem tissue में loading के दौरान energy का उपयोग किया जा सकता है। इससे source और sink के बीच pressure gradient बनाने में सहायता मिलती है।

16. Xylem और Phloem में अंतर

Basis	Xylem	Phloem
Transport	Water and minerals	Food
Direction	Mainly upward	Source to sink; can be in different directions
Main function	Water/mineral conduction	Food translocation
Energy requirement	Transport mainly driven by physical forces such as transpiration pull	Active loading and translocation involve energy

17. Root Pressure | मूल दाब

Root pressure वह positive pressure है जो roots में विकसित होकर xylem में water को ऊपर की ओर push करने में सहायता कर सकता है। यह कुछ परिस्थितियों में water movement में योगदान देता है। लेकिन tall plants में water को बहुत अधिक ऊँचाई तक पहुँचाने के लिए root pressure अकेला पर्याप्त नहीं माना जाता।

18. Cohesion और Adhesion

Cohesion:
Water molecules का एक-दूसरे से आकर्षण।

Adhesion:
Water molecules का xylem walls से आकर्षण।

इन दोनों forces से xylem में continuous water column बनाए रखने में सहायता मिलती है।

19. Activity – Transpiration को Demonstrate करना

एक healthy plant की leafy twig को transparent polythene bag से cover किया जा सकता है। कुछ समय बाद bag की inner surface पर water droplets दिखाई दे सकते हैं। Conclusion: ये droplets leaves से निकले water vapour के condensation से बनते हैं। इससे transpiration को demonstrate किया जा सकता है।

⚠️ Experiment में plant को damage किए बिना सुरक्षित तरीके से activity करें। Transparent bag को leaves के ऊपर इस तरह बाँधें कि observations clearly दिखाई दें।

20. Complete Transportation Flow

Soil Water ↓ Root Hairs ↓ Root Cells ↓ Xylem ↓ Stem ↓ Leaves

Leaves में बने Food ↓ Phloem ↓ Roots / Fruits / Seeds / Growing Parts

Leaf Water ↓ Stomata ↓ Water Vapour ↓ Atmosphere

21. MCQs – Multiple Choice Questions

Question 1. Which tissue transports water in plants?

A) Xylem

B) Phloem

C) Epidermis

D) Cortex

Answer: A

Question 2. Food is transported through:

A) Xylem

B) Phloem

C) Root hair

D) Stomata

Answer: B

Question 3. Loss of water vapour from aerial parts of plants is called:

A) Respiration

B) Photosynthesis

C) Transpiration

D) Translocation

Answer: C

Question 4. Transpiration mainly occurs through:

A) Roots

B) Flowers

C) Fruits

D) Stomata

Answer: D

Question 5. Water is absorbed from soil mainly by:

A) Root hairs

B) Flowers

C) Fruits

D) Seeds

Answer: A

Question 6. Water enters root hair cells mainly by:

A) Diffusion of food

B) Osmosis

C) Photosynthesis

D) Translocation

Answer: B

Question 7. The upward movement of water in tall plants is strongly associated with:

A) Transpiration pull

B) Digestion

C) Fermentation

D) Germination

Answer: A

Question 8. Which cells regulate stomatal opening?

A) Xylem cells

B) Guard cells

C) Root cells

D) Phloem fibres

Answer: B

Question 9. Phloem transports mainly:

A) Water

B) Oxygen

C) Food

D) Carbon dioxide

Answer: C

Question 10. Food transport through phloem is called:

A) Transpiration

B) Translocation

C) Osmosis

D) Diffusion

Answer: B

Question 11. The source of food in a plant is commonly:

A) Mature leaf

B) Root hair

C) Xylem vessel

D) Stoma only

Answer: A

Question 12. A sink in a plant may be:

A) Only a leaf

B) Only a stoma

C) Root or fruit

D) Only xylem

Answer: C

Question 13. Which process helps cool a plant?

A) Transpiration

B) Digestion

C) Germination

D) Fermentation

Answer: A

Question 14. Which condition generally increases transpiration?

A) High humidity

B) Higher temperature

C) No leaves

D) Complete darkness

Answer: B

Question 15. High humidity generally:

A) Increases transpiration

B) Decreases transpiration

C) Stops photosynthesis completely

D) Increases root pressure only

Answer: B

Question 16. Water molecules attract each other due to:

A) Cohesion

B) Translocation

C) Respiration

D) Photosynthesis

Answer: A

Question 17. Attraction between water and xylem walls is called:

A) Cohesion

B) Adhesion

C) Osmosis

D) Fermentation

Answer: B

Question 18. Which tissue is a vascular tissue?

A) Xylem

B) Cuticle

C) Epidermal hair

D) Stoma

Answer: A

Question 19. Which tissue can transport food in different directions according to source and sink?

A) Xylem

B) Phloem

C) Epidermis

D) Root hair

Answer: B

Question 20. Root pressure is:

A) Positive pressure developed in roots

B) Pressure inside leaves only

C) Pressure caused by wind

D) Pressure in stomata

Answer: A

Question 21. Which tissue transports dissolved minerals along with water?

A) Phloem

B) Xylem

C) Epidermis

D) Guard cells

Answer: B

Question 22. Transpiration occurs mainly from:

A) Leaves

B) Roots

C) Seeds

D) Fruits only

Answer: A

Question 23. Which structure controls the opening and closing of stomata?

A) Xylem

B) Guard cells

C) Phloem

D) Root hairs

Answer: B

Question 24. Which process transports sugars from leaves?

A) Translocation

B) Transpiration

C) Osmosis

D) Diffusion only

Answer: A

Question 25. A major driving force for upward water movement in tall plants is:

A) Transpiration pull

B) Food pressure

C) Photosynthesis

D) Seed germination

Answer: A

Question 26. Which tissue contains sieve tubes?

A) Xylem

B) Phloem

C) Epidermis

D) Cortex only

Answer: B

Question 27. Water vapour leaves a leaf mainly through:

A) Stomata

B) Xylem

C) Phloem

D) Root hairs

Answer: A

Question 28. Which one is NOT a function of transpiration?

A) Cooling

B) Helping upward water movement

C) Direct synthesis of glucose

D) Contributing to mineral transport

Answer: C

Question 29. The movement of food through phloem requires:

A) Energy in loading and related processes

B) No cellular activity

C) Only sunlight

D) Only root pressure

Answer: A

Question 30. Which statement is correct?

A) Xylem transports only food.

B) Phloem transports only water.

C) Xylem transports water and minerals.

D) Transpiration occurs only in roots.

Answer: C

22. Subjective Questions – 1 to 6 Marks

1 Mark
Question 1. Name the tissue that transports water in plants.

Answer: Xylem.

1 Mark
Question 2. Name the tissue that transports food.

Answer: Phloem.

1 Mark
Question 3. Define transpiration.

Answer: Loss of water in the form of water vapour from aerial parts of plants, mainly through stomata, is called transpiration.

1 Mark
Question 4. What are stomata?

Answer: Stomata are tiny pores present mainly on the epidermis of leaves through which gas exchange and transpiration occur.

2 Marks
Question 5. What is the function of xylem?

Answer: Xylem transports water and dissolved minerals mainly from roots towards the stem and leaves.

2 Marks
Question 6. What is translocation?

Answer: Translocation is the transport of food, mainly sugars, through phloem from source tissues to sink tissues.

2 Marks
Question 7. What is the role of root hairs?

Answer: Root hairs increase the surface area of roots and help absorb water and mineral ions from the soil.

2 Marks
Question 8. Name two factors affecting transpiration.

Answer: Temperature and humidity. Other factors include wind speed and light.

3 Marks
Question 9. Explain the role of stomata in plants.

Answer: Stomata help in:

• Exchange of gases.
• Entry of carbon dioxide for photosynthesis.
• Loss of water vapour during transpiration.

3 Marks
Question 10. What is transpiration pull?

Answer: Loss of water from leaves creates a pulling force in the xylem. This force helps draw water upward from roots towards leaves and is called transpiration pull.

3 Marks
Question 11. Differentiate between xylem and phloem.

Xylem	Phloem
Transports water and minerals.	Transports food.
Movement is mainly upward.	Movement can occur in different directions.
Transpiration pull is an important driving force.	Food translocation involves energy-dependent loading.

3 Marks
Question 12. Explain the role of transpiration in plants.

Answer: Transpiration helps in cooling the plant, creates transpiration pull for upward movement of water and contributes to the transport of dissolved minerals.

4 Marks
Question 13. Explain how water moves from roots to leaves.

Answer: Water is absorbed by root hairs and enters the root tissues. It reaches xylem and moves upward through the stem. Evaporation of water from leaves creates transpiration pull, while cohesion and adhesion help maintain the water column.

4 Marks
Question 14. Explain the mechanism of transpiration.

Answer: Water reaches leaves through xylem. It evaporates from moist leaf surfaces and exits mainly through stomata as water vapour. This water loss creates a water potential gradient and contributes to transpiration pull.

4 Marks
Question 15. What is the role of phloem in plants?

Answer: Phloem transports food such as sucrose from source tissues, mainly leaves, to sink tissues such as roots, fruits, seeds and growing regions. Loading and transport processes involve energy.

4 Marks
Question 16. Explain source and sink in phloem transport.

Answer: The source is the part where food is produced or available in excess, commonly mature leaves. The sink is the part where food is required or stored, such as roots, fruits, seeds and growing tissues. Phloem transports food from source to sink.

5 Marks
Question 17. Describe the transportation of water and minerals in plants.

Answer: Water and minerals are absorbed from soil by roots. Root hairs provide a large absorbing surface. Water enters root tissues and reaches xylem. Xylem carries water and minerals upward through the stem to leaves. Transpiration from leaves generates a pull that contributes significantly to upward water movement.

5 Marks
Question 18. Explain the importance of transpiration.

Answer: Transpiration:

• Helps cool the plant.
• Creates transpiration pull.
• Assists upward movement of water.
• Helps transport dissolved minerals.
• Maintains continuous movement of water through the plant.

5 Marks
Question 19. Explain transportation of food through phloem.

Answer: Food produced in leaves is converted into transportable sugars such as sucrose. These sugars are loaded into phloem. Energy is involved in loading and related processes. The resulting pressure gradient helps move phloem sap from source regions to sink regions where food is used or stored.

6 Marks
Question 20. Explain the complete transport system in plants.

Water and Minerals:

Soil → Root Hair → Root → Xylem → Stem → Leaves

Food:

Leaves → Phloem → Roots / Fruits / Seeds / Growing Parts

Xylem mainly carries water and minerals upward, while phloem transports food from source to sink.

6 Marks
Question 21. Explain transpiration pull, cohesion and adhesion in water transport.

Answer: Water evaporates from leaf surfaces through stomata. This creates a pull in the xylem called transpiration pull. Cohesion between water molecules helps maintain a continuous water column. Adhesion between water and xylem walls also supports the movement of water. Together these forces help transport water from roots to leaves.

6 Marks
Question 22. Explain the factors affecting transpiration.

• Temperature: Higher temperature generally increases evaporation and transpiration.
• Humidity: High humidity decreases the water vapour gradient and generally reduces transpiration.
• Wind: Wind removes humid air around leaves and can increase transpiration.
• Light: Light generally promotes stomatal opening and therefore can increase transpiration.
• Water availability: Water shortage can lead to stomatal closure and reduce transpiration.

3 Marks
Question 23. Why is transpiration called a necessary evil?

Answer: Transpiration causes loss of water, so it can be harmful when excessive. However, it also provides important benefits such as cooling and creating transpiration pull for water movement. Therefore, it has been traditionally described as a necessary evil.

4 Marks
Question 24. Why is root pressure alone not sufficient to transport water to the top of a tall tree?

Answer: Root pressure can contribute to upward movement of water but is generally not strong enough to lift water to the great heights of tall trees. Transpiration pull, supported by cohesion and adhesion, plays a major role in long-distance water transport.

2 Marks
Question 25. What happens to transpiration when humidity increases?

Answer: Transpiration generally decreases because the difference in water vapour concentration between leaf air spaces and the atmosphere becomes smaller.

3 Marks
Question 26. Why do plants need vascular tissues?

Answer: Vascular tissues allow long-distance transport of water, minerals and food. Xylem transports water and minerals, while phloem transports food.

5 Marks
Question 27. Describe an activity to demonstrate transpiration.

Answer: Cover the leafy portion of a healthy plant with a transparent polythene bag and tie it properly. After some time, water droplets appear on the inner surface of the bag. These droplets arise from water vapour released by leaves and subsequently condensed. This demonstrates transpiration.

5 Marks
Question 28. Explain how stomata regulate water loss.

Answer: Stomata are surrounded by guard cells. When guard cells become turgid, the stomatal pore generally opens; when they lose water and become less turgid, the pore tends to close. Thus, stomata regulate gas exchange and water loss.

6 Marks
Question 29. Compare water transport and food transport in plants.

Feature	Water Transport	Food Transport
Tissue	Xylem	Phloem
Material	Water + minerals	Food/sugars
Direction	Mainly upward	Source to sink, potentially in different directions
Driving factors	Transpiration pull, cohesion, adhesion, root pressure contribution	Pressure flow associated with phloem loading and unloading

6 Marks
Question 30. Explain transportation in plants with a suitable flow diagram.

Water and Minerals:

SOIL ↓ ROOT HAIRS ↓ ROOT ↓ XYLEM ↓ STEM ↓ LEAVES

Food:

LEAVES ↓ PHLOEM ↓ ROOTS / FRUITS / SEEDS / GROWING PARTS

Transpiration:

LEAF WATER ↓ STOMATA ↓ WATER VAPOUR ↓ ATMOSPHERE

23. HOTS / Competency Based Questions

HOTS 1. Why does transpiration generally increase on a hot and dry day?

Answer: High temperature increases evaporation, while low humidity creates a larger water vapour gradient between the leaf and atmosphere. Therefore transpiration generally increases.

HOTS 2. Why may a plant wilt when soil water is insufficient?

Answer: When water absorption cannot compensate for water loss, cells lose turgidity and the plant may wilt. Stomatal closure can reduce further water loss.

HOTS 3. Why is xylem transport mainly upward?

Answer: Water absorbed by roots is transported toward aerial parts, especially leaves, where it is used and lost through transpiration. Transpiration pull strongly supports upward xylem movement.

HOTS 4. A plant is kept in a humid chamber. What happens to transpiration?

Answer: Transpiration generally decreases because the surrounding air already contains more water vapour, reducing the diffusion gradient.

24. CBSE Exam Golden Points ⭐

• Xylem → Water + Minerals.
• Phloem → Food.
• Root hairs absorb water and minerals.
• Water enters roots mainly through osmosis.
• Transpiration = loss of water vapour from aerial parts.
• Stomata are the major sites of transpiration.
• Guard cells regulate stomatal opening.
• Transpiration pull helps water move upward.
• Cohesion keeps water molecules together.
• Adhesion helps water interact with xylem walls.
• Phloem transport is called translocation.
• Food moves from source to sink.
• Transpiration helps cool plants.

25. One-Minute Revision

ROOTS → XYLEM → STEM → LEAVES

Water + Minerals ↑

LEAVES → PHLOEM → SINK

Food ↓ / → according to source-sink requirement

LEAF WATER → STOMATA → WATER VAPOUR

Transpiration → Transpiration Pull → Upward Water Movement