Transportation in Animals and Plants – Class 7 Science (Notes + Q&A)

This chapter explains how living organisms move essential materials within their bodies. In animals, fluids like blood transport oxygen, nutrients, and helpful substances to cells and carry waste away. In plants, specialized tissues move water, minerals, and prepared food between roots, stems, and leaves. The notes below are concise, student-friendly, and aligned with NCERT. After the notes, you will find a complete set of exam-oriented questions: 7 MCQs (with choices), 7 Very Short, 7 Short, and 7 Long Answers. Use the jump buttons above to navigate quickly.

A. Easy Notes – Transportation in Animals and Plants

1) Why Transportation Is Needed

Every cell needs a steady supply of oxygen and nutrients and must also send out waste products for removal. Transportation systems ensure timely delivery and removal. In complex animals, a circulatory system handles this efficiently. In plants, different pathways move water, minerals, and prepared food to various parts.

Exam Tip: Remember three main flows: (i) oxygen/nutrients to cells, (ii) waste away from cells, (iii) in plants—water/minerals upwards (xylem) and food to all parts (phloem).

2) Transportation in Animals (Humans as a Model)

The human circulatory system includes the heart, blood, and blood vessels. Blood is a fluid connective tissue that flows through a network of tubes to reach every cell.

3) Blood and Its Components

Plasma is the liquid part that carries dissolved substances such as glucose, amino acids, vitamins, hormones, and waste like urea. Red blood corpuscles (RBCs) contain hemoglobin which helps in carrying oxygen from the lungs to tissues. White blood corpuscles (WBCs) help the body stay protected. Platelets assist in clot formation when there is a cut on the skin so that excessive fluid loss does not occur.

4) Blood Vessels: Arteries, Veins, and Capillaries

Arteries usually carry oxygen-rich blood away from the heart to body parts. Their walls are thick and elastic to handle the pressure of the blood pumped by the heart. Veins typically return oxygen-low blood back to the heart and have thinner walls; many contain valves that ensure one-way flow. Capillaries are very thin, tiny vessels connecting arteries to veins; exchange of materials between blood and tissues mainly occurs here.

Remember: Artery = away from heart; vein = toward heart; capillary = exchange surface.

5) The Heart and Circulation

The human heart has four chambers: right atrium and right ventricle (receive and send oxygen-low blood toward lungs), left atrium and left ventricle (receive oxygen-rich blood from lungs and pump it to the body). Valves ensure one-directional flow. The heart functions like a coordinated pump with rhythmic contractions.

6) Heartbeat and Pulse

When the heart contracts and relaxes, pressure changes occur in arteries. This rhythmic expansion and contraction in an artery (commonly felt at the wrist) is called the pulse. Counting pulse gives the heart rate. During activity, the rate increases to meet higher demand for oxygen and nutrients. In a calm state, the rate stays lower.

7) Excretion – Removal of Waste Materials

The body must remove dissolved wastes. In humans, the excretory system includes two kidneys, ureters, urinary bladder, and urethra. Kidneys filter blood to remove urea and other dissolved wastes, forming urine which is stored in the bladder and released periodically.

Healthy Habit Box: Adequate water intake supports kidney function. Balanced diet and regular activity help the overall transport and removal processes in the body.

8) Transportation in Plants – Overview

Plants absorb water and minerals from the soil through root hairs. Two specialized tissues manage transport: xylem carries water and minerals (mostly upward from roots to stems and leaves), and phloem transports prepared food (sugars) from leaves to non-green parts like roots, fruits, and developing tissues.

9) Absorption by Roots

Root hairs increase surface area to absorb water by osmosis and minerals by active uptake. The absorbed water moves from cell to cell toward xylem vessels. From there, water ascends due to a combination of root pressure, capillary action, and pulling force generated by transpiration at the leaf surface.

10) Xylem and Phloem

Xylem is made of vessels, tracheids, xylem parenchyma, and fibers. Vessels act like long tubes that conduct water efficiently. Phloem contains sieve tubes, companion cells, phloem parenchyma, and fibers; it transports food from leaves to all parts including storage organs. This flow can be in many directions depending on need.

11) Transpiration and Its Role

Transpiration is the loss of water as water vapor through tiny openings called stomata, mainly on leaves. Besides cooling the leaf surface, transpiration helps create a suction force that pulls water upward through the xylem (transpiration pull). It also maintains movement of minerals and keeps cells turgid (firm).

Concept Link: Photosynthesis needs water; water reaches leaves via xylem. Food made in leaves moves via phloem to parts that cannot make their own food.

12) Diffusion and Osmosis (Simple View)

Diffusion is the movement of particles from a region of higher concentration to lower concentration (for example, fragrance moving across a room). Osmosis is the movement of water through a selectively permeable membrane from higher water concentration to lower water concentration. Plants use osmosis for absorption and maintaining cell firmness.

B. Questions & Answers – Transportation in Animals and Plants

1) Multiple Choice Questions (7) – Choose the correct option

Q1. The main function of platelets is to:
A) Carry oxygen    B) Help in blood clotting    C) Fight infections    D) Carry food
Answer: B) Help in blood clotting. Platelets form a temporary plug and support clot formation.

Q2. Which vessels usually carry blood away from the heart?
A) Veins    B) Capillaries    C) Arteries    D) Lymph vessels
Answer: C) Arteries. They typically transport blood from the heart to body parts.

Q3. Pulse is felt due to the rhythmic expansion of:
A) Veins    B) Arteries    C) Capillaries    D) Heart chambers
Answer: B) Arteries. Arterial walls expand and relax with each heartbeat.

Q4. In plants, upward movement of water and minerals is primarily through:
A) Phloem    B) Xylem    C) Cortex    D) Epidermis
Answer: B) Xylem. Xylem vessels conduct water and minerals from roots to leaves.

Q5. Loss of water as vapor from leaves is called:
A) Translocation    B) Transpiration    C) Respiration    D) Germination
Answer: B) Transpiration. It occurs mainly through stomata.

Q6. Food prepared in leaves moves to other parts through:
A) Xylem    B) Phloem    C) Stomata    D) Pith
Answer: B) Phloem. Sieve tubes transport sugars to storage and growing regions.

Q7. The organ that filters blood and forms urine is:
A) Lungs    B) Heart    C) Kidneys    D) Intestine
Answer: C) Kidneys. They remove dissolved wastes and maintain fluid balance.

2) Very Short Answer Questions (7) – 1–2 lines

Q1. What is the function of hemoglobin in RBCs?
Ans: Hemoglobin binds oxygen in the lungs and carries it to body tissues.

Q2. Define pulse.
Ans: Pulse is the regular expansion and contraction of an artery due to heartbeats.

Q3. Name the two main transport tissues in plants.
Ans: Xylem (water and minerals) and Phloem (prepared food).

Q4. What is transpiration?
Ans: The release of water vapor from leaf surfaces, mainly through stomata.

Q5. List the parts of the human excretory system.
Ans: Kidneys, ureters, urinary bladder, and urethra.

Q6. What is the role of valves in veins?
Ans: Valves ensure one-way flow of blood toward the heart.

Q7. Where are root hairs located and what is their role?
Ans: On young roots; they absorb water and minerals from the soil.

3) Short Answer Questions (7) – about 40–60 words each

Q1. Differentiate between arteries and veins.
Ans: Arteries usually carry oxygen-rich blood away from the heart and have thick, elastic walls to manage pressure. Veins generally return oxygen-low blood to the heart, have thinner walls, and possess valves to maintain one-way flow. Both are essential for continuous circulation with capillaries connecting their pathways.

Q2. State the components of blood and their functions in brief.
Ans: Blood has plasma, RBCs, WBCs, and platelets. Plasma transports dissolved substances. RBCs carry oxygen through hemoglobin. WBCs help the body stay protected. Platelets assist in clot formation, limiting loss of blood and allowing healing to begin.

Q3. What is excretion? Name the main excretory product removed by kidneys.
Ans: Excretion is the process of removing metabolic wastes from the body. Kidneys filter blood and remove urea along with other dissolved wastes, forming urine that is stored in the bladder and released at suitable intervals.

Q4. How does water reach the leaves from the soil?
Ans: Root hairs absorb water which moves to xylem through root tissues. Xylem vessels transport water upward via root pressure, capillary action, and transpiration pull. This coordinated movement delivers water to stems and leaves for various functions, including photosynthesis.

Q5. Define diffusion and osmosis with simple examples.
Ans: Diffusion is movement from higher to lower concentration, like fragrance spreading in a room. Osmosis is movement of water through a selectively permeable membrane from higher water concentration to lower, such as water entering a raisin placed in plain water.

Q6. What is the role of transpiration in plants?
Ans: Transpiration removes excess water as vapor, cools leaf surfaces, and generates a pull that assists upward movement of water and minerals through xylem. It also maintains turgor in cells and supports nutrient distribution.

Q7. Explain why pulse rate increases during brisk activity.
Ans: During activity, cells use more oxygen and nutrients and produce more waste. The heart pumps faster to supply increased demand and to remove wastes efficiently, which increases arterial expansion and hence the pulse rate.

4) Long Answer Questions (7) – about 120–150 words each

Q1. Describe the human heart and the path of blood through its chambers.
Ans: The heart has four chambers: right atrium and right ventricle on one side, and left atrium and left ventricle on the other. Oxygen-low blood from the body enters the right atrium, passes to the right ventricle, and is sent to the lungs for oxygenation. Oxygen-rich blood returns to the left atrium, moves to the left ventricle, and is pumped through the aorta to the body. Valves between chambers ensure one-way flow and prevent backflow. Coordinated contractions (heartbeats) maintain continuous circulation, supplying tissues with oxygen and nutrients while transporting wastes away for removal.

Q2. Explain the roles of RBCs, WBCs, platelets, and plasma in maintaining health.
Ans: Plasma is the liquid medium that carries nutrients, hormones, and wastes. RBCs contain hemoglobin which binds oxygen in the lungs and releases it to tissues, supporting energy processes. WBCs help keep the body protected through several mechanisms. Platelets, together with clotting factors, form a clot when there is a cut on the skin, minimizing fluid loss. The combined action of these components keeps the internal environment stable and suitable for proper functioning.

Q3. Discuss the structure and function of xylem and phloem in plants.
Ans: Xylem consists mainly of vessels and tracheids that form long tubes for conducting water and minerals from roots to leaves. Their thick, lignified walls provide support as well. Phloem is composed of sieve tubes and companion cells that move prepared food (sugars) from leaves to growing and storage regions. Unlike xylem flow which is mainly upward, phloem transport (translocation) can be in several directions based on need. Together, xylem and phloem form a continuous network, ensuring resource delivery to every part of the plant.

Q4. What is transpiration pull? How does it support water movement in tall plants?
Ans: When water evaporates through stomata, it creates a tiny suction at the leaf surface. This suction pulls a continuous column of water upward through xylem vessels—a process called transpiration pull. Because water molecules stick to each other (cohesion) and to the tube walls (adhesion), the column remains unbroken. In tall plants, transpiration pull provides a strong, steady force that lifts water and dissolved minerals from roots to great heights without a mechanical pump.

Q5. How do kidneys filter blood and help maintain balance in the body?
Ans: Kidneys contain millions of tiny filtering units that remove dissolved wastes like urea along with excess water and salts. The useful substances are reabsorbed back into the blood, while wastes form urine. By adjusting the reabsorption of water and salts, kidneys help maintain fluid and mineral balance. The urine flows through ureters to the bladder for temporary storage and is released through the urethra when the body is ready.

Q6. Compare transportation in animals and plants under three headings: medium, pathways, and driving force.
Ans: In animals, the medium is blood; the pathways are arteries, veins, and capillaries; the driving force is the heart’s pumping. In plants, the media include water/minerals and prepared food; pathways are xylem and phloem; and the driving forces are root pressure, capillarity, and transpiration pull for xylem, while phloem movement relies on pressure differences generated by loading and unloading of sugars. Both systems ensure that every cell receives what it needs and that wastes or excess materials are moved away.

Q7. A leaf performs photosynthesis yet still needs a steady water supply and a way to distribute food. Explain the coordination between xylem and phloem in a leaf.
Ans: Water enters leaves through xylem and is used in photosynthesis and to maintain cell turgor. As photosynthesis produces sugars in the leaf mesophyll, these sugars are loaded into phloem sieve tubes. The resulting pressure difference drives the sugars toward growing regions, roots, and storage organs. Meanwhile, water lost by transpiration is replaced through xylem. Thus, xylem supports photosynthesis by supplying water, and phloem distributes the products of photosynthesis to the rest of the plant, creating a coordinated transport network.

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