GSEB Class 7 Science Solutions Chapter 11 પ્રાણીઓ અને વનસ્પતિઓમાં વહન

Textbook Exercise Questions and Answers

Question. Match the details given in Column I with Column II:

Answer: (1) → (b), (2) → (d), (3) → (a), (4) → (c).
In simple words: This matching exercise connects plant parts to their main functions. Stomata are involved in transpiration, xylem tissue carries water, root hair takes in water, and phloem tissue moves food.

Exam Tip: Remember the primary roles of different plant structures and tissues for effective matching questions. Stomata handle gas exchange and water release, xylem transports water, phloem moves food, and root hairs absorb water and minerals.

2. Fill in the Blanks

Question 1. Blood is transported from the heart to all parts of the body through ........ .
Answer: ધમનીઓ
In simple words: Blood leaves the heart and travels to the whole body using arteries.

Exam Tip: Understand the difference between arteries, veins, and capillaries and their specific roles in blood circulation.

Question 2. Hemoglobin is found in the ........ cells of the blood.
Answer: રક્તકણો
In simple words: Red blood cells contain hemoglobin, which gives blood its color.

Exam Tip: Recall that hemoglobin is the protein in red blood cells responsible for carrying oxygen and giving blood its red color.

Question 3. Arteries and veins are connected by a network of ........ .
Answer: કેશિકાઓ
In simple words: Tiny blood vessels called capillaries link arteries and veins together.

Exam Tip: Capillaries are the smallest blood vessels, crucial for nutrient and waste exchange between blood and tissues.

Question 4. The rhythmic contraction and relaxation of the heart is called ........ .
Answer: હૃદયના ધબકારા
In simple words: Your heartbeat is the regular squeeze and release motion of your heart.

Exam Tip: A heartbeat involves both systole (contraction) and diastole (relaxation) phases, which ensure efficient blood pumping.

Question 5. In humans, ........ is the main excretory product.
Answer: યૂરિયા
In simple words: Urea is the primary waste material that humans' bodies get rid of.

Exam Tip: Urea is formed in the liver from ammonia and is excreted by the kidneys through urine.

Question 6. Sweat contains water and ........ .
Answer: ક્ષારો
In simple words: Sweat has water and also some salts mixed in it.

Exam Tip: Sweating helps in cooling the body and removing excess salts and other waste products.

Question 7. The kidney removes liquid waste from the body, which is called ........ .
Answer: મૂત્ર
In simple words: The liquid waste that kidneys remove from our body is called urine.

Exam Tip: Understand that urine is the liquid waste product formed by the kidneys during the filtration of blood.

Question 8. Transpiration pull is created by ........ due to which water can rise very high.
Answer: બાષ્પોત્સર્જન
In simple words: The upward pull of water in plants is created by transpiration.

Exam Tip: Transpiration pull is a key mechanism for water transport in tall plants, driven by the evaporation of water from leaves.

3. Choose the Correct Option

Question 1. Water is transported in plants through ........ .
(a) જલવાહક પેશી
(b) અન્નવાહક પેશી
(c) પર્ણરંદ્ર
(d) મૂળરોમ
Answer: (a) જલવાહક પેશી
In simple words: Plants move water around their bodies using xylem tissue.

Exam Tip: Remember that xylem is responsible for water transport, while phloem transports food in plants. Stomata are for gas exchange and transpiration, and root hairs absorb water.

Question 2. Water absorption in plants can be increased by keeping them ........ .
(a) છાંયડામાં
(b) આછા પ્રકાશમાં
(c) પંખા નીચે
(d) પૉલિથીન બેગથી ઢાંકીને
Answer: (c) પંખા નીચે
In simple words: Placing a plant under a fan helps it absorb more water by increasing transpiration.

Exam Tip: Increasing air movement (like with a fan) enhances transpiration, which in turn boosts water absorption by the roots.

Question 4. Why is the transport of substances necessary in plants and animals? Explain.
Answer: Plants and animals need food, water, and oxygen to stay alive. It is crucial to move these items from one part of the body to another. Waste materials created in plants and animals, also known as excretory products, must go to the parts where they can be removed from the body. To do all this, moving essential nutrients, oxygen, enzymes, hormones, and waste products from one place to where they are needed becomes important.
In simple words: Plants and animals need to move food, water, and oxygen to all their parts to live. They also need to move waste products out of their bodies. This transport system is vital for survival.

Exam Tip: When explaining the necessity of transport, focus on both the delivery of essential resources (food, water, oxygen) and the removal of metabolic wastes.

Question 5. What happens if there are no platelets in the blood?
Answer: The process of blood clotting depends on the platelets in the blood. If any part of our body gets hurt or cut, blood starts to flow. Platelets in the blood help the flowing blood clot, and the bleeding usually stops on its own after some time. If there were no platelets in the blood, the clotting process would not happen when you get hurt or wounded. As a result, all the blood would flow out of the body, which could be very dangerous and even deadly.
In simple words: Without platelets, blood cannot clot. If you get a cut, you would keep bleeding, which can be life-threatening.

Exam Tip: Emphasize the crucial role of platelets in hemostasis (stopping bleeding) to secure full marks for this question.

Question 6. What are stomata? Give two functions of stomata.
Answer: Tiny pores are present on the surface of plant leaves. These tiny openings are called stomata. These stomata are surrounded by special guard cells. The two main functions of stomata are as follows:
1. Through the stomata of plants, extra water is released from the plant as vapor through the process of transpiration.
2. During photosynthesis and respiration in plants, the exchange of gases (like carbon dioxide and oxygen) occurs through these stomata.
In simple words: Stomata are tiny holes on leaves. They help plants release extra water and breathe in and out gases like carbon dioxide and oxygen.

Exam Tip: Clearly define stomata and list their two main physiological functions: gas exchange and transpiration.

Question 7. Does transpiration play an important role in plants? Explain.
Answer: Yes, transpiration plays a very important role in plants. Through the process of transpiration in plants, any extra water is released. This process helps cool both the plants and their surrounding environment. When water evaporates as vapor through transpiration, it creates a "suction pull" or "transpiration pull." This pull helps water travel from the roots to very high parts of the plant, which is then used by the leaves for photosynthesis. The constant column of water that forms from the roots to the leaves offers the absorbing power needed for the movement of water and dissolved mineral salts to various parts of the plant from the soil. Therefore, transpiration plays a vital role in plants.
In simple words: Yes, transpiration is very important. It helps plants remove excess water, keeps them cool, and creates a pulling force that draws water and nutrients from the roots up to the leaves.

Exam Tip: When discussing transpiration's importance, highlight its roles in cooling, nutrient transport, and creating the necessary upward pull for water in tall plants.

Question 8. Name the different components of blood.
Answer: The components of blood are: blood plasma, red blood cells, white blood cells, and also platelets.
In simple words: Blood is made of four main parts: plasma, red blood cells, white blood cells, and platelets.

Exam Tip: Make sure to list all four major components of blood, as each has distinct functions essential for overall health.

Question 9. Why do all parts of the body need blood?
Answer: All parts of the body require blood for several reasons:
1. Blood contains important nutrients from food and oxygen, which give cells in all body parts the energy they need to work.
2. Blood transports waste products that are made in the body's parts and carries them to the excretory organs for removal.
3. Blood also has enzymes and hormones, which are chemicals that need to be carried to all the different parts of the body to perform their functions.
In simple words: Every part of the body needs blood because it delivers food and oxygen for energy, removes waste products, and carries important chemicals like hormones to where they are needed.

Exam Tip: Focus on blood's triple role: supply of essentials, removal of wastes, and transport of regulatory substances (enzymes/hormones).

Question 10. Why is blood red?
Answer: Red blood cells contain a red pigment called hemoglobin. Because hemoglobin is present in the blood, the color of blood is red.
In simple words: Blood looks red because red blood cells have a special red substance called hemoglobin.

Exam Tip: Directly state that hemoglobin is the pigment responsible for blood's red color and is found within red blood cells.

Question 11. Write the functions of the heart.
Answer: The heart is an organ that beats continuously and works like a pump, which moves blood and the substances found in it. Both the atria and then both ventricles contract and relax in a rhythmic way.
1. When the atria relax, deoxygenated (impure) blood containing carbon dioxide, collected from the body's organs, enters the right atrium through the major veins. At the same time, oxygenated (pure) blood from the lungs enters the left atrium through the pulmonary veins.
2. Now, when both atria contract, deoxygenated blood from the right atrium goes into the right ventricle, and oxygenated blood from the left atrium enters the left ventricle.
3. Next, when both ventricles contract, deoxygenated blood from the right ventricle goes to the lungs through the pulmonary artery, and oxygenated blood from the left ventricle goes to various parts of the body through the main artery.
Thus, the heart sends deoxygenated blood from the body parts to the lungs for cleaning. It then brings this cleaned, oxygenated blood back to the heart and forcefully sends the blood to different parts of the body.
In simple words: The heart pumps blood around the body. It sends deoxygenated blood to the lungs to get oxygen and then pumps the fresh, oxygenated blood to all other body parts.

Exam Tip: Clearly explain the two main circuits of blood flow (pulmonary and systemic) and how the heart's chambers coordinate to pump blood through them effectively.

Question 12. Why is it necessary to excrete waste products?
Answer: During the biological processes in the body, some useless and harmful toxic substances are created within the cells. These toxic substances produced in the body's cells are called excretory products. Excretory products are harmful and damaging to the body, so they must be removed from the body. Therefore, it is important to excrete these waste products from the body regularly.
In simple words: Our bodies make harmful waste products during daily functions. These wastes are toxic and must be removed to keep the body healthy.

Exam Tip: Emphasize that waste products are toxic and their accumulation can be detrimental to bodily functions, hence the necessity of excretion.

Question 13. Draw a labeled diagram of the human excretory system.
Answer:
[Figure: Diagram of the human excretory system, showing the right kidney, left kidney, ureters, urinary bladder, and urethra.]
In simple words: You need to draw a picture showing how the body cleans out waste liquids, including the two kidneys, the tubes connecting them to the bladder, and the tube that expels urine.

Exam Tip: Ensure all key organs (kidneys, ureters, bladder, urethra) are clearly drawn and correctly labeled in your diagram. Focus on anatomical accuracy.

Understanding Textbook Activities

Activity 1:

To find the pulse rate in humans in a resting state.

Method:

1. Place the index and middle fingers of your right hand on the inner side of your left wrist.

2. Try to feel the pulse beats there.

3. Count the number of pulse beats in one minute.

4. Count the number of pulse beats per minute of your classmates.

Record your observations in Table 11.1.

Table 11.1: Pulse Rate

Answer:
Conclusion: In a resting state, the human pulse rate is between 72 and 80 beats per minute.
In simple words: When resting, a person's pulse usually beats 72 to 80 times each minute.

Exam Tip: When conducting experiments, ensure accurate counting and clear recording of data in tables for valid conclusions.

Activity 2:

To make a simple stethoscope and measure heartbeats and pulse rate with it.

Materials: Funnel with 6-7 cm diameter, rubber tube.

[Figure: Sample of a stethoscope, showing a funnel connected to a rubber tube, with the other end of the tube placed near the ear and the funnel on the chest.]

Method:

1. Take a funnel with a diameter of 6 – 7 cm.

2. Attach a rubber tube (50 cm long) tightly to it.

3. Stretch the rubber tightly over the mouth of the funnel and tie it with rubber as shown in the figure (stethoscope sample).

4. Place one open end of the tube near your ear. Keep the wide part of the funnel near the heart on your chest. Listen carefully.

5. Count the heartbeats in one minute.

6. Run for 4-5 minutes and then count the heartbeats in one minute. Also, measure the pulse rate.

7. Measure the heartbeats and pulse rate of your classmates in the same way.

Record your observations in Table 11.2.

Table 11.2: Heartbeats and Pulse Rate

Answer:
Conclusion: The heart rate and pulse rate are almost similar. After running, the heart rate and pulse rate are higher than during a normal resting state.
In simple words: Your heart rate and pulse rate are very close. Both go up after exercise compared to when you are resting.

Exam Tip: Understand that physical activity increases both heart rate and pulse rate as the body demands more oxygen and nutrients.

Activity 3:

To demonstrate that the plant stem transports water and mineral salts solution.

Materials: Glass, a tender stem plant (with roots removed), blade, water, red ink.

[Figure: Diagram showing a tender stem plant (with roots cut) placed in a glass containing water mixed with red ink. The red-colored water is clearly visible, moving up into the stem.]

Method:

1. Take a glass.

2. Pour water into it until it's about one-third full.

3. Add a few drops of red ink to the water to make it red.

4. Take a plant with a tender stem and cut the stem near its base with a blade.

5. Place the plant in the glass filled with red water as shown in the figure.

6. Observe the stem and branches of the plant the next day.

Answer:
Observation: The stem and branches of the plant appear reddish.
Conclusion: The plant stem transports water and mineral salt solution.
In simple words: The plant's stem and branches turned red, showing that the stem carried the colored water upwards, meaning it transports water and minerals.

Exam Tip: This experiment visually demonstrates the function of xylem in water transport. The red color acts as a tracer to confirm the upward movement.