Solved examples for class 7 science : Chapter 11

    Transportation in Animals and Plants

    I. Multiple Choice Questions (MCQs).
    Q.1. A red pigment that plays a very important role in transport of oxygen from lungs to cells and carbon dioxide from cells to lungs, is ______________.

    a) red blood cells
    b) xanthophyll
    c) myoglobin
    d) haemoglobin
    Answer: (a) red blood cells

    Q.2. The cells that fight against the germs which enter our body, are ___________.
    a) red blood cells
    b) white blood cells
    c) platelets
    d) plasma

    Answer: (b) white blood cells

    Q.3. The blood vessels, which carry oxygen-rich blood from heart to all parts of the body, are called ______________.
    a) arteries
    b) veins
    c) capillaries
    d) all of these
    Answer: a) arteries
    Q.4. The blood vessels, which help to join the arteries and veins are
    a) atria
    b) capillaries
    c) platelets
    d) none of these
    Answer: b) capillaries
    Q.5. Which blood group is called the universal donor?
    a) A
    b) AB
    c) B
    d) O
    Answer d) O
    II. Fill in the blanks by selecting appropriate words from the given list :
    List : circulatory, pulmonary, metabolic, excretory, salt
    Q.1. Sweating removes water and ______________ from the body.
    Q.2. In human being, ______________ system is responsible for the removal of waste substances.
    Q.3. In the presence of oxygen, the cells perform many ______________ processes.
    Q.4. In human beings, ______________ system carries blood from heart to different parts of the body and brings it back to heart.
    Q.5. The ______________ vein carries O2 rich and CO2 deficient blood from lungs to heart.

    Ans: 1-salt, 2- excretory, 3- metabolic 4- circulatory 5- pulmonary III. Match the items of Column A with those of Column B.

    Answer: 1-(e), 2-(a), 3-(d), 4-(b ), 5-(c )

    IV. Write ‘T’ for the true and ‘F’ for the false statements.
    Q.1. Heart is associated with the circulatory system.
    Q.2. The left part of the heart is separated from the right part of the heart with the help of a ventricle.
    Q.3. Exercising, running and cycling increases the rate of heart beat.
    Q.4. Simple animals like Hydra and sponges also have proper circulatory systems.
    Q.5. In humans, urine is stored until the expansion of bladder leading to an urge to pass it out through the urethra.

    Answer: 1-T, 2-F, 3-T, 4-F, 5-T
    V. Very Short Answer Questions.
    Q.1. Where is human heart located?
    Answer: human heart is located in chest cavity with its Lower tip slightly tilted towards the Left.

    Q.2. Name the tissue responsible for the transport of food substances in plants.

    Answer: The food synthesised by the leaves is transported in a soluble form to all parts of the plant by vascular tissues called phloem.

    Q.3. Name the vein, which brings carbon dioxide rich blood from the whole body to the right artium.
    Answer: Vena cavaIa vein bring carbon dioxide rich blood from the whole body to the right artium.

    Q.4. Name the side of the heart in which oxygen-rich blood is found.

    Answer: Heart always contains oxygen-rich blood in its Left side.

    Q.5. How much blood is filtered in 24 hours in a human body?

    Answer: Approximately 180 litres of blood is filtered in 24 hours.

    VI. Short Answer Questions.
    Q.1. Define the circulatory system of human and write its components also.
    Answer: The circulatory system is a network of organs that provide circulation of blood. This system consists of heart, blood vessels and blood.

    Q.2. Define human excretory system and write its components also.
    Answer: The system that excretes wastes from the body is known as excretory system. Human excretory system consists of two kidneys, two ureters, one urinary bladder, and a urethra.
    Q.3. How is the transport of substances possible in plants?
    Answer: Plants have specialised tissues [group of cells] that help in transport of food, minerals and water. The tissues that help in transport of substances in plants are called vascular tissues. Plants contain two types of vascular tissues viz, xylem and phloem.

    Q.4. How does the circulation of blood occur in human body? Explain with suitable diagram.
    Answer: Arteries carry $O_{2}$ rich blood from the heart to all parts of the body while veins carry CO2 rich blood from different parts of the body to heart.

                                                              

    Q.5. Define dialysis. Also, write a short note on kidney failure.

    Answer: The process of purifying blood through an artificial kidney is called dialysis. Kidneys are major organs of excretory system. Their efficiency gradually decline with age. Its efficiency may also decline due to some other causes. This decline in the performance of kidney is called kidney failure.

    Q.6. What do you mean by transpiration? How does it help the plants?
    Answer: Most of the water absorbed by roots evaporates through the stomata. This Loss of water in the form of water vapours from the stomata is called transpiration.

    VII. Long Answer Questions.

    Q.1. Describe the components of human circulatory system with the help of a well labelled diagram. Explain them briefly.

    Answer: Components of human circulatory system are heart, blood vessels and blood. Heart- The human heart consists of four chambers. The upper two chambers are called atria (singular atrium] and the Lower two chambers are called ventricles. The left part of the heart is separated from the right part of the heart with the help of a septum.

          

    Blood is a fluid which flows in vessels and helps to transport digested food, gases and waste products.
    Blood consists of following four types of components:

    (i) Red blood cells. These cells contain red pigments, called haemoglobin. Due to the presence of haemoglobin blood appears red. Haemoglobin plays a very important role in transport of oxygen from Lungs to cells and carbon dioxide from cells to Lungs.

    (ii) White blood cells – These cells fight against the germs that enter in our body and protect us from the diseases.

    (iii) Platelets- These are also a type of cells that help in clotting at the time of injury. (iv) Plasma – It is the fluid component of blood in which all types of blood cells remain scattered.

    Q.2. How does the process of excretion occur in animals? Describe human excretory system properly.
    Answer: Human excretory system consists of two kidneys, two ureters, one urinary bladder, and a urethra.

    Kidney is the main organ of excretory system. It filters the blood and removes waste products to form urine. This urine get stored in the urinary bladder through ureters. Here, urine is stored until the presence of expanded bladder leads to urge to pass it out through the urethra.
    About 1 to 1.8 l urine is discharged by an adult human within 24 hours. Urine contains 95% water, 2.5% urea and 2.5% other waste products.

    Sweating is another way of excretion in which body removes water and salt in the form of sweat.

    Q.3. (a) Demonstrate the movement of water and minerals between the cells of a plant with the help of a diagram.
    (b) Give an activity to compare the number of stomata on both sides of a leaf.

    Answer: (a) On the root, many thread like structures are present. These structures are called root hair. They help to increase the absorption of water and minerals from the soil by increasing the surface area. This absorbed water along with the minerals is transported upward with the help of xylem tissue. Water has a tendency to move from a cell having low solute concentration to high solute concentration. Due to this characteristic water reaches to the xylem of root from the soil and then other parts of plants   .


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