CBSE – 7th Standard Science

Question Bank – Chapter 11 – Transportation in Animals and Plants


Transportation in Animals and Plants


Q.1 What is the importance of blood in our body?
Ans. Blood is the fluid which flows in blood vessels. It transports substances like digested food from the small intestine to the other parts of the body. It carries oxygen from the lungs to the cells of the body. It also transports waste for removal from the body.  Blood is a liquid, which has cells of various kinds suspended in it.



Q.2. What do you understand by the term ‘haemoglobin’?

Ans. One type of cells are the red blood cells (RBC) which contain a red pigment called haemoglobin. Haemoglobin binds with oxygen and transports it to all the parts of the body and ultimately to all the cells. It will be difficult to provide oxygen efficiently to all the cells of the body without haemoglobin. The presence of haemoglobin makes blood appear red.


Q.3. What are white platelets?

Ans. The blood also has white blood cells (WBC) which fight against germs that may enter our body. The clot is formed because of the presence of another type of cells in the blood, called platelets.


Q.4. What are blood vessels and how many types of blood vessels are there?

Ans. There are different types of blood vessels in the body. You know that during inhalation a fresh supply of oxygen fills the lungs. Oxygen has to be transported to the rest of the body. Also, the blood picks up the waste materials including carbon dioxide from the cells. This blood has to go back to the heart for transport to the lungs for removal of carbon dioxide. So, two types of blood vessels, arteries and veins are present in the body.


Q.5. Explain the difference between arteries and veins?

Ans. Arteries carry oxygen-rich blood from the heart to all parts of the body. Since the blood flow is rapid and at a high pressure, the arteries have thick elastic walls whereas Veins are the vessels which carry carbon dioxide-rich blood from all parts of the body back to the heart. The veins have thin walls. There are valves present in veins which allow blood to flow only towards the heart.


Q.6. What is the function of Heart in our body?

Ans. The heart is an organ which beats continuously to act as a pump for the transport of blood, which carries other substances with it. Our heart works like a pump non-stop. The heart is located in the chest cavity with its lower tip slightly tilted towards the left. The blood rich in oxygen and the blood rich in carbon dioxide does not mix with each other because, the heart has four chambers. The two upper chambers are called the atria (singular: atrium) and the two lower chambers are called the ventricles. The partition between the chambers helps to avoid mixing up of blood rich in oxygen with the blood rich in carbon dioxide.


Q.7. What is a heartbeat?

Ans. The walls of the chambers of the heart are made up of muscles. These muscles contract and relax rhythmically. This rhythmic contraction followed by its relaxation constitute a heartbeat. A doctor uses the stethoscope as a device to amplify the sound of the heart. It consists of a chest piece that carries a sensitive diaphragm, two ear pieces and a tube joining the parts.


Q.8. Explain the term ‘excretion.’?

Ans. When our cells perform their functions, certain waste products are released. These are toxic and hence need to be removed from the body. The process of removal of wastes produced in the cells of the living organisms is called excretion. The parts involved in excretion forms the excretory system.


Q.9. Who discovered the circulation of blood?

Ans. The English physician, William Harvey (A.D.1578ñ1657), discovered the circulation of blood. The current opinion in those days was that blood oscillates in the vessels of the body.

For his views, Harvey was ridiculed and was called ìcirculatorî. He lost most of his patients. However, before he died, Harveyís idea about circulation was generally accepted as a biological fact.


Q.10. What are the functions of bladder and ureters?

Ans. When the blood reaches the two kidneys, it contains both useful and harmful substances. The useful substances are absorbed back into the blood. The wastes dissolved in water are removed as urine. From the kidneys, the urine goes into the urinary bladder through tube-like ureters. It is stored in the bladder and is passed out through the urinary opening at the end of a muscular tube called urethra.


Q.11. Explain the process of dialysis?

Ans. Sometimes a person’s kidneys may stop working due to infection or injury. As a result of kidney failure, waste products start accumulating in the blood. Such persons cannot survive unless their blood is filtered periodically through an artificial kidney. This process is called dialysis


Q.12. Explain the process of Transportation of water and Minerals in plants?

Ans. Plants absorb water and minerals by the roots. The roots have root hair. The root hair increase the surface area of the root for the absorption of water and mineral nutrients dissolved in water. The root hair is in contact with the water present between the soil particles.


Q.13. What is a xylem?

Ans. Plants have pipe-like vessels to transport water and nutrients from the soil. The vessels are made of special cells, forming the vascular tissue. A tissue is a group of cells that perform specialised function in an organism. The vascular tissue for the transport of water and nutrients in the plant is called the xylem. The xylem forms a continuous network of channels that connects roots to the leaves through the stem and branches and thus transports water to the entire plant.


Q.14. What is transpiration?

Ans. Plants absorb mineral nutrients and water from the soil. Not all the water absorbed is utilised by the plant. The water evaporates through the stomata present on the surface of the leaves by the process of transpiration. The evaporation of water from leaves generates a suction pull (the same that you produce when you suck water through a straw) which can pull water to great heights in the tall trees. Transpiration also cools the plant.