1. Question : Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
Column I Column II
(i) Stomata (b) Transpiration
(ii) Xylem (d) Transport of water
(iii) Root hairs (a) Absorption of water
(iv) Phloem (c) Transport of food
2. Question : Fill in the blanks.
(i) The blood from the heart is transported to all parts of the body by the arteries.
(ii) Haemoglobin is present in red blood cells (RBC) cells.
(iii) Arteries and veins are joined by a network of capillaries
(iv) The rhythmic expansion and contraction of the heart is called heartbeat.
.(v) The main excretory product in human beings is urea
(vi) Sweat contains water and salts.
(vii) Kidneys eliminate the waste materials in the liquid form called urine
.(viii) Water reaches great heights in the trees because of suction pull caused by evaporation of water from leaves due to process of transpiration
3.Question : Choose the correct options:
(a) In plants, water is transported through
(i) Xylem (ii) Phloem (iii) Stomata (iv) Root hair
Answer : (a) In plants, water is transported through -- (i) Xylem
(b) Water absorption through roots can be increased by keeping the plants
(i) in the shade (ii) in dim light (iii) under the fan (iv) covered with a polythene bag
Answer : (b) Water absorption through roots can be increased by keeping the plants -- (iii) under the fan
4. Question :Why is transport of materials necessary in a plant or in an animal?
Answer : Transport of materials is necessary in plant or in animals as all organisms need food, nutrition, water and oxygen for survival. The food is the source of energy and every cell of an organism gets energy by the breakdown of glucose. The cells use this energy to carry out vital activities of life. Therefore food must be made available to every cell of an organism. They need to transport all these to various parts of their body. Further, animals need to transport wastes to parts from where they can be removed.
5. Question: What will happen if there are no platelets in the blood?
Answer : The platelets are another type of cells in blood, which are responsible for formation of clot in blood when it comes in contact with air. So this prevents excess bleeding from the injury as it plugs the skin opening by clout formation on it. If there are no platelets in the blood,.then we may die from a small injury due to excess blooding as there will be no clotting to plug it.
6. Question :What are stomata? Give two functions of stomata.
Answer : Stomata are tiny pores present on the surface of the leaves. These pores are surrounded by ‘guard cells’
The two functions of Stomata
Function 1 : We know that photosynthesis is an important process in Plants, in which plants, in the presence of sun light with help of chlorophyll, make use of simple chemical substances like carbon dioxide, water and minerals for the production of food for them selves. The carbon dioxide required in this process is made available by Stomata, through direct absorption from the air .
Function 2 : Stomata helps in 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.
7. Question: Does transpiration serve any useful function in the plants? Explain.
Question : 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.
8. Question :What are the components of blood?
Answer : The main components of bloods are :
1. Plasma: The fluid part of the blood is called plasma.
2. Red Blood Cells (RBC) contain a red pigment called haemoglobin. Haemoglobin bind 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.
3. White Blood cells (WBC) fight against germs that may enter our body thus provide an effective defense against infection, disease etc.
4. Platelets : They are another type of cells in blood, responsible for the formation of dark red clot in the blood when it comes in contact with air. They helps in preventing excess bleeding from the injuries by plugging the skin openings or cuts with a thick dark red clot.
9. Question : Why is blood needed by all the parts of a body?
Answer : The blood is needed by all parts of the body as 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.
10. Question :What makes the blood look red?
Answer : The presence of haemoglobin makes blood appear red. Haemoglobin bind 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.
11. Question: Describe the function of the heart.
Answer : The heart is an organ which beats continuously to act as a pump for the transport of blood, which carries other substances with it. The heart is located in the chest cavity with its lower tip slightly tilted towards the Left . heart is roughly the size of a fist. To avoid mixing up of blood rich in oxygen with the blood rich in carbon dioxide, 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.
To understand the functioning of the circulatory system, start from the right side of the heart as show in the in Fig and follow the arrows. These arrows show the direction of the blood flow from the heart to the lungs and back to the heart from where it is pumped to the rest of the body.
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. The rhythmic beating of the various chambers of the heart maintain circulation of blood and transport of substances to the different parts of the body.
12. Question: Why is it necessary to excrete waste products?
Answer : 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.
13. Question: Draw a diagram of the human excretory system and label the various parts.
Extended Learning — Activities and Projects
1. Find out about blood groups and their importance.
2. When a person suffers from chest pain, the doctor immediately takes an ECG. Visit a doctor and get information about ECG. You may even look up an encyclopaedia or the internet.
You can read more on the following website:
Did you know?
There is no substitute for blood. If people lose blood from surgery or injury or if their bodies cannot produce enough blood, there is only one way to get it — through transfusion of blood donated by volunteers. Blood is usually in short supply. Donating blood does not decrease the strength of the donors.
Chapter 11.Transportation in Animals and Plants : Class VII Science CBSE NCERT Exercises Solution