CBSE Class 7 - Science - CH11 - Transportation in Animals and Plants

Transportation in Animals and Plants

Human Heart
(credits:wpclipart)

NCERT Solution, Q & A

Q1(NCERT): Fill in the blanks.

i.     The blood from the heart is transported to all parts of the body by the ___________________.

ii.    Haemoglobin is present in ______________ cells.

iii.   Arteries and veins are joined by a network of ______________.

iv.   The rhythmic expansion and contraction of the heart is called _________________.

v.    The main excretory product in human beings is _____________.

vi.   Sweat contains water and _______________.

vii.  Kidneys eliminate the waste materials in the liquid form called _______________.

viii. Water reaches great heights in the trees because of suction pull caused by _____________.


Answer:

i.     arteries
ii.    red blood cells (RBCs)
iii.   capillaries
iv.    heartbeat
v.     urea
vi.    salt
vii.   urine
viii.  transpiration.

Q2: What do you mean by circulatory system?

Answer: The organ system which consists of heart, blood vessels and blood together constitute the circulatory system.

Q3(NCERT): 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
	(e) Synthesis of carbohydrates

Answer:

Column I	Column II
(i) Stomata	(b) Transpiration, (e) Synthesis of carbohydrates
(ii) Xylem	(d) Transport of water
(iii) Root hairs	(a) Absorption of water
(iv) Phloem	(c) Transport of food

Q4: Name the scientist who discovered blood circulation.

Answer: William Harvey


Q5(NCERT):Choose the correct options:
(a) In plants, water is transported through

(i) Xylem
(ii) Phloem
(iii) Stomata
(iv) Root hair

Answer: (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: (iii) under the fan
Explanation: The wind speed because of fan will increase the transpiration process. More water is lost by the plants thus creating a higher suction pull.

Q6: What is wilting of plants?

Answer: If water is lost more quickly than it is absorbed by the root hairs, it will result in loss of water in plants. The leaves, flower and stem of the plant droop. It is known as wilting.


Q7(NCERT): Why is transport of materials necessary in a plant or in an animal? Explain.

Answer: Transport of materials is necessary in plants and animals due to following reasons:

1. All livings beings need food, water and oxygen for survival and to perform various activities. It is necessary to transport these materials to various parts of the body.
2. Food and oxygen are transported to all cells of the body so that they can generate energy and grow.
3. Waste products generated by cells need to be transported to excretory organs. If it does not happen, the organism may die because of poisoning by these waste material.

Q8: What is vascular system of plants?

Answer: Higher plants have well defined transport system called vascular system. It consists of pipe-like vessels called xylem and phloem.

Xylem tissues join together and form long tubes. They transport water and minerals from roots to all parts of the plant.

Phloem tissues also join together and form long tube which carry food from leaves to various parts of the plant body.

Q9(NCERT): What will happen if there are no platelets in the blood?

Answer: Platelets help in clotting of blood whenever there is a wound on the body. If platelets are not present in the blood, clotting will not happen and bleeding will continue. The prolonged blood loss may result in death of the person.
When platelets are absent and there is no blood clotting occurs, this disease is called haemophilia.

Q10: Name the various transport systems present in human beings and mammals.

Answer:

1. Circulatory System
2. Excretory System

Q11(NCERT): What are stomata? Give two functions of stomata.

Answer: Stomata are the tiny pores that present on the surface of leaves. The functions of stomata are:

1. The water evaporates through the stomata by the the process of transpiration.
2. Exchange of gases (carbon dioxide and oxygen) also take place through stomata. These gases are used in photosynthesis and respiration process in the plants.

Q12(NCERT): Does transpiration serve any useful function in the plants? Explain.

Answer:

1. Transpiration of water from leaves creates a suction pull, due to which water rises up high in tall trees. 
2. Transpiration also cools the plant.

Q13: What does blood transport in human body?

 or

Q(NCERT): Why is blood needed by all the parts of a body?

Answer: Blood is a special type of fluid that flows in blood vessels. It transports the following:

1. digested food from small intestine to other parts of the human body.
2. oxygen from lungs to heart and then to other body cells.
3. carbon dioxide from body cells to lungs via heart.
4. nitrogenous waste from body cells to kidneys for excretion from the body.

Q14(NCERT): What are the components of blood?

Answer: The main components of blood are:

1. red blood cells (RBC) - carry oxygen
2. white blood cells (WBC) - fight against germs.
3. Platelets - help in clotting of blood
4. Plasma - liquid part of blood, contains water. Carries digested food and other substances.

Q15: Which blood cells are part of our immune system?

Answer:  White blood cells (WBCs)

Q16(NCERT): What makes the blood look red?

Answer: The presence of red pigment called haemoglobin in red blood cells makes the blood look red.


Q17: Name the device used by medical practitioners to listen heart beat of the patients.

Answer: Stethoscope


Q18: What are the different types of blood vessels found in our circulatory system?

Answer: Arteries and veins.

Q19: Name the instrument used to measure blood pressure.

Answer: sphygmomanometer.

Q20(NCERT): Describe the function of the heart.

Pumping of Heart
credits:wpclipart

Answer:

1. Heart is triangular shaped organ. It is made up of cardiac muscles and is located between the lungs inside chest cavity.
2. It beats 60 to 80 times per minute throughout life. It pumps blood to all parts of the body. 
3. The heart has four chambers. The top chambers are called auricles (or atria) and the lower two chambers are called ventricles.  
4. The left chambers are completely separated from right side by a partition called septum. The chambers contain valves which allow the flow of blood in one direction only.
5. The right auricle receives carbon-dioxide rich blood from various parts of the body. The right ventricle pumps the blood to the lungs. Inside lungs, carbon-dioxide is exchanged with oxygen. (see steps 1-6 in figure below)
6. The left auricle receives oxygen-rich blood from the lungs.The left ventricle pumps this blood to the rest of the body.

(Correction:In the above diagram, ➍ is pulmonary vein carrying oxygen-rich blood)

Q21:  Why do arteries have thick elastic walls?

Answer: Arteries  carry oxygen-rich blood from the heart to all parts of the body. The blood flow is is rapid and at a high pressure, that's why arteries have thick elastic walls.

Q22:  Do arteries always carry oxygen-rich blood?

Answer: Except pulmonary artery, all arteries carry oxygen-rich blood. Pulmonary artery carries carbon dioxide rich blood from heart to lungs.

Q23: Name the only vein which carry oxygen-rich blood?

Answer: It is the pulmonary vein which carry oxygen-rich blood from lungs to heart. All other veins carry carbon dioxide rich blood.

Q24: What is a pulse?

Answer: The throbbing movement due to blood flowing in arteries is called pulse.

Q25: What do we call the study of blood?

Answer: Haematology

Q26: Name the largest artery in human body.

Answer: Aorta

Q27: Sometime doctors inject medicines directly in our bloodstream. Where do they inject in artery or in vein?

Answer: In vein. Vein are superficial and are easily locatable. Second medicine needs to be transported to all parts of the body. Through veins, medicine reaches heart and then pumped to all over the body.

Q28: What is heart beat? Name the instrument used to provide information about heart beats.

Answer: One complete contraction and relaxation of heart makes one heart beat. Electrocardiogram (ECG) is used to check rhythm of heart beats.

Q29: What is the function of blood capillaries?

Answer: The network of blood capillaries form a junction between arteries and veins. At these junctions, the exchange of gases, food materials and metabolic wastes take place.


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