Living Science 2020 2021 Solutions for Class 7 Science Chapter 12 Transportation Of Materials In Plants And Animals are provided here with simple step-by-step explanations. These solutions for Transportation Of Materials In Plants And Animals are extremely popular among Class 7 students for Science Transportation Of Materials In Plants And Animals Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Living Science 2020 2021 Book of Class 7 Science Chapter 12 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Living Science 2020 2021 Solutions. All Living Science 2020 2021 Solutions for class Class 7 Science are prepared by experts and are 100% accurate.
Page No 133:
Question 1:
In plants, the same set of pipe-like vessels transport water, mineral salts and food. Do you agree? Give reasons.
Answer:
No, the transportation of mineral salts, water and food is not done by same of vessels. The mineral salts and water are specifically transported by xylem vessels, which originate from the roots and extend to the tips of the leaves. Food, on the other hand, is transported by phloem vessels which extend from leaves to different parts of the plant.
Page No 133:
Question 2:
In osmosis, water molecules pass through a semi-permeable membrane. What is a semi-permeable membrane? What determines the direction of passage of water through such a membrane?
Answer:
A semi-permeable membrane can be described as a membrane that allows the passage of only certain types of molecules through diffusion. The direction of passage of water through a semi-permeable membrane depends on the concentration of water molecules across the semi-permeable membrane.
Page No 133:
Question 3:
Transpiration allows plants to lose excess water. It also has two other functions. What are these?
Answer:
In addition to allowing plants to lose excess water, transpiration performs following functions:
1. The water lost through transpiration creates a suction force, which helps in the absorption of mineral salts and water through the roots of the plants.
2. Transpiration also produces a cooling effect which helps in regulating the temperature of the plant.
Page No 133:
Question 4:
Under what condition will the leaves of a plant wilt?
Answer:
In case the rate of transpiration is higher than the rate of water absorbed through the roots, the leaves of a plant will wilt.
Page No 137:
Question 1:
Does Amoeba have blood?
Answer:
No, Amoeba does not have blood. The nutrients are transported in Amoeba by the process of simple diffusion.
Page No 137:
Question 2:
There are several kinds of cells in the human blood. Which one is responsible for transport of oxygen?
Answer:
The transportation of oxygen in the human blood is carried out by Red Blood Cells (RBCs). These cells possess haemoglobin which allows them to transport oxygen.
Page No 137:
Question 3:
White blood cells are said to be 'soldiers of the body'. Why are they given this name?
Answer:
The basic purpose of White Blood cells (WBCs) is to neutralise infection causing agents. These cells effectively eliminate disease causing organisms and help in the maintenance of a healthy state. This is why these cells are also referred to as 'soldiers of the body'.
Page No 137:
Question 4:
The right ventricle pumps blood to the lungs. What happens to this blood in the lungs?
Answer:
The blood that is pumped to the lungs by the right ventricle of the heart becomes oxygenated in the lungs. This oxygenated blood is then pumped to the left auricle through pulmonary vein.
Page No 137:
Question 5:
If you listen to the heart through a stethoscope, you can make out two sounds–one weak and the other strong. What are these two sounds due to?
Answer:
The weak sound namely lub that is heard through the stethoscope represents the contraction of the auricles. The strong sound called dub, on the other hand, occurs due to the contraction of the ventricles.
Page No 138:
Question 1:
Removal of all kind of waste from the body is included under 'excretion'. Do you agree? Give reasons?
Answer:
No, the removal of all kind of wastes are not included under excretion. Excretion specifically refers to the removal of metabolic wastes which generally include gaseous and liquid wastes. Solid wastes, on the other hand, are removed through the process of egestion.
Page No 138:
Question 2:
The kidneys filter wastes from the blood. Which structure in the kidneys act as filtering units?
Answer:
In the kidneys, nephrons serve as the filtration units that remove metabolic wastes from the blood.
Page No 138:
Question 3:
All animals have special excretory organs. Do you agree? Give reasons.
Answer:
No, all animals do not have special excretory organs. Lower animals including Hydra, Paramecium, and sponges do not possess any special excretory organs. These animals excrete by the process of simple diffusion. Only large animals have specialised organs that assist in excretion.
Page No 138:
Question 4:
Tests show that the urine of a patient contains sugar. What disease is the patient suffering from?
Answer:
A patient having sugar in the urine will be suffering from diabetes. In diabetic patients, blood sugar levels become very high and some of this sugar is excreted through urine.
Page No 140:
Question 1:
During transpiration water is lost from the plant in the form of
(a) water vapour
(b) liquid
(c) hydrogen and oxygen gas
(d) steam
Answer:
(a) water vapour
During transpiration, water is lost from the plant in the form of water vapour through stomata.
Page No 140:
Question 2:
The process of transportation of glucose in a plant is called
(a) transpiration
(b) respiration
(c) osmosis
(d) translocation
Answer:
(d) translocation
The process of transportation of food in the form of glucose in a plant is called translocation.
Page No 140:
Question 3:
The thinnest blood vessels in the human body are
(a) arteries
(b) veins
(c) capillaries
(d) any of these
Answer:
(c) capillaries
Capillaries are the thinnest blood vessels in the human body.
Page No 140:
Question 4:
Which of these is responsible for blood clotting?
(a) red blood cells
(b) white blood cells
(c) haemoglobin
(d) platelets
Answer:
(d) platelets
Platelets are the blood cells which prevent blood loss by blood clotting.
Page No 141:
Question 5:
When you feel you pulse, what you actually feel is blood rushing through the
(a) arteries
(b) veins
(c) capillaries
(d) platelets
Answer:
(a) arteries
We feel the blood rushing through the arteries while feeling our pulse.
Page No 141:
Question 6:
Blood cells that protect the body from diseases are
(a) RBCs
(b) WBCs
(c) blood platelets
(d) all of these
Answer:
(b) WBCs
WBCs protect our body from diseases by fighting against the bacteria and other foreign materials.
Page No 141:
Question 7:
The devices used to hear the heartbeat is called a
(a) thermometer
(b) stethoscope
(c) sphygmomanometer
(d) microscope
Answer:
(b) stethoscope
Stethoscope is the device that is used to hear the heartbeat.
Page No 141:
Question 8:
The loss of water through the stomata of leaves is called
(a) wilting
(b) translocation
(c) transpiration
(d) transportation
Answer:
(c) transpiration
The loss of water through the stomata of leaves in the form of water vapour is known as transpiration.
Page No 141:
Question 9:
In the human urinary system, which of these, in your opinion, is the most important organ?
(a) kidneys
(b) ureters
(c) urinary bladder
(d) urethra
Answer:
(a) kidneys
Kidneys are the most important organs of the human urinary system because they filter wastes from the blood.
Page No 141:
Question 10:
Which of the following are the tiny filtering units of the kidney?
(a) ureter
(b) urethra
(c) nephrons
(d) bladder
Answer:
(c) nephrons
The tiny filtering units of the kidney are known as nephrons.
Page No 141:
Question 1:
Transportation of nutrients in unicellur organisms occurs by__________
Answer:
Transportation of nutrients in unicellular organisms occurs by diffusion.
Page No 141:
Question 2:
Through which process is water and dissolved mineral salts transported from the root to other parts of the plant?
Answer:
Ascent of sap is the process by which water and dissolved mineral salts are transported from the root to other parts of the plant.
Page No 141:
Question 3:
_________ tissue is involved in transportation of food in plants.
Answer:
Phloem tissue is involved in transportation of food in plants.
Page No 141:
Question 4:
Which tissue is responsible for the transportation of materials in the human body?
Answer:
Blood is a tissue that is responsible for the transportation of materials in the human body.
Page No 141:
Question 5:
In the heart, which chambers have thicker walls-the auricles or the ventricles?
Answer:
Ventricles have thicker walls than the auricles.
Page No 141:
Question 6:
Digested food, oxygen and carbon dioxide can pass through the walls of the capillaries. True of false?
Answer:
True.
Digested food, oxygen and carbon dioxide can pass through the walls of the capillaries because they have very thin walls.
Page No 141:
Question 7:
Which protein present in red blood cells is responsible for the transportation of oxygen?
Answer:
Haemoglobin present in red blood cells is responsible for the transportation of oxygen.
Page No 141:
Question 8:
The colour of the red blood cells is due to the pigment ________
Answer:
The colour of the red blood cells is due to the pigment haemoglobin.
Page No 141:
Question 9:
You do not fall ill ever time harmful bacteria enter your body because certain cells in the body can kills the bacteria. Name the cells.
Answer:
The cells which kill the harmful bacteria every time they enter our body are called WBCs (white blood cells).
Page No 141:
Question 10:
The upper two chambers of the heart are _________ and the lower ones are ___________
Answer:
The upper two chambers of the heart are auricles and the lower ones are ventricles.
Page No 141:
Question 11:
Name the blood vessels which carry blood towards the heart.
Answer:
Veins are the blood vessels which carry blood towards the heart.
Page No 141:
Question 12:
The stretching and relaxing of arteries with each heartbeat is felt as throbbing.
What is it called?
Answer:
The stretching and relaxing of arteries with each heartbeat, which is felt as throbbing, is called pulse.
Page No 141:
Question 13:
Oxygen blood is found on the _______ side of the heart. (left/right)
Answer:
Oxygenated blood is found on the left side of the heart.
Page No 141:
Question 14:
The solid part of blood is called plasma. True of false?
Answer:
False.
Plasma is the liquid part of blood.
Page No 141:
Question 15:
Haemoglobin combines with oxygen to form carboxyhaemoglobin. True of false?
Answer:
False.
Haemoglobin combines with oxygen to form oxyhaemoglobin. Whereas carboxyhaemoglobin is formed by the combination of haemoglobin with carbon monoxide.
Page No 141:
Question 16:
Veins connect arteries with capillaries. True or false?
Answer:
False.
Capillaries connect arteries with veins.
Page No 141:
Question 17:
The only function of sweat is excretion of waste products from the body. True of false?
Answer:
False.
Sweat not only excretes waste products from the body but also helps to cool our body when it is too hot.
Page No 141:
Question 18:
Name the tiny filtering tubes present in the kidneys.
Answer:
The tiny filtering tubes present in the kidneys are called nephrons.
Page No 141:
Question 19:
In lower animals, excretion occurs by __________ from the body surface.
Answer:
In lower animals, excretion occurs by diffusion from the body surface.
Page No 141:
Question 20:
If someone's kidneys are damaged, doctors remove wastes from the body by _______
Answer:
If someone's kidneys are damaged, doctors remove wastes from their body by dialysis.
Page No 142:
Question 1:
In what ways are xylem and phloem important for transportation of materials in plants?
Answer:
Xylem and phloem are important for transportation of materials in plants because xylem transports water and minerals from the roots towards the stems, leaves and flowers, whereas phloem transports prepared food from the leaves towards the other parts of the plant.
Page No 142:
Question 2:
What is transpiration?
Answer:
The process of losing water in the form of water vapour from stomata of the leaves is known as transpiration.
Page No 142:
Question 3:
What is translocation?
Answer:
The process of transporting prepared food from the leaves to other parts of the plant through phloem cells is known as translocation.
Page No 142:
Question 4:
Name the system responsible for transportation of materials in humans. Which organs constitute this system?
Answer:
Circulatory system is responsible for transportation of materials in humans. The organs which constitute this system are blood, blood vessels and heart.
Page No 142:
Question 5:
What prevents the blood from going in the wrong direction in the heart?
Answer:
The valves present in the heart prevents the blood from going in the wrong direction in the heart.
Page No 142:
Question 6:
What is the relationship between the rate of heartbeat and pulse rate?
Answer:
When the ventricles of the heart contract, it takes blood towards the arteries under high pressure. Due to this, the arterial walls stretch. As the ventricles relax, the pressure slows down. This stretching and relaxing of the arteries with each heartbeat is known as pulse.
Page No 142:
Question 7:
Why does the rate of heartbeat increase after running?
Answer:
Page No 142:
Question 8:
What is excretion? Why is it important?
Answer:
Page No 142:
Question 9:
How is urine examination useful to the doctor?
Answer:
Page No 142:
Question 10:
What is dialysis?
Answer:
Dialysis is a process for removing waste and excess water from blood of people with damaged kidneys.
Page No 142:
Question 1:
Discuss the process of absorption of water by root hairs.
Answer:
Root hairs are in close contact with the water present in the soil. Water molecules are more dense outside the root hairs than inside of it. Hence, the water molecules are absorbed by the root hairs by the process of osmosis; that is, they move from the area having more water molecules to the area with less water molecules through a semipermeable membrane.
Page No 142:
Question 2:
What role does transpiration play in the transportation of water in a plant?
Answer:
Due to transpiration of water from the leaves, a suction pull is created, which pulls the water upwards from the roots. Due to this pull, water is forced to move upwards in trees through xylem tissue.
As water is released out during transpiration, more water is absorbed by the roots and thus rate of transportation of water increases.
Page No 142:
Question 3:
Discuss the importance of transportation of various materials in the human body.
Answer:
Importance of transportation of various materials in the human body are as follows:-
1) Food is transported to all cells of the body for growth and development.
2) Oxygen is transported to all cells of the body for respiration and various metabolic functions.
3) Waste materials are transported from body cells to the organs of excretion.
Page No 142:
Question 4:
What does the circulatory system consist of? Give the main function of each.
Answer:
The circulatory system consists of the following:
(a) Blood: Its main function is the transportation of digested food, oxygen and liquid waste from one organ of the body to other.
(b) Blood vessel: These are three in number—arteries, veins and capillaries. These exchange blood between heart and other organs of the body.
(c) Heart: Its main function is to pump blood to all parts of the body.
Page No 142:
Question 5:
Differentiate between arteries and veins. What is the importance of capillaries in the circulatory system?
Answer:
| Arteries | Veins |
| Arteries are the thick blood vessels. | Veins are the thin blood vessels. |
| They transport blood away from the heart. | They transport blood towards the heart. |
Capillaries are the thin branching of arteries through which oxygen, digested food, carbon dioxide and wastes are exchanged between blood and other surrounding cells.
Page No 142:
Question 6:
If you observe a drop of blood under a microscope, which cells would you see? What are the functions of these cells?
Answer:
If we observe a drop of blood under a microscope, we will see the following three types of cells:
1) RBC: It contains a protein haemoglobin which absorbs oxygen and transports it to all cells of the body.
2) WBC: It kills harmful bacteria and other foreign particles and protects our body from diseases.
3) Platelet: It helps in clotting of blood whenever there is wound in the body and prevents blood loss.
Page No 142:
Question 7:
With the help of a labelled diagram, trace and explain the path of blood circulation in the human body.
Answer:
Blood circulation in human body:
Human heart is divided into four chambers: the upper two are called auricles and the lower two are called ventricles. The right auricle receives deoxygenated blood from various body parts, from where it reaches the right ventricle. The right ventricle pumps blood to the lungs, where oxygen is mixed in it. From the lungs, the blood enters the left auricle and then to the left ventricle, from where it is pumped to different parts of the body.
Page No 142:
Question 8:
Draw a labelled diagram of the urinary system showing and explaining its various organs.
Answer:
Urinary system:
Urinary system consists of following parts:
(a) Kidneys: They are involved in filtering wastes from the blood.
(b) Ureters: They carry the urine from kidneys to the urinary bladder.
(c) Urinary bladder: It stores the urine until it's excreted from the body.
(d) Urethra: It is involved in the removal of urine from the urinary bladder.
Page No 142:
Question 9:
What processes take place during the period when the blood enters the kidneys till the urine leaves the body?
Answer:
Page No 142:
Question 1:
Why is the colour of blood red, through it has constituents of different colours?
Answer:
Red blood cells present in the blood consist of a red protein known as haemoglobin. Red blood cells are the most abundant in the blood. Hence, the colour of the blood is red, though it has constituents of different colours.
Page No 142:
Question 2:
Which side of the heart has oxygen-rich blood and which side has carbon dioxide-rich blood?
Answer:
Left side of the heart has oxygen-rich blood and right side of the heart has carbon dioxide-rich blood.
Page No 142:
Question 3:
If vegetables such as brinjals or ladyfingers boceme somewhat dry and srivelled, they are put in water. They start looking fresh again, because water enters inside them. In the absence of any opening, how does water enter the vegetables?
Answer:
The outer membrane of brinjals or ladyfingers are semipermeable membrane. When they are put in water, the outer area have more water molecules than the inner area. Hence, water molecules enter through the process of osmosis and they start to look fresh.
Page No 142:
Question 4:
Plants do not use all the water they absorb from the soil. Much of it is given off by transpiration. Why then do the plants absorb so much water?
Answer:
Due to transpiration of water from leaves, a suction pressure is created, which pulls water upwards from the roots. As water is released out through transpiration, more and more water is absorbed from the roots. This is the reason for absorbing so much water by the plants.
Page No 142:
Question 5:
Xylem transports sap upwards only whereas pholem transports food in both directions, Why do you think there is a difference?
Answer:
Xylem transports water and minerals from the roots to other parts of the plant. It transports sap upwards only, as all other parts of the plant are in upward direction. Phloem transports food prepared by the leaves in both upward and downward directions, as each part of the plant, whether upward or downward, needs food.
Page No 142:
Question 6:
Is removal of undigested food from the body considered to be excretion? Why?
Answer:
No. Removal of undigested food from the body is not considered to be excretion, because excretion means removal of metabolic wastes such as urea, uric acid, carbon dioxide, salts and water from the body. Whereas removal of undigested food produced in the body is called egestion.
Page No 143:
Question 7:
The ventricles have thick muscular walls whereas the auricles have thin walls. Why do you think thick muscular walls are necessary in the ventricles and not in the auricles?
Answer:
The ventricles have thicker muscular walls than the auricles. Blood flows in the ventricles under high pressure, as they have to pump blood to all body parts. The auricles have thin muscular walls. Blood flows into them under lower pressure, as they have to pump blood only to the ventricles.
Page No 143:
Question 1:
A researcher in Chennai wants to study how much carbohydrate is burnt up in the body in a long distance race. She measured the body weight of athletes before and after a 2 km race. She found to her surprise that each athlete lost 1 kg or more. The athletes could not have burnt 1 kg carbohydrates in their bodies in a 2 km race, she thought.
Answer these questions.
1. What do you think the reduction in body weight was due to?
2. Do you think she had designed the experiment properly?
Answer:
1. The reduction in body weight was due to loss in water of the body. As, the athletes ran for 2 kms, they must have sweated and must have lost water in the form of sweat.
Thus, their body weight was reduced by 1 kg.
2. No, she had not designed the experiment properly.
Page No 143:
Question 1:
The blood needed for transfusion in case of severe injury is mainly obtained from voluntary blood donors. In India people in the age group 18-60 are allowed to donate blood, provided a few other health requirements are met. A person who donates blood helps save lives. Would you like to regularly donate blood after you turn 18?
Answer:
Yes, I would like to donate blood once I turn 18. Donating blood is a very noble cause. Blood from a single donor can save many lifes.
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