Class 7 Science Chapter 11 Important Questions
Class 7 Science Chapter 11 Important Questions Answers and Main Keywords of Transportation in Animals and Plants free to use or download. All the extra questions taken from all the topics given in latest NCERT Books for session 2020-2021.These important extra questions are helpful for clearing the concepts and preparation of the exams. After reading NCERT Textbook once, go through these questions to be confident in the class.
Class 7 Science Chapter 11 Important Questions for 2020-2021
|Chapter: 11||Transportation in Animals and Plants|
|Contents:||Important Questions with Answers|
Class 7 Science Chapter 11 Important Questions Set – 1
What is transport? Why do organisms need these types of systems in their body?
In biology, transport is a life process in which a material absorbed or made in one part of the body of an organism is carried to other parts in its body. All organisms need food, water and oxygen for survival. These materials must reach the various parts of an organisms where they are needed. Further, animals need to transport wastes to parts from where they can be removed as they are harmful for the body.
What is blood?
Blood is a red colored liquid which flows in blood vessels and circulates in our body. Blood is red because it contains a red pigment called “hemoglobin”. Blood consists of four components; plasma, red blood cells, white blood cells and platelets. All components have different work.
In most of the animals, the blood that circulates in their body transport or carries food, water and oxygen to cell in all the parts of the body. The main transport system in human beings is the blood which is commonly known as circulatory system.
Write short note on components of blood.
Blood is a liquid, which has cells of various kinds suspended in it. The fluid part of the blood is called “plasma”. 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. 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”.
Write down the function of blood in circulatory systems.
Blood is the fluid which flows in blood vessels. Blood is needed by all the parts of our body because it performs the following important functions in our body:
- i) It transports substances like digested food from the small intestine to the other parts of the body.
- ii) It carries oxygen from the lungs to the cells of the body.
- iii) It also transports waste for removal from the body.
- iv) It carries oxygen from the lungs to different organs.
- v) And blood also fights against infections and diseases.
What do you mean by “pulse and pulse rate”?
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. This throbbing is called the pulse and it is due to the blood flowing in the arteries. Place the middle and index finger of your right hand on the inner side of your left wrist. The number of beats per minute is called the pulse rate. A resting person, usually has a pulse rate between 72 and 80 beats per minute.
Class 7 Science Chapter 11 Important Questions Set – 2
Write short note on arteries and veins.
There are different types of blood vessels in the body. 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.
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.
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.
“An artery always carries oxygen-rich blood” – Comment.
The pulmonary artery carries blood from the heart, so it is called an artery and not a vein. It carries carbon dioxide-rich blood to the lungs. Pulmonary vein carries oxygen-rich blood from the lungs to the heart.
What do you know about “Capillaries”?
Capillaries are the extremely thin blood vessels which connect arteries to veins. Every cell of the body is near a capillary. The capillaries have extremely thin walls which allow substances to pass from blood into the body cells and also from the body cells into the blood. The oxygenated blood from arteries enters into the capillaries in all the parts of the body. The various dissolved substances present in the blood (like food and oxygen) pass into body cells through the thin walls of the capillaries.
Discuss the functions of blood capillaries in human body.
Capillaries are present throughout our body. The arteries divide into smaller vessels. On reaching the tissues, they divide further into extremely thin tubes called capillaries. The capillaries join up to form veins which empty into the heart. The various dissolved substances present in the blood (like food and oxygen) pass into body cells through the thin walls of the capillaries.
At the same time the waste products (like carbon dioxide) form in the body cells enter into plants through the thin walls of capillaries. The exchange of substances i.e., like food, oxygen, carbon dioxide etc., between the blood and the body cells take place through capillaries. The other end of capillaries are joined to veins. The deoxygenated blood containing waste product like carbon dioxide, coming from the capillaries enter into veins and carried back to the heart.
What do you know about human heart?
The heart is an organ which pumps blood to the all parts of our body through a network of tubes called blood vessels. Our heart “beats” continuously to circulate blood in the body. The heart works like a pump non-stop throughout our life. Our heart is located in the chest cavity slightly towards the left side. The heart lies between the two lungs and above the diaphragm. The size of our heart is roughly equal to our fist. The heart is made of special muscle called “cardiac muscle” but it is not solid muscle. The heart is hollow inside. The heart has four compartments called “chambers”. The upper two chambers of heart are called “atrium” and the lower two chambers of heart is called “ventricles”. On the left side of the heart are left atrium and left ventricle and the right side of the heart are right atrium and right ventricle.
Class 7 Science Chapter 11 Important Questions Set – 3
Are you familiar with the word “heartbeat”? Write something about it.
Yes, when we place our hand on the left side of our chest, we can feel our heartbeat. 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. Remember that heartbeats continue every moment of our life.
What is “stethoscope”?
The doctor feels our heartbeats with the help of an instrument called a stethoscope. 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. Doctors can get clues about the condition of our heart by listening through a stethoscope.
Write down something about discovery of blood circulation.
The English physician, William Harvey (A.D.1578 to 1657), 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 “icirculatori”. He lost most of his patients. However, before he died, Harvey’s idea about circulation was generally accepted as a biological fact.
What do you know about the circulatory system of hydra and sponge?
Animals such as sponges and hydra do not possess any circulatory system. The water in which they live brings food and oxygen as it enters their bodies. The water carries away waste materials and carbon dioxide as it moves out. Thus, these animals do not need a circulatory fluid like the blood.
What do you mean by “excretion and excretory system”?
We know that carbon dioxide is removed as waste from the body through the lungs during exhalation and the undigested food is removed during egestion. 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.
Class 7 Science Chapter 11 Important Questions Set – 4
Discuss the excretory system in humans.
The waste which is present in the blood has to be removed from the body. Our body have a mechanism to filter the blood. This is done by the blood capillaries in the kidneys. 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. The kidneys, ureters, bladder and urethra form the excretory system. An adult human being normally passes about 1 to 1.8 lit., of urine in 24 hours. The urine consists of 95% water, 2.5% urea and 2.5% other waste products. We have sweat glands. These are found over most of the body part. Sweating helps to remove excess water, some salts and a little of urea as liquid waste from the body, and sweating helps to keep our body cool during hot summer days
What do you mean by “dialysis”?
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.
Veins have valves which allow blood to flow only in one direction. Arteries do not have valves. Yet the blood flows in one direction only. Can you explain why?
Veins have valves to prevent blood from flowing backwards. Arteries also carry blood only in one direction but they do not have valves. This is because the blood flows through them at high pressure. Their thick and elastic walls can withstand the high pressure of blood.
Anjali noticed water being pulled up by a motor pump to an overhead tank of a 5 storeyed building. She wondered how water moves up to great heights in the tall trees standing next to the building. Can you tell how?
When the water is pulled up by a motor pump to an overhead tank of a 5 storeyed building, it moves to a great height due to the suction pull created by the pump. This pull forms a continuous column of water and water rises up to a great height.
Similarly, when transpiration occurs in the leaves of a tall tree water is evaporated through the pores called stomata. The continuous evaporation creates a suction force. Due to this, suction force, water from the soil rises up through the roots of plants and reaches to a great height in tall trees.
How does the aquatic animals and land animals (lizard, snake etc.) excreted?
The way in which waste chemicals are removed from the body of the animal depends on the availability of water. Aquatic animals like fishes, excrete cell waste as ammonia which directly dissolves in water. Some land animals like birds, lizards, snakes excrete a semi-solid, white colored compound (uric acid).
Class 7 Science Chapter 11 Important Questions Set – 5
How does root of the plants absorb the water and minerals?
Plants absorb water and minerals by the roots. The roots have root hair. The root hair increases 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. Plants have pipe-like vessels to transport water and nutrients from the soil. The vessels are made of special cells, forming the vascular tissue. The vascular tissue for the transport of water and nutrients in the plant.
When does dialysis treatment become necessary to take by a person?
It becomes necessary to take such a treatment when there is complete failure of both the kidneys. In such cases, accumulation of urea in the person’s blood take place. This can ultimately kill the person if the blood is not filtered artificially.
Name the only artery that carries carbon dioxide rich blood.
The only artery that carries carbon dioxide rich blood is “pulmonary artery”. It carries deoxygenated blood from the right ventricle of the heart to the lungs.
How does transpiration occur in the plants?
Plants absorb mineral nutrients and water from the soil. Not all the water absorbed is utilized 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.
What is the special feature present in a human heart which does not allow mixing of blood when oxygen rich and carbon dioxide rich blood reach the heart?
In human, the heart has four chambers. The two upper chambers are called the “atria” and the two lower chambers are called the “ventricles”.
On the left side are the “left atrium and left ventricle” and on the right side of the heart are “right atrium and right ventricle”.
The left side of the heart is completely separated from its right side by means of a partition of thick muscles called the “septum”. The septum prevents the mixing of oxygenated blood on the left side with the deoxygenated blood on its right side.