ICSE Living Science Biology for Class 8 Solutions Chapter 1 Transportation of Food and Minerals in Animals and Plants
Check Your Progress
Fill in the blanks.
Question 1.
The transport system in humans consists of …………….and ……………….
Answer:
The transport system in humans consists of blood, blood vessels and heart.
Question 2
The liquid part of the blood is called ……………….
Answer:
The liquid part of the blood is called plasma.
Question 3.
Erythrocytes have a protein containing iron, called ……………..
Answer:
Erythrocytes have a protein containing iron, called haemoglobin.
Question 4
………………. are also known as blood platelets.
Answer:
Thrombocytes are also known as blood platelets.
Question 5
Circulation of blood between the heart and body organs (accept lungs) is called ………………
Answer:
Circulation of blood between the heart and body organs (accept lungs) is called systemic circulation.
Question 6
The value of the blood pressure in an adult is ……………. of mercury.
Answer:
The value of the blood pressure in an adult is 120/80 mm of mercury.
Check Your Progress 2
Write True or False.
Question 1
The lymphatic system consists of lymph vessels and lymph nodes.
Answer:
True
Question 2:
Phloem transports water and minerals upwards from the roots.
Answer:
False, Xylem transports water and minerals upwards from the roots.
Or
Phloem transports glucose made in leaves to the other parts of the plant.
Question 3
Root hair are multicellular, thin-walled outgrowths of the epidermis.
Answer: False, Root hair are unicellular, thin-walled outgrowths of the epidermis.
Question 4
The upward movement of sap that contains water and minerals is called ascent of sap.
Answer:
True.
Question 5
Water in xylem moves only in upward direction.
Answer:
True
A. Tick the most appropriate answer.
Question 1.
Which of the following blood cells are without nucleus ?
a. RBCs
b. WBCs
c. Blood platelets
d. All of these
Answer:
a. RBCs
Question 2.
Blood cells which protect the body from diseases v – are –
a. erythrocytes
b. leucocytes
c. thrombocytes
d. lymphocytes.
Answer:
b. leucocytes
Question 3.
Which of the following blood cells are responsible for clotting of blood ?
a. Erythrocytes
b. Leucocytes
c. Thrombocytes
d. Lymphocytes
Answer:
c. Thrombocytes
Question 4.
Which blood group is known as the universal recipient ?
a. A
b. B
c. AB
d. O
Answer:
c. AB
Question 5.
The finest blood vessels areb –
a. veins
b. arteries
c. aorta
d. capillaries.
Answer:
d. capillaries.
Question 6.
The vein which brings deoxygenated blood from the posterior part of the body is –
a. pulmonary vein
b. superior vena cava
c. inferior vena cava
d. none of these
Answer:
c. inferior vena cava
Question 7.
The only artery which carries deoxygenated blood is –
a. aorta
b. pulmonary artery
c. superior vena cava
d. inferior vena cava
Answer:
b. pulmonary artery
Question 8.
The artery which supplies blood to all parts of the body is –
a. pulmonary artery
b. superior vena cava
c. inferior vena cava
d. aorta
Answer:
d. aorta
Question 9.
The device used to hear the heartbeat is called a –
a. thermometer
b. stethoscope
A run deep’s L-S-Bio-8 3
c. sphygmomanometer
d. microscope
Answer:
b. stethoscope
Question 10.
The heart beats at an average of –
a. 72 times per minute
b. 120 times per minute
c. 62 times per minute
d. 90 times per minute
Answer:
a. 72 times per minute
Question 11.
Lymph contains a special type of white blood cells called –
a. monocytes
b. basophils
c. lymphocytes
d. eosinophils
Answer:
c. lymphocytes
Question 12.
The loss of water in the form of water vapour through the stomata of leaves is called –
a. wilting
b. translocation
c. transpiration
d. transportation
Answer:
c. transpiration
B. Fill in the blanks.
Question 1.
The colour of the red blood cells is due to ……………..
Answer:
The colour of the red blood cells is due to haemoglobin.
Question 2.
Blood group A has antigen ………………
Answer:
Blood group A has antigen A.
Question 3.
…………………. are the blood vessels which carry blood towards the heart.
Answer:
Veins are the blood vessels which carry blood towards the heart.
Question 4.
The upper two chambers of the heart are ……………. and the lower ones arc ………………….
Answer :
The upper two chambers of the heart are auricles and the lower ones are ventricles.
Question 5.
The pulmonary artery carries blood from ………………… to …………… the
Answer:
The pulmonary artery carries blood from heart to the lungs.
Question 6.
Oxygenated blood is found on the …………….. side of the heart.
Answer :
Oxygenated blood is found on the left side of the heart.
Question 7.
The largest artery in the body is …………….
Answer:
The largest artery in the body is aorta.
Question 8.
The stretching and relaxing of arteries with each heartbeat felt as throbbing is called ………………..
Answer:
The stretching and relaxing of arteries with each heartbeat felt as throbbing is called pulse.
Question 9.
…………….. tissue carries water in plants.
Answer:
Xylem tissue carries water in plants.
Question 10.
…………………. tissue is involved in transportation of food in plants.
Answer:
Phloem tissue is involved in transportation of food in plants. .
C. Write true or false for each statement. Rewrite the false statements correctly.
Question 1.
Haemoglobin combines with oxygen to form carboxyhaemoglobin.
Answer:
False.
Haemoglobin combines with oxygen to form oxyhaemoglobin.
Question 2.
Leucocytes are larger than erythrocytes and contain haemoglobin.
Answer:
False. Leucocytes are larger than erythrocytes and do not contain haemoglobin.
Question 3.
Blood group A has antigen A.
Answer :
True.
Question 4.
Veins connect arteries with capillaries.
Answer :
False. Capillaries connect arteries with veins.
Question 5.
Heart is enclosed by a single membrane called pericardium.
Answer:
False. Heart is enclosed by a double membrane called ‘ pericardium.
Question 6.
Walls of auricles are thinner than the walls of ventricles.
Answer:
True.
Question 7.
Between the left auricle and the left ventricle, a bicuspid valve is present which prevents the back flow of blood.
Answer:
True
Question 8.
Impure blood is received by the right auricle.
Answer:
True
Question 9.
Superior vena cava brings blood from the posterior part of the body and inferior vena cava from the anterior part of the body.
Answer:
False. Superior vena cava brings blood from the anterior part of the body and inferior vena cava from the posterior part v – of the body.
Question 10.
Pulmonary vein is the only vein which carries pure blood.
Answer:
Time
Question 11.
Phloem carries water from roots to the leaves in plants.
Answer:
False. Xylem carries water from roots to the leaves in plants.
D. Define these terms.
Question 1.
blood transfusion
2. Rh-factor
3. oxygenated blood
4. heartbeat
5. pulse
6. cardiac cycle
7. blood pressure
8. osmosis
Answer:
1. blood transfusion :
The process of transferring blood from one person to another in case of heavy loss of blood, is called blood transfusion.
2. Rh-factor – Another antigen found on the surface of red blood cells is called Rhesus factor (Rh-factor). People having Rh factor are called Rh-positive (Rh +) and the people do not having Rh- factor are called Rh-negative (Rh -)
3. oxygenated blood – Blood rich in oxygen is called oxygenated blood.
4. heartbeat – The sound (lub-dub) produced by contraction of auricles and ventricles is called heartbeat.
5. pulse- The stretching and relaxing of the arteries with each heartbeat is felt as a throbbing called pulse.
6. cardiac cycle- The sequence of events which take place during the completion of one heartbeat, is known as cardiac cycle.
7. blood pressure- The force with which the blood is pushed against the walls of the arteries is called blood pressure.
8. osmosis – The process movement of water through a semipermeable membrane from an area of high concentration to an area of low concentration is called Osmosis.
E. Write short answers.
Question 1.
What is circulatory system ?
Answer:
A specific transport system by which substances move from cell to cell in body of all living organisms is called circulatory system.
Question 2.
Write one function of circulatory system in humans.
Answer:
It helps in transportation of nutrients and respiratory gases.
Question 3.
Define oxyhaemoglobin.
Answer:
The compound formed by the combination of oxygen with haemoglobin is called Oxy-haemoglobin.
Question 4.
What are antibodies ?
Answer:
Antibodies are the chemicals released by WBCs to kill the germs and foreign particles entering our body.
Question 5.
Name the four blood groups. On what basis are they named so ?
Answer:
There are four blood group on the basis of presence or absence of substances called antigens on the surface of red blood cells.
These are :
(a) Blood group A has antigen A
(b) Blood group B has antigen B
(c) Blood group AB has antigen A and B
(d) Blood group O no antigens
Question 6.
What is pericardium ?
Answer:
A double membrane that encloses heart and protects it from shocks and jerks, is called pericardium. .
Question 7.
What prevents the blood from going in the wrong direction in the heart ?
Answer:
A muscular wall which separate left side of heart from right side and valves present between auricles and ventricles, prevents the blood from going in the wrong direction in the heart.
Question 8.
What is transpiration ?
Answer:
The loss of water in the form of water vapours through the stomata of leaves and other aerial parts of a plant is called transpiration.
Question 9.
Define wilting.
Answer:
Drooping down of leaves, stem and flowers when the I loss of water through transpiration is more quicker than it is absorbed by the root hair, is called wilting.
Question 10.
What is translocation ?
Answer:
Transportation of sugar molecules formed in the leaves during photosynthesis, through out the plant by phloem is termed as translocation.
F. Answer in detail.
Question 1.
If you observe a drop of blood under a microscope, which cells would you be observing ? What are the functions of these cells ?
Answer:
When we observe a drop of blood under a microscope, we will observe three types of cells or corpuscles, which are suspended in the liquid part called plasma.
These are :
(a) Erythrocytes or red blood cells (RBCs)
(b) Leucocytes or white blood cells (WBCs)
(c) thrombocytes or blood platelets.
(a) Erythrocytes : These are disc-shaped red blood cells, There are about 5-6 million erythrocytes in each mm3 of our blood. The mature erythrocytes do not have a nucleus. They are produced is our bone narrow. They have life span of about 120 days.
Functions : Due to presence of iron-containing protein called haemoglobin it is red in colour and carries oxygen to the different parts of the body. Oxygen combines with haemoglobin to form a compound called oxyhaemoglobin.
Haemoglobin + Oxygen → oxyhaemoglobin.
This is a reversible reaction. When blood gives oxygen to cells and tissues, oxyhaemoglobin again changes to oxygen and haemoglobin. Thereby haemoglobin becomes free to carry more oxygen.
Leucocytes – These are commonly called white blood calls (WBCs). These cells are larger than RBCs but do not contain haemoglobin, thus, they are colourless. These cells do not have any shape and nucleus. Their number is much less than RBCs, that is about 4000-13000 per mm3 of our blood.
Functions : WBCs are responsible for the defence of the organism. They help in protecting the body from infection, by ingesting foreign bodies like bacteria and virus. Because of their ability to change shape WBCs can easily reach the site of infection, surround the germs and destroy by digesting them. They also release certain antibodies which kill the germs and foreign particles entering our body.
3. Thrombocytes – These are also known as blood platelets, these are minute, disc shaped without any nucleus. These are smaller than RBCs and WBCs. They have a life span of 3-7 days. There number varies between 200000 – 400000 per mm3 our blood.
Functions : The main functions of thrombocytes is to stop the loss of blood from wounds. For this purpose they aggregate and release factors which promote the blood coagulation in case of bleeding from a wound.
Question 2.
Which blood cells can be called as the ‘soldiers’ of the body ? Give reasons. .
Answer:
Leucocytes or White Blood cells are called ‘soldiers’ of the body because they play a vital role in protecting the body from infection, by ingesting foreign bodies like bacteria and viruses. As they do not have any shape and can change their shape like an Amoeba, squeezes out ” through the blood vessels and reach the site of infection, surrounds the germs and destroy by digesting them.
They also release certain antibodies which kill the germs and foreign particles entering our body. As they help our body in fighting with disease causing germs so they are called soldiers of our body.
Question 3.
What are the functions of blood ?
Answer:
Functions of blood :
- It transports nutrients after digestion and absorption to each cell of the body.
- It transports oxygen from lungs to all the tissues and brings back carbon dioxide from the tissues to the lungs.
- Waste from all parts of the body is carried by the blood to the organs that remove this waste.
- Chemical messengers called hormones and enzymes are transported by the blood.
- It protects the body against disease-carrying germs by digesting and destroying them.
- It helps to maintain constant body temperature. This is because by constant circulation, the heat produced inour tissues gets distributed.
Question 4.
Why is a person with blood group O called a universal donor and a person with blood group AB called a universal recipient ?
Answer:
Blood from different people have different characteristics Based on these characteristics blood of human beings is classified into four groups known as A, B, AB and O. These groups are formed on the basis of presence or absence of substances called antigens on the surface of red blood cells.
There are four types of antigens.
- Blood group A has antigen A.
- Blood group B has antigen B.
- Blood group AB has both antigens A and B.
- Blood group O has neither antigen. A nor B.
Blood group O is called the universal donor since it can be given to a person with any blood group. Blood group AB is called the universal recipient since it can receive blood from a person with any blood group.
Question 5.
Explain .the process of blood circulation with the help of a schematic diagram.
Answer:
The heart pumps blood constantly throughout the lifetime of a person. The right auricle receives deoxygenated blood (blood rich in carbon dioxide) through two major veins. Deoxygenated blood is brought from the anterior part of the body through superior vena cava and from the posterior part of the body through inferior vena cava.
From the right auricle the blood moves to the right ventricle and then to the lungs through pulmonary artery. In the lungs, the blood gets oxygenated, that is, it gives off carbon dioxide and receives oxygen from the lungs. This oxygenated blood is brought to the left auricle through pulmonary vein.
From the left auricle, the blood moves to the left ventricle and from there the blood is supplied to an artery called aorta which is the largest artery in the body. The aorta further divides into arteries to supply blood to all parts of the body. As the blood passes . through capillaries, oxygen and nutrients are delivered to the cells and carbon dioxide and other wastes are collected and the blood other to the right auricle.
The circulation of blood in human heart is called double circulation as the blood circulates twice through the heart for circulating one full round throughout the body. Circulation of blood between the heart and the lungs is called pulmonary circulation. Circulation of blood between the heart and body organs (except lungs) is called systemic circulation.
Question 6.
What is the relationship between the rate of heartbeat and pulse rate ?
Answer:
Heart beat is contraction of auricles and vehtricles makes a sound called heartbeat. Pulse rate is the number of time the heart beats in one minute. Pulse rate and heart rate are the same thing. Everytime, the heart contracts it forces a pulse wave through our arteries which can be felt in any of the peripheral arteries. The pulse rate varies according to a person’s age, health and occupation.
Question 7.
Why does the rate of heartbeat increases after running ?
Answer:
As we exercise our skeletal muscles use up sugar and oxygen which are supplied to the muscles via the blood. In order to maintain adequate levels of sugar and oxygen the heart tries to speed up the rate at which the blood is circulating by pumping faster. Heart rate will increase with exercise.
As we exercise our body uses more energy because we are working harder and so during respiration we uses lots of oxygen and produces toxic CO2 Our heart has to pump harder to get more oxygen to these cells and to remove CO2 by our blood, which goes up to our lungs to get oxygerated. Hence we breathe faster to get our blood oxygenated and get rid of carbon dioxide (CO2) So, we conclude that heart rate will increase with exercise.
Question 8.
Starting from the right auricle, write the path of the blood back to the right auricle,
Answer:
The heart pumps blood constantly throughout the lifetime of a person. The right auricle receives deoxygenated blood (blood rich in carbon dioxide) through two major veins. Deoxygenated blood is brought from the anterior part of the body through superior vena cava and from the posterior part of the body through inferior vena cava.
From the right auricle the blood moves to the right ventricle and then to the lungs through pulmonary artery.
In the lungs, the blood gets oxygenated, that is, it gives off carbon dioxide and receives oxygen from the lungs. This oxygenated blood is brought to the left auricle through pulmonary vein.
From the left auricle, the blood moves to the left ventricle and from there the blood is supplied to an artery called aorta which is the largest artery in the body. The aorta further divide into arteries to supply blood to all parts of the body. As the blood, passes through capillaries, oxygen and nutrients are delivered to the cells and carbon dioxide and other wastes are collected and the blood comes back to the right auricle.
Question 9.
What is lymph ? How is it different from blood ?
Answer:
When blood reaches the capillaries, some of the water and dissolved solutes are filtered out from blood plasma into tissue spaces to form tissue fluid. Some of the tissue fluid enters tiny channels called lymph vessels and the fluid collected in them is called lymph. Basically, lymph has all the elements of blood except RBCs and blood platelets.
Difference between Lymph and Blood :
Lymph :
- It is slightly yellowish in colour. It lacks haemoglobin.
- It also lacks platelets.
- It has lymphocytes.
- It do not has erythrocytes. .
- It flows in lymph vessels and also bathes various body tissues.
- Plasma proteins are absent or very low in proteins. concentration.
Blood :
- It is red in colour due to presence of haemoglobin.
- It has platelets.
- It does not has lymphocytes.
- It has erythrocytes.
- It flows in blood vessels.
- It contains many plasma proteins
Question 10.
What is active transportation of minerals ?
Answer:
Most of the minerals needed by plants are dissolved in water in the soil. Molecules of minerals are often more crowded inside the root hair than they are in the soil. Root hairs can still absorb minerals from the soil. The movement of molecules from an area where they are present in less concentration to an area where they are present in more concentration is called active transport which requires energy Minerals are then transported through the xylem to all parts of the plant. However, active transport is not the only way by which plants take minerals from the soil. Plants can absorb minerals by diffusion also when concentration of mineral molecules is higher in the soil than inside the root.
Question 11.
How do minerals dissolved in soil water reach leaves ?
Answer:
Most of the minerals needed by plants are dissolved in water in the soil. Molecules of minerals are often more crowded inside the root hair than they are in the soil. Root hairs can still absorb minerals from the soil. The movement of molecules from an area where they are present in less concentration to an area where they are present in more concentration is called active transport which requires energy Minerals are then transported through the xylem to all parts of the plant.
However, active transport is not the only way by which plants take minerals from the soil. Plants can absorb minerals by diffusion also when concentration of mineral molecules is higher in the soil than inside the root. The water and minerals absorbed by roots are conducted upwards to the leaves, flowers and other parts of plant. The upward movement of sap that contains water and minerals is called ascent of sap.
Question 12.
How does food manufactured in leaves reach different parts of the plant.
Answer:
Sugar molecules formed in the leaves during photosynthesis are transported throughout the plant by phloem. Phloem has cells called sieve tubes which are placed one above the other to form long tubes through which food is transported. The contents of phloem can move in upward as well as downward direction whereas water in xylem moves only in upward direction.
Living Science Biology Class 8 ICSE Solutions