INTEXT QUESTIONS 22.1
1. Give two examples of autotrophs. Why do you call them so?
Answer: Examples of autotrophs: green plants and algae.
They are called autotrophs because they manufacture their own food by photosynthesis, using sunlight, carbon dioxide and water.
2. Why are autotrophs termed ‘producers’ of food chain?
Answer: Autotrophs are termed ‘producers’ in a food chain because they prepare food and become the food source for all the organisms in the food chain.
3. Fill in the blanks in the flow chart given below:
Photo
Answer: Types of nutrition:Autotrophic, Heterotrophic:—Holozoic, Parasitic, Saprophytic/ Saprotrophic.
4. The parasitic and saprotrophic modes of nutrition do not need the three processes required by holozoic animals. Which processes are these?
Answer: The three processes required by holozoic animals are ingestion, digestion and egestion.
Parasitic and saprotrophic modes of nutrition do not need these processes because they obtain already prepared food and do not need digestion of ingested food.
5. Classify the following as saprotrophs or parasites: leech, yeast, head louse, mushroom
Answer: The classification are:
Saprotrophs – Yeast, Mushroom
Parasites – Leech, Head louse
INTEXT QUESTIONS 22.2
1. In two sentences, justify the term photosynthesis (photo+ synthesis).
Answer: Photo means light and synthesis means manufacture. Plants manufacture food in presence of light.
2. What makes plants look green? What does the green pigment of plants do for them?
Answer: Plants look green because of the presence of chlorophyll.
The green pigment chlorophyll is necessary for photosynthesis, as it helps plants absorb sunlight to make their own food.
3. Glucose and starch are two food substances manufactured in the plants. Which one is formed during photosynthesis and in which form is it stored.
Answer: During photosynthesis, glucose is formed in plants. It is then converted and stored in the form of starch.
4. What role does stomata play in photosynthesis?
Answer:
INTEXT QUESTIONS 22.3
1. Why should raw vegetables and fruits be a regular item in lunch/dinner?
Answer: Raw vegetables and fruits should be a regular item in lunch/dinner because they provide roughage (dietary fibre), which helps in easy bowel movement and prevents constipation.
2. I ate one gram of starchy food and you ate one gram of fatty food—who shall get more energy you or me?
Answer: You will get more energy from one gram of fatty food.This is because 1 gram of fat provides more energy than 1 gram of starch (carbohydrate).
3. What is common between vitamins A and D and B and C to group them together?
Answer: Vitamins A and D are grouped together because they are fat-soluble vitamins.
Vitamins B and C are grouped together because they are water-soluble vitamins.
INTEXT QUESTIONS 22.4
1. Name the enzyme secreted by stomach that converts proteins into peptones.
Answer: The enzyme secreted by the stomach that converts proteins into peptones is pepsin.
2. What is the movement of muscles of oesophagus that pushes down food called?
Answer: The movement of muscles of the oesophagus that pushes food downward is called peristalsis (or peristaltic movement).
3. In which part of the alimentary canal do the pancreas and liver pour their secretions?
Answer: The pancreas and liver pour their secretions into the small intestine (duodenum).
4. Name the enzymes present in the pancreatic juice that digests proteins, carbohydrates and fats.
Answer: The enzymes present in pancreatic juice are:
(i) Trypsin → digests proteins
(ii) Amylase → digests carbohydrates
(iii) Lipase → digests fats
5. Name the acid that takes part in digestion process.
Answer: The acid that takes part in the digestion process is Hydrochloric acid (HCl). It is present in the stomach and helps in digestion.
INTEXT QUESTIONS 22.5
1. Give the full form of PEM and name the diseases due to PEM.
Answer: PEM stands for Protein Energy Malnutrition.
Diseases due to PEM are kwashiorkor and marasmus
2. If the diet continuously lacks in vitamin A, which disease may be caused?
Answer: If the diet continuously lacks Vitamin A, it may cause night blindness.
3. Why does our government frequently advertise the necessity of consuming iodised salt?
Answer: The government frequently advertises the necessity of consuming iodised salt because it contains iodine, which is necessary for the formation of thyroid hormones. It helps in the prevention of goitre and other diseases caused by iodine deficiency.
INTEXT QUESTIONS 22.6
1. Why is a system of transportation/circulation necessary for organisms?
Answer: A system of transportation/circulation is necessary for organisms to carry food, oxygen, water and other useful substances to all parts of the body and remove waste products.
2. Which kind of blood vessels are responsible for the exchange of nutrients and respiratory gases between blood and tissues?
Answer: Capillaries are the blood vessels responsible for the exchange of nutrients and respiratory gases between blood and tissues.
3. What is so special about heart that it continues beating without getting fatigued?
Answer: The heart continues beating without getting fatigued because its muscles work continuously and receive a constant supply of oxygen and nutrients through coronary blood vessels.
INTEXT QUESTIONS 22.7
1. Which blood cells would you categorise as (i) transporters of oxygen and carbon-dioxide (ii) enemies of germs that enter the body.
Answer: (i) Red Blood Cells (RBCs): Transport oxygen and carbon dioxide.
(ii) White Blood Cells (WBCs): Act as enemies of germs that enter the body and protect us from diseases.
2. Sheena has blood group O+ and Veena has AB+. Whose blood would be useful if it has to be transfused into an accident victim of unknown blood group and why?
Answer: Sheena’s blood (O+) would be more useful if it has to be transfused into an accident victim of unknown blood group because blood group O is considered a universal donor (for positive blood groups) and is less likely to cause incompatibility reactions.
3. What makes RBC s look red? What is the role of this pigment?
Answer: RBCs look red because of the presence of haemoglobin.
The role of this pigment is to carry oxygen to the tissues and bring back carbon dioxide from the tissues.
4. In which function is lymph similar to blood?
Answer: Lymph is similar to blood in that it helps prevent the body from infections and returns proteins and fluid from circulation to the tissues.
INTEXT QUESTIONS 22.8
1. Why does the trachea not deflate (collapse) during exhalation?
Answer: The trachea does not deflate (collapse) during exhalation because it is supported by rings of cartilage.
2. The sequence of parts of human respiratory are jumbled. Place them in the right order. Nasal cavity, trachea, pharynx, internal nostrils, bronchi, lungs.
Answer: The correct order of the parts of the human respiratory system is:
Nasal cavity → Internal nostrils → Pharynx → Trachea → Bronchi → Lungs
3. You have learnt in Physics that when volume increases, pressure decreases. How does this principle find a place in the process of breathing?
Answer: During inhalation, the chest cavity enlarges and the air pressure inside it decreases, so air from outside rushes in.
(i) The diaphragm straightens out.
(ii) The ribs move upward and outward.
(iii) The volume of the chest cavity increases, causing the pressure of air inside to decrease.
(iv) As a result, air rushes into the alveoli.
4. Once oxygen reaches cells, which of its organelles takes over respiration?
Answer: Once oxygen reaches the cells, the mitochondria take over respiration. They use oxygen to break down food and release energy for the cell.
5. Why are the alveoli supplied with capillaries?
Answer: The alveoli are supplied with capillaries to allow the exchange of gases (oxygen and carbon dioxide). Oxygen passes from the alveoli into the blood, and carbon dioxide passes from the blood into the alveoli to be exhaled.
INTEXT QUESTIONS 22.9
1. Name the organ of the excretory system, which stores urine before its removal from the body.
Answer: The organ of the excretory system that stores urine before its removal from the body is the urinary bladder.
2. Draw a rough diagram of the nephron and label only the part where filtration occurs?
Answer: kkkkkkkkkkkkk
3. What happens to the useful substances that move into the glomerulus along with nitrogeneous waste?
Answer: The useful substances that move into the glomerulus along with nitrogenous waste get reabsorbed into the blood capillaries surrounding the tubule.
TERMINAL EXERCISES
1. Multiple choice type questions.
i. Rickets is caused due to deficiency of:
a) Iron
b) Vitamin D
c) Proteins
d) Carbohydrates
Answer: b) Vitamin D.
[ Rickets is caused due to a deficiency of Vitamin D, which is needed for proper absorption of calcium and healthy bone development.]
ii. One gram of a substance was oxidized. The energy released amounted to 9.0Kcal. The substance was of the type:
a) Carbohydrates
b) Fats
c) Vitamins
d) Proteins
Answer: b) Fats .
[ When 1 gram of fat is oxidized, it releases about 9.0 Kcal of energy.]
iii. A person living in the hilly regions of Shimla developed swelling in his neck region. The doctor said his thyroid gland got swelled up. Name the nutrient deficient in his diet.
a) Calcium
b) Iron
c) Phosphorus
d) Iodine
Answer: (d) Iodine.
[ Swelling in the neck due to enlargement of the thyroid gland is called goitre. It is commonly caused by a deficiency of iodine in the diet. Iodine is needed for the thyroid gland to produce hormones properly.]
iv. The vitamin that helps in the clotting of blood is:
a) VitaminA
b) Vitamin D
c) Vitamin E
d) Vitamin K
Answer : (d) Vitamin K .
[ Vitamin K helps in the clotting of blood by aiding the production of clotting factors, which prevent excessive bleeding.]
v. In human beings, gas exchange between the environment and the body takes place in the :
a) larynx
b) bronchi
c) alveoli
d) trachea
Answer: (c) alveoli .
[ In human beings, gas exchange between the environment and the body takes place in the alveoli (tiny air sacs in the lungs), where oxygen enters the blood and carbon dioxide leaves the blood.]
vi. RBCs of human beings who live in high altitude regions:
a) increase in number
b) decrease in number
c) decrease in size
d) increase in size.
Answer: (a) increase in number .
[ People living at high altitudes have less oxygen available in the air, so the body produces more red blood cells (RBCs) to carry enough oxygen to body tissues.]
vii. Lungs have a large number of alveoli for:
a) maintaining a spongy texture and proper shape.
b) more surface area for diffusion of gases.
c) more nerve supply.
d) more space to increase volume of inspired air.
Answer: (b) more surface area for diffusion of gases .
[ The lungs contain a large number of alveoli because they provide a large surface area, which helps in the efficient diffusion (exchange) of oxygen and carbon dioxide.]
viii. The main function of lymph is to:
a) transport O2 to the brain.
b) transport CO2 to lungs.
c) return interstitial fluid to blood.
d) return RBCs and WBCs to lymph vessels.
Answer: c) return interstitial fluid to blood .
[ The main function of lymph is to return interstitial (tissue) fluid back to the blood circulation. It also helps in transporting fats and supporting the immune system.]
2. Name the following.
i. A fluid that transports fatty acid and glycerol.
ii. The valve present in between the chambers on the right side of the human heart.
iii. The respiratory pigment present in RBCs.
iv. The iron containing pigment in RBCs.
v. The phase of cardiac cycle in which the auricles contract.
Answer: i. Lymph
ii. Tricuspid valve
iii. Haemoglobin
iv. Haemoglobin
v. Auricular systole
3. Give on epoint of difference between the following.
1. Autotrophic and heterotrophic nutrition
2. Breathing and respiration
3. Arteries and veins
4. Blood and lymph
5. Auricular systole and ventricular systole
Answer: 1. Autotrophic nutrition and Heterotrophic nutrition
|
Autotrophic Nutrition |
Heterotrophic Nutrition |
|
Organisms prepare their own food from simple substances like CO₂ and water. |
Organisms depend on other organisms for food. |
2. Breathing and Respiration
|
Breathing |
Respiration |
|
It is the process of inhaling oxygen and exhaling carbon dioxide. |
It is the process of releasing energy from food inside cells. |
3. Arteries and Veins
|
Arteries |
Veins |
|
Carry blood away from the heart. |
Carry blood towards the heart. |
4. Blood and Lymph
|
Blood |
Lymph |
|
Red-coloured fluid containing RBCs, WBCs and platelets. |
Colourless fluid mainly containing WBCs and no RBCs. |
5. Auricular Systole and Ventricular Systole
|
Auricular Systole |
Ventricular Systole |
|
Contraction of the auricles (atria). |
Contraction of the ventricles. |
4. Match the columns A and B.
COLUMN A COLUMN B
1. Sponge-like organs located in the chest cavity a. trachea
2. Chamber acting as a common passage for food and air b. bronchioles
3. Elastic tissue that forms a flap over the top of the larynx c. epiglottis
4. Main passageway to the lungs d. pharynx
5. Small tubes that branch from the bronchi e. bronchi
6. Small air sacs in the lungs f. lungs
g. alveoli
h. larynx
Answer:
|
COLUMN A |
COLUMN B |
|
1. Sponge-like organs located in the chest cavity |
f. lungs |
|
2. Chamber acting as a common passage for food and air |
d. pharynx |
|
3. Elastic tissue that forms a flap over the top of the larynx |
c. epiglottis |
|
4. Main passageway to the lungs |
a. trachea |
|
5. Small tubes that branch from the bronchi |
b. bronchioles |
|
6. Small air sacs in the lungs |
g. alveoli |
5. Given below is an example of a certain structure and its function.
‘Kidney and excretion’
Fill in the blanks on a similar pattern.
1. Alveoli and ____________
2. Diaphragm and ____________
3. ‘C’-shaped cartilage rings and ____________
4. Erythrocyte and ____________
5. Left ventricle and ____________
6. Pacemaker and ____________
Answer: 1. Alveoli and exchange of gases
2. Diaphragm and breathing (helps in inhalation and exhalation)
3. ‘C’-shaped cartilage rings and prevent collapse of the trachea
4. Erythrocyte and transport of oxygen
5. Left ventricle and pumping oxygenated blood to the body
6. Pacemaker and regulation of heartbeat
6. What is a balanced diet? Name three items of a diet that provide three different nutrients?
Answer: A balanced diet is a diet that contains all the essential nutrients such as carbohydrates, proteins, fats, vitamins, minerals, roughage and water in the correct proportions required for proper growth and good health.
Three items of a diet providing three different nutrients:
(i) Rice – Carbohydrates
(ii) Pulses (dal) – Proteins
(iii) Butter/Oil – Fats
7. What are the main steps of photosynthesis? Is sunlight essential for photosynthesis and why?
Answer: The main steps of photosynthesis:
(i) Absorption of sunlight by chlorophyll present in the leaves.
(ii) Conversion of light energy into chemical energy and splitting of water molecules into hydrogen and oxygen.
(iii) Reduction of carbon dioxide to form carbohydrates (food).
Yes, sunlight is essential for photosynthesis because it provides the energy required for the process. Plants use this light energy to prepare food from carbon dioxide and water.
8. A patient complains of lack of appetite, exhaustion and is losing weight. Diagnose the deficiency. What kind of diet would you suggest for the patient?
Answer: The symptoms of lack of appetite, exhaustion and loss of weight indicate protein deficiency (protein-energy malnutrition).
The patient should take a protein-rich balanced diet, such as:
(a) Pulses (dal)
(b) Milk and milk products
(c) Eggs
(d) Fish and meat (if taken)
(e) Soyabean
(f) Nuts and beans
This helps in proper growth, repair of body tissues and restoring energy.
9. Deficiency of which vitamin causes night blindness. What would you suggest to prevent this deficiency?
Answer: Night blindness is caused due to the deficiency of Vitamin A.
To prevent this deficiency, include Vitamin A-rich foods in the diet, such as:
(i) Carrots
(ii) Green leafy vegetables
(iii) Milk and butter
(iv) Egg yolk
(v) Mangoes and papaya
(vi) Fish liver oil
10. Where does the digestion of starch, proteins and fats take place and what is the role played in digestion by liver and pancreas?
Answer: (a) Digestion of starch: Begins in the mouth and is completed in the small intestine.
(b) Digestion of proteins: Takes place in the stomach and is completed in the small intestine.
(c) Digestion of fats: Takes place mainly in the small intestine.
The liver secretes bile juice, which helps in breaking fats into small droplets (emulsification) and makes digestion easier.
The pancreas secretes pancreatic juice containing enzymes that help digest carbohydrates, proteins and fats in the small intestine.
11. Which component in your diet will not be digested if the enzyme lipase is not secreted?
Answer: The component that will not be digested if the enzyme lipase is not secreted is fats (or lipids).
Lipase is responsible for breaking down fats into fatty acids and glycerol. Without it, fats would remain undigested and unabsorbed in the digestive tract.
12. Explain how oxygen leaves the blood from the tissue capillaries and carbon dioxide enters the blood in the tissue capillaries.
Answer: In the tissue capillaries, oxygen is present in higher concentration in the blood than in the body cells, so it diffuses from the blood into the tissues. Carbon dioxide produced by the cells is present in higher concentration in the tissues, so it diffuses into the blood. This exchange of gases takes place through the thin walls of the capillaries.
13. Explain the usefulness of large surface area provided by alveoli for respiration in human beings.
Answer: Alveoli provide a large surface area for respiration, which helps in the rapid and efficient exchange of gases. Oxygen from the inhaled air diffuses into the blood through the alveoli, while carbon dioxide moves from the blood into the alveoli and is exhaled. This large surface area increases the efficiency of respiration in human beings.
14. Why do arteries have a thick or elastic wall?
Answer: Arteries have thick and elastic walls because they carry blood at high pressure from the heart to different parts of the body. The thick, elastic walls help them withstand this pressure and maintain smooth blood flow.
15. What are the four types of blood groups present in humans? Prepare a table with two columns to show the different human blood groups and names of compatible blood groups in the other column.
Answer: The four types of blood groups in humans are A, B, AB and O.
|
Blood Group |
Compatible Blood Groups (Can Receive Blood From) |
|
A |
A, O |
|
B |
B, O |
|
AB |
A, B, AB, O |
|
O |
O |
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