Selina Concise Solutions for ICSE Class 9 Biology Chapter 10 Nutrition

PAGE NO: 215

Question 1:
Answer: 1. (c) Fructose and glucose
2. (d) Potassium - Banana
3. (b) and (c). (Note: Marasmus is mainly caused due to the deficiency of proteins, but as per the options provided, the right answer would be both carbohydrates and fats.)
4. (a) A, D and E
5. (c) Carrot
6. (a) C
Nutrition involves choosing the right foods to provide your body with essential vitamins and minerals. Understanding which foods contain specific nutrients helps us build a healthy diet for growth and energy.
Teacher's Tip: Use the phrase "Vitamin C for Citrus" to remember where to find it.
Exam Tip: For multiple-choice questions, always write the full text of the option alongside the letter for better clarity.

Question 2:
Answer: (a) T (True)
(b) F (False). Kwashiorkor is a severe protein deficiency disease.
(c) F (False). Iodine is required for the proper working of thyroid.
(d) F (False). Antibodies are proteins produced by the immune system of the body, when it detects harmful substances called antigens.
(e) T (True)
Deficiency diseases occur when our diet lacks specific nutrients over a long period. Proteins and minerals like iodine are vital for the body's internal systems to function correctly.
Teacher's Tip: Think of antibodies as the body's "soldiers" that fight off germ "invaders."
Exam Tip: When a statement is false, always provide the corrected fact to demonstrate your complete understanding.

Question 3:
Answer: (i) Fluorine
(ii) Iodine
(iii) Iron
Minerals are inorganic elements that the body needs in small amounts for various functions. For example, iron is essential for the blood to carry oxygen throughout our system.
Teacher's Tip: Remember "Iron for blood" and "Iodine for the neck (thyroid)."
Exam Tip: One-word answers must be spelled correctly to get full marks, especially scientific terms.

Question 4:
Answer: (i) Monosaccharides
1. Glucose: Provides an instant source of energy
2. Fructose: Needed for maintaining a healthy body
(ii) Disaccharides
1. Sucrose: Needed for good health
2. Maltose: Further broken down to produce glucose molecule which provides energy to the body
(iii) Polysaccharides
1. Cellulose: Acts as roughage which prevents constipation
2. Glycogen: Reserve carbohydrate in humans and stored in liver and muscles
Carbohydrates are the main energy source for our bodies and come in different levels of complexity. Simple sugars like glucose give fast energy, while complex ones like glycogen store it for later use.
Teacher's Tip: Think of Monosaccharides as "Single" sugars and Disaccharides as "Double" sugars.
Exam Tip: Be sure to link the specific carbohydrate to its correct use, like cellulose for digestion.

Question 5:
Answer: Balanced diet is defined as the one which contains all the principal constituents of food in proper quantity. Balanced diet is the one that provides at least 50% of energy from carbohydrate, 35% from fat, and 15% from protein. The precise optimal quantities of each nutrient will vary with age, sex and activity.
A balanced diet ensures that your body gets exactly what it needs without overdoing any one type of food. It acts as a blueprint for long-term health and prevents various nutritional deficiencies.
Teacher's Tip: Use a "Food Plate" image in your mind to visualize the different percentages of nutrients.
Exam Tip: Memorize the specific percentages (50-35-15) as they are often required for a complete definition.

Question 6:
Answer: Bones are generally made of calcium and iron. Milk and milk products are rich in calcium and Vitamin A. That is why, a doctor advises a bone patient to include more of milk and milk products in his everyday food to make his bones and teeth strong. Milk also prevents oxidation of Vitamin A. Calcium present in milk even helps in clotting of blood. Milk, is therefore a wholesome food.
Milk is often called a "complete food" because it contains almost all the nutrients required by the human body. Its high calcium content is specifically needed to keep our skeletal structure dense and healthy.
Teacher's Tip: Drink a glass of milk daily to keep your bones as strong as a "Calcium Castle."
Exam Tip: Mention the role of calcium in "clotting of blood" as it is a less common but important scientific fact.

Question 7:
Answer: Need for food by the body:
1. Growth: Food is necessary for building new protoplasm or cells. This helps in the growth of an organism.
2. Repair: Food provides materials for the repair of worn out or damaged cells and tissues.
3. Energy: We obtain energy from food. This energy is required for carrying out various life functions.
4. Maintenance: Nutrients obtained through food help to maintain the chemical composition of cells.
5. Provision of raw materials: Raw materials required for the synthesis of products such as enzymes, hormones, sweat, milk, etc. are obtained through food.
6. Protection: Food provides protection from diseases and infection.
Food is the fuel and building material for every single part of our bodies. Without it, our cells could not repair themselves or produce the chemicals needed for us to think and move.
Teacher's Tip: Think of food as the "Construction Crew" and "Fuel Station" for your body.
Exam Tip: When listing needs for food, use clear headings like Growth, Repair, and Energy for better presentation.

Question 8:
Answer: Proteins are the body building foods. They provide the chemical material for the growth and repair of body cells and tissues. At the time of emergency, proteins can also be oxidized in the body to release energy. Protein deficiency disease of young children: Kwashiorkor
Proteins are made of amino acids which act as the bricks and mortar for our muscles and skin. If a child does not get enough protein, their body cannot develop properly, leading to diseases like Kwashiorkor.
Teacher's Tip: Remember: "Proteins for Pumping Muscles" and "Proteins for Patching Tissues."
Exam Tip: Identify proteins as "body building foods" to use the standard textbook terminology.

Question 9:
Answer: Whole grain atta, fruits and green leafy vegetables are the chief sources of roughage.
1. Roughage does not provide any nutrients to our body. It still has nutritive value and is essential for the proper functioning of the gut.
2. It absorbs a lot of water and retains it. In this way, it keeps faecal matter soft preventing constipation.
3. It combines with intestinal waste and makes it bulky.
4. It helps in the formation of stools and helps our body to expel the undigested waste food.
5. Roughage expands the intestinal lumen and helps in slow and smooth movement of food through the gastrointestinal tract. This movement is required for proper and complete digestion of food and for the elimination of intestinal waste.
6. Roughage stimulates secretion from the digestive tract and also helps in removal of cholesterol, fatty secretory substances and toxins from the body.
Even though we cannot digest roughage, it is one of the most important parts of our diet for healthy digestion. It acts like a biological broom that sweeps through our intestines to keep everything moving smoothly.
Teacher's Tip: Imagine roughage as the "scrubbing sponge" that keeps your digestive tubes clean.
Exam Tip: Highlight that roughage "prevents constipation" as this is its most well-known and important function.

Question 10:
Answer: (i) Thiamine - Whole grain - Beri-beri
Niacin - Milk - (ii) Pellagra
(iii) Ascorbic acid - (iv) Citrus fruit - Scurvy
Calciferol - (v) Fish liver oil - (vi) Rickets
(vii) Retinol - Carrot, yellow fruit - (viii) Night blindness
Vitamins are organic compounds needed in tiny amounts but their absence can cause major health problems. Each vitamin has a unique source, like sunlight for Vitamin D (Calciferol) or citrus for Vitamin C (Ascorbic acid).
Teacher's Tip: Match the "A" in Retinol with "A" in Night blindness to remember the pair.
Exam Tip: Use both the common name (e.g., Vitamin C) and chemical name (e.g., Ascorbic acid) if you know both.

Question 11:
Answer: Iodine - Promotes the secretion of thyroxine by the thyroid gland - Iodised salt, sea foods
Iron - Formation of haemoglobin - Whole cereals, fish
Calcium - Allows muscle contraction and clotting of blood - Dairy foods, beans
Potassium - Controls nerve and muscle activity, fluid balance, secretion of neurotransmitter - Banana, potato
Minerals are the "structural workers" of the body, helping with everything from bone strength to nerve signals. Getting these from natural food sources ensures our body's internal chemistry remains balanced.
Teacher's Tip: Remember "Banana for Potassium" because it helps your muscles avoid cramps.
Exam Tip: Focus on the specific body part or function (like thyroid or haemoglobin) for each mineral.