Nutrition

Nutrition is fundamentally the process by which living organisms obtain and utilize food to support all aspects of life, including growth, repair, and energy. This chapter primarily explores two main modes of nutrition: autotrophic and heterotrophic. Autotrophic nutrition is the remarkable ability of organisms, like green plants, to manufacture their own complex organic food from simple inorganic substances such as carbon dioxide and water, using sunlight as the primary energy source through the process of photosynthesis. This process, which occurs in the chloroplasts containing chlorophyll, is vital for life on Earth as it forms the base of the food chain. In contrast, heterotrophic nutrition is employed by organisms, including all animals and humans, that cannot synthesize their own food and must obtain it by consuming autotrophs or other organisms. Heterotrophs are further classified based on their feeding habits into categories like holozoic (ingesting complex food), saprophytic (feeding on dead matter), and parasitic (feeding on a host).

Focusing on human nutrition, the chapter details the digestive system and the essential components of our diet. A balanced diet for humans must include several key nutrients: carbohydrates for energy, proteins for growth and tissue repair, fats for stored energy and insulation, vitamins and minerals for regulating bodily functions and preventing deficiency diseases, roughage for proper bowel movement, and water for transportation and metabolic reactions. The human digestive system is a complex tube-like structure where this food is processed. The journey begins in the mouth with mechanical breakdown by teeth and chemical digestion of starch by salivary amylase. Food then travels to the stomach via the esophagus, where gastric juices break down proteins. The primary site of digestion and absorption is the small intestine, aided by secretions from the liver (bile for emulsifying fats) and the pancreas (enzymes for all food types). The inner lining of the small intestine has numerous finger-like projections called villi that dramatically increase the surface area for efficient absorption of digested nutrients into the bloodstream.

Finally, the chapter also covers other heterotrophic strategies observed in nature. For instance, it explains parasitic nutrition, where organisms like tapeworms live on or inside a host and derive their nourishment directly, often harming the host in the process. Another method is saprophytic nutrition, used by organisms like fungi and bacteria, which decompose dead and decaying organic material by secreting digestive enzymes onto it and then absorbing the soluble products. This process is crucial for nutrient recycling in ecosystems. Understanding these diverse nutritional patterns highlights the interdependence among living organisms and the specialized adaptations they have developed to meet their energy and growth requirements in various environments.

Multiple choice type

Question 1. 

Which one of the following pairs of nutrients includes both as simple sugars (monosaccharides)?

1. Sucrose and glucose
2. Glucose and maltose
3. Fructose and glucose
4. Maltose and lactose

Question 2. 

Which one of the following is the correct matching of a nutrient mineral element and its one rich source?

1. Calcium – Potato
2. Sodium – Citrus fruits
3. Iodine – Dairy milk
4. Potassium – Banana

Question 3. 

Marasmus is due to deficiency of:

1. (a) Vitamin C
2. (b) Carbohydrates
3. (c) Fat
4. (d) Food

Question 4. 

Fat-soluble vitamins are

1. A, D and E
2. B, C and D
3. B, D and E
4. A, B and C

Question 5. 

Which of the following is the best source of Vitamin A?

1. Apple
2. Honey
3. Carrot
4. Peanuts

Question 6. 

Ascorbic acid is Vitamin:

1. C
2. D
3. B
4. A

Very short answer type

Question 1. 

1. Mention whether the following statement is true (T) or False (F).

Cellulose in our food passes out undigested.

True

False

2. Mention whether the following statement is true (T) or False (F). 

Kwashiorkor is a severe vitamin deficiency disease. 

True

False

3. Mention whether the following statement is true (T) or False (F). 

Iron is required for the proper working of the thyroid.

True

False

4. Mention Whether the Following Statement is True (T) Or False (F).

Foods protect us from disease and therefore antibiotics that protect us from the disease are also foods.

True

False

5. Mention whether the following statement is true (T) or False (F).

Mineral salts contribute in regulating body processes.

True

False

Ans:

Here are the evaluations for each statement:

1. True (T)
   • Reason: Humans lack the enzyme cellulase, which is necessary to break down cellulose (a complex carbohydrate found in plant cell walls). Cellulose acts as dietary fiber or roughage, aiding in bowel movements.
2. False (F)
   • Reason: Kwashiorkor is a severe protein deficiency disease, often combined with a deficiency of calories, but the primary pathology is related to a lack of protein.
3. False (F)
   • Reason: Iodine (not Iron) is the mineral required for the proper working of the thyroid gland, as it is essential for the synthesis of thyroid hormones. Iron is required for hemoglobin production.
4. False (F)
   • Reason: This is a logical fallacy. While foods provide nutrients that support the immune system, foods are substances that provide nutritional value. Antibiotics are drugs that kill bacteria and provide no nutritional value; therefore, they are not classified as food.
5. True (T)
   • Reason: Mineral salts (like sodium, potassium, calcium, etc.) are essential for numerous regulatory functions, including nerve impulse transmission, muscle contraction, fluid balance, and enzyme function.

Question 2. 

1. Name the mineral element that is needed for the following respectively:

Strong teeth 

2. Name the mineral element that is needed for the following respectively: 

Proper working of thyroid 

3. Name the mineral element that is needed for the following respectively: 

Synthesis of hemoglobin

Ans:

Here are the mineral elements needed for the respective biological functions:

1. Strong teeth: Calcium (and Phosphorus)
2. Proper working of thyroid: Iodine
3. Synthesis of hemoglobin: Iron

Question 3. 

1. Name the nutrients whose deficiencies cause the following diseases in humans:

Pernicious anemia

2. Name the nutrients whose deficiencies cause the following diseases in humans: Pellagra 

3. Deficiency of which vitamin causes night-blindness? 

4. Name the nutrients whose deficiencies cause the following diseases in humans: 

Goitre 

5. Name the nutrients whose deficiencies cause the following diseases in humans: 

Kwashiorkor

Ans:

Here are the nutrients whose deficiencies cause the specified diseases:

1. Pernicious anemia: Vitamin B12 (Cobalamin).
2. Pellagra: Vitamin B3 (Niacin).
3. Night-blindness: Vitamin A (Retinol).
4. Goitre: Iodine (a mineral element).
5. Kwashiorkor: Protein.

Question 4. 

1.Mark the odd one out in the following cases and name the category to which the others belong:  Xerophthalmia, Marasmus, Pellagra, Scurvy 

2. Mark the odd one out in the following cases and name the category to which the others belong: Riboflavin, Thiamine, Folic acid, Iodine

Ans:

Here are the odd ones out and the categories for each set:

1. Disease Classification 

• Odd One Out: Marasmus
• Category of Others: Vitamin Deficiency Diseases

Explanation

• Xerophthalmia, Pellagra, and Scurvy are all caused by a specific lack of a vitamin:
  • Xerophthalmia: Vitamin A deficiency
  • Pellagra: Niacin (Vitamin B3) deficiency
  • Scurvy: Vitamin C deficiency
• Marasmus is a severe form of protein-energy malnutrition (PEM), primarily caused by a deficiency of calories and protein, not just a single vitamin.

Nutrient Classification 

• Odd One Out: Iodine
• Category of Others: Vitamins

Explanation

• Riboflavin (Vitamin B2, Thiamine (Vitamin B1, and Folic acid (Vitamin B9 are all members of the essential nutrient group known as Vitamins.
• Iodine is an essential trace mineral (specifically required for the thyroid gland).

Short answer type

Question 1. 

1.Give two examples of the following and their usefulness, if any, in our body. Monosaccharides

2. Give two examples of the following and their usefulness, if any, in our body.

Disaccharides 

3. Give two examples of the following and their usefulness, if any, in our body. 

Polysaccharides

Ans:

Here are two examples and the usefulness of each type of carbohydrate in the human body.

1. Monosaccharides (Simple Sugars) 

Monosaccharides are the simplest form of sugar and serve as the fundamental source of cellular energy. Two key examples are Glucose and Fructose.

• Glucose: This is the most crucial monosaccharide. Its primary usefulness is acting as the direct, immediate fuel source for cellular respiration, especially for the brain and red blood cells. All digestible carbohydrates are ultimately broken down into glucose for transport and energy.
• Fructose: Found naturally in fruits and honey, Fructose is useful because it is converted into glucose in the liver. It provides a source of energy, and because it is slightly sweeter than glucose, it is often utilized in the food industry.

2. Disaccharides (Double Sugars) 

Disaccharides are formed when two monosaccharides are chemically joined. They must be broken down by enzymes before they can be absorbed and utilized for energy. Two examples are Sucrose and Lactose.

• Sucrose: Commonly known as table sugar, Sucrose is a compound of glucose and fructose. Its primary usefulness in the body is as an easily digested transport form of energy once broken down into its constituent monosaccharides.
• Lactose: This is the sugar found in milk, composed of glucose and galactose. Lactose is a vital source of energy and galactose (which is needed for synthesizing certain brain compounds) for infants and young mammals.

3. Polysaccharides (Complex Carbohydrates) 

Polysaccharides are long chains or polymers of monosaccharides. They function primarily as storage or structural compounds. Two important examples are Starch and Glycogen.

• Starch: Found in plants (like potatoes and grains), Starch is useful as the body’s major dietary source of energy. It is digested slowly, providing a sustained release of glucose into the bloodstream.
• Glycogen: This is often called “animal starch” because it is the primary energy storage carbohydrate in humans and animals. Glycogen is stored mainly in the liver and muscles, providing a readily available reserve of glucose that can be quickly mobilized during periods of fasting or intense exercise.

Question 2. 

Define and give one example of a balanced diet.

Ans:

Food Group	Example Serving	Nutrient Contribution
Fruits	One medium apple or a cup of berries.	Vitamins (especially C), minerals, antioxidants, and fiber.
Vegetables	Two cups of leafy greens (spinach, lettuce) and half a cup of carrots.	Vitamins (A, K), minerals, and high levels of dietary fiber.
Grains	One slice of whole-wheat bread and half a cup of brown rice.	Complex carbohydrates (energy), B vitamins, and fiber.
Protein Foods	3 ounces of lean chicken breast or a serving of lentils/beans.	Protein (for building and repair), iron, and B vitamins.
Dairy	One cup of skim milk or yogurt.	Calcium and Vitamin D (for bone health), and protein.

Question 3. 

A doctor advises a bone patient to include more milk and milk products in his everyday food. Why so?

Ans:

A doctor advises a bone patient to include more milk and milk products because these foods are the best dietary sources of calcium and often contain added Vitamin D .

The Role of Calcium and Vitamin D

• Calcium: This is the most essential mineral for bone health. Bones act as the body’s reservoir for calcium, giving them strength and rigidity. For a bone patient (such as one with a fracture, osteoporosis, or a condition affecting bone density), a high calcium intake is critical for:
  • Bone Repair and Remineralization: Supplying the building blocks necessary for the damaged bone tissue to heal and rebuild.
  • Maintaining Bone Density: Preventing further loss of bone mass.
• Vitamin D: Milk and fortified milk products often contain Vitamin D. While not a component of bone itself, Vitamin D is crucial because it enables the digestive tract to absorb calcium from the food you eat. Without adequate Vitamin D, even a high calcium intake would be largely ineffective.

Long answer type

Question 1. 

List the six main purposes for which food is required by the body.

Ans:

Food is essential for sustaining life and performing all bodily functions. Here are the six main purposes for which food is required by the human body:

1. Supply Energy (Fuel): Food, particularly carbohydrates and fats, is oxidized during respiration to release energy (ATP) required for all vital activities, including breathing, circulation, muscle movement, and maintaining body temperature.
2. Growth and Development: Proteins and minerals provide the building materials necessary for the formation of new cells, tissues, bones, and muscles, especially during childhood, adolescence, and pregnancy.
3. Repair and Maintenance: Food supplies the nutrients needed to replace worn-out or damaged cells and tissues, ensuring the body can constantly repair itself and maintain its structure throughout life.
4. Protection and Immunity: Vitamins (like C and D) and minerals (like Zinc) are essential for strengthening the immune system, enabling the body to fight off infections and diseases.
5. Regulation of Body Processes: Vitamins and mineral salts act as cofactors and regulators, ensuring that metabolic processes, nerve impulse transmission, fluid balance, and enzyme actions function correctly.
6. Storage: Excess nutrients, particularly carbohydrates and fats, are converted and stored (as glycogen in the liver and muscles, or as fat in adipose tissue) to serve as energy reserves during periods of fasting or high demand.

Question 2. 

Why are proteins necessary in our food? Name one protein deficiency disease of young children.

Ans:

Proteins are absolutely essential in our food because they are the fundamental building blocks and operational molecules for nearly every structure and function in the body.

Why Proteins are Necessary

Proteins are large, complex molecules made up of amino acids, and their roles are multifaceted:

1. Building and Repair (Structural Role): Proteins are the primary component of all body tissues, including muscles, bones, hair, skin, and nails. They are vital for growth in children and for the repair and maintenance of worn-out cells and tissues throughout life.
2. Enzymes and Hormones (Functional Role): Almost all enzymes, which catalyze (speed up) biochemical reactions in the body (like digestion and metabolism), are proteins. Many essential hormones (like insulin) that regulate body processes are also proteins.
3. Transport and Defense: Proteins are used to transport substances through the blood (e.g., hemoglobin transports oxygen). They also form antibodies (immunoglobulins) that protect the body against foreign pathogens, serving a crucial role in the immune system.
4. Fluid Balance: Proteins help maintain the proper distribution of water between blood and body tissues.

Protein Deficiency Disease

One protein deficiency disease commonly seen in young children is Kwashiorkor.

• This disease results from a severe lack of protein intake (often when a child is weaned onto a carbohydrate-rich, but protein-poor, diet).
• It is characterized by edema (swelling, particularly in the legs and abdomen), muscle wasting, and delayed growth.

Question 3. 

Taking the examples of whole grain atta, fruit and green leafy vegetables, describe how roughage in our diet is useful.

Ans:

Roughage, also known as dietary fiber, is the undigested portion of plant-based food that is essential to a healthy diet.

Taking the examples of whole grain atta, fruit, and green leafy vegetables, here is how roughage is useful in our body:

1. Whole Grain Atta (Cereal Fibers) 

Whole grain atta (flour) contains the outer layers of the grain (bran and germ), which are rich in insoluble fiber.

• Usefulness: This type of roughage is crucial for aiding peristalsis (the rhythmic contractions of the intestine). It adds bulk to the stool, which helps it move quickly and smoothly through the digestive tract. This quick transit time is essential for preventing constipation and reducing the time toxins remain in contact with the intestinal walls.

2. Fruit (Soluble and Insoluble Fibers) 

Fruits (especially their skins, seeds, and pulp) contain both insoluble fiber (like the skin of an apple) and soluble fiber (like pectin).

• Usefulness: Soluble fiber dissolves in water to form a gel-like substance. This is useful because it helps slow down the absorption of glucose into the bloodstream, which helps regulate blood sugar levels. It also helps lower blood cholesterol by binding to cholesterol particles in the gut, preventing their absorption.

3. Green Leafy Vegetables (Cellulose) 

Green leafy vegetables are rich in cellulose, which is an insoluble structural fiber found in plant cell walls.

• Usefulness: This fiber adds significant volume and softness to the fecal matter. While humans cannot digest it, its bulk stimulates the muscles of the large intestine, promoting regular bowel movements. This mechanical stimulation and bulking action help prevent hemorrhoids and diverticulosis.

Structured/Application/Skill type

Question 1.

Given alongside is an incomplete table of vitamins, their rich sources and the related deficiency diseases. Fill in the blanks [(i)-(viii)] with only one suitable word for each. 

VITAMIN	RICH SOURCE	DEFICIENCY DISEASE
(i) _________	Whole grain	Beri-beri
Niacin	Milk	(ii) __________
(iii) __________	(iv) _________	Scurvy
Calciferol	(v) _________	(vi) __________
(vii) ___________	Carrot, yellow fruit	(viii)  __________

Ans:

VITAMIN	RICH SOURCE	DEFICIENCY DISEASE
(i) Thiamine (B1​)	Whole grain	Beri-beri
Niacin (B3​)	Milk	(ii) Pellagra
(iii) Ascorbic acid (C)	(iv) Citrus fruits	Scurvy
Calciferol (D)	(v) Sunlight	(vi) Rickets
(vii) Retinol (A)	Carrot, yellow fruit	(viii) Night blindness

Question 2. 

Complete the following table by filling the blanks:

Mineral	Function	Rich Source
Iodine	__________	__________
__________	Formation of haemoglobin	__________
Calcium	__________	__________
Potassium	__________	__________

Ans:

Mineral	Function	Rich Source
Iodine	Essential for the synthesis of thyroid hormones (which regulate metabolism and growth).	Iodized salt, seafood (fish, shellfish), and dairy products.
Iron	Formation of haemoglobin (protein in red blood cells that transports oxygen).	Red meat (e.g., liver), dried beans/lentils, green leafy vegetables (e.g., spinach), and fortified cereals.
Calcium	Builds and maintains strong bones and teeth; aids in blood clotting, muscle contraction, and nerve function.	Milk and milk products (cheese, yogurt), leafy greens (e.g., kale), and small fish with bones (e.g., sardines).
Potassium	Helps maintain fluid and electrolyte balance; essential for muscle contraction (including heart) and nerve function.	Bananas, potatoes, citrus fruits, leafy green vegetables, and legumes.