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🔬🌈 Biochemistry (Chapter # 4) MasterClass for X Students | Model Test Questions 2027 | High-Score Booster Guide
🔥📘 Short Questions
Q1. What is vitamin A and vitamin D? Describe the sources and uses of vitamin A and vitamin D. Write deficiency disease arises due to of following Vitamins:
(i) Vitamin A
(ii) Vitamin D
(iii) Vitamin E
(iv) Vitamin K
(v) Vitamin C
Q2. What are enzymes. Write one use of the following enzymes:
(i) Yeast (ii) Cellulase (iii) Amylase (iv) lactase (v) lipase (vi) Protease
Q3. Differentiate between
(i) Dextrorotary and Levorotatory Sugars
(ii) fats and oils
(iii) fat and water-soluble vitamins.
Q4. Define biochemistry. Enumerate the important uses of carbohydrates. How do plants synthesize carbohydrates? Give equation of preparation.
Q5. What are Oligosaccharides and Disaccharides. Give their examples and sources.
Q6. What are polysaccharides? Give their examples. How monosaccharides are produced from polysaccharides?
Q7. What are proteins? Give their importance and sources.
Q8. What is peptide bond (Peptide linkage)? Describe the formation of dipeptide through peptide linkage bond between two amino acid units with structural equation. Also explain dipeptides and tripeptides.
Q9. What are amino acids and give their general structure? How many Essential and Non-essential Amino acids are there? Write down the range of Number of Amino acids and molecular weights of Proteins
Q10. What are fatty acids? Give their examples and chemical nature. Define saponification
Q11. Explain Hydrogenation of vegetable oil into vegetable ghee.
🔥📘Detailed Questions
Q1. What are the carbohydrates? Differentiate between aldoses and ketoses. Explain sources and types of carbohydrates.
Q2. What are lipids? Write down the sources and uses of lipids.
Q3. Describe vitamins and types of vitamins. Justify that water soluble vitamins are not injurious to health.
Q4. Describe in detail nucleic acids, RNA and DNA. OR What are nucleic acids? Give importance of Nucleic Acid. Write down importance of deoxyribonucleic acid (DNA). Compare the structural, functional and chemical differences between DNA and RNA.
Q5. How you can justify that deficiency of different types of vitamins causes diseases in human beings?
🧪⚡Answers of Short Questions Chemistry Model Questions Test # 1 X Chapter # 4 Biochemistry
🌟💥 Short Questions🧪📚
Q1. What is vitamin A and vitamin D? Describe the sources and uses of vitamin A and vitamin D. Write deficiency disease arises due to of following Vitamins:
(i) Vitamin A(ii) Vitamin D
(iii) Vitamin E
(iv) Vitamin K
(v) Vitamin C
Answer
Definition of Vitamin A (Anti-xerophthalmic Vitamin):
Vitamin A (Retinol) is a fat-soluble vitamin that is essential for vision, growth, healthy skin, and immunity.
Sources:
➡️Liver, Butter, fish, eggs, milk, cheese
➡️Carrots and green/yellow vegetables, Vitamin A can also be obtained from β-carotene.
Uses / Importance:
➡️Essential for normal vision and formation of visual pigments.
➡️Helps maintain healthy skin.
➡️Deficiency causes night blindness, xerophthalmia, dry skin, and eye inflammation.
Definition of Vitamin D:
Vitamin D (Antirachitic Vitamin) is a fat-soluble vitamin that helps maintain healthy bones and teeth.
Sources of Vitamin D:
➡️Fish liver oil, Oils and fats, Milk and dairy products, Mushrooms
➡️Sunlight — helps the skin synthesize Vitamin D
Importance of Vitamin D:
➡️Helps in the absorption and metabolism of calcium and phosphorus.
➡️Essential for strong bones and teeth.
➡️Deficiency causes rickets in children.
🟠 Vitamin A — Retinol 🥕⚠️ Deficiency: Night blindness, xerophthalmia, dry skin
🟡 Vitamin D — Calciferol ☀️⚠️ Deficiency: Rickets
🟢 Vitamin E — Tocopherol 🌰 ⚠️ Deficiency: Sterility, haemolysis
🔵 Vitamin K — Phylloquinone 🥬⚠️ Deficiency: Haemorrhage
🔴 Vitamin C — Ascorbic acid 🍊 ⚠️ Deficiency: Scurvy
Q2. What are enzymes. Write one use of the following enzymes:
(i) Yeast (ii) Cellulase (iii) Amylase (iv) lactase (v) lipase (vi) Protease
Answer
Definition of Enzymes
Enzymes are biological catalysts, mostly proteins, that speed up biochemical reactions in living organisms without being consumed in the reactions.
Uses of Enzymes
1. Yeast (Alcohol Production / Fermentation)
➡️Yeast contains enzymes such as zymase, invertase and maltase.
➡️These enzymes convert sugars into ethanol (alcohol) and carbon dioxide during fermentation.
➡️Used in the production of alcoholic beverages and industrial ethanol.
2. Cellulase (Detergents and Textile Industry)
➡️Breaks down cellulose into simpler sugars.
➡️Used in detergents to remove plant-based stains and improve fabric cleaning.
3. Amylase (Baking Industry)
➡️Breaks down starch into simpler sugars.
➡️Used in bread-making to improve dough fermentation, bread texture and volume.
4. Lactase (Dairy Industry)
➡️Breaks down lactose (milk sugar) into glucose and galactose.
➡️Used to produce lactose-free milk and ice cream.
5. Lipase (Detergent Industry)
➡️Breaks down fats and oils into fatty acids and glycerol.
➡️Used in detergents to remove greasy and oily stains.
6. Protease (Detergent Industry)
➡️Breaks down proteins into smaller peptides and amino acids.
➡️Used in detergents to remove protein-based stains such as blood, egg and food stains.
Q3. Differentiate between
(i) Dextrorotary and Levorotatory Sugars
(ii) fats and oils
(iii) fat and water-soluble vitamins.
Answer
🧬 Biochemistry
Biochemistry is the branch of chemistry that deals with the chemical substances and processes occurring in living organisms.
Uses of carbohydrates
1. Energy Source: Main source of energy in humans and animals; glucose is directly used by cells for energy.
2. Plant Structure: Cellulose provides structural support to plants.
3. Energy Storage: Starch in plants and glycogen in animals store energy.
4. Blood Glucose: Maintain blood glucose levels; glucose is essential for normal brain function.
5. Food Industry: Sucrose is widely used as a sweetener and food additive in jams, jellies, confectionery, etc.
6. Dietary Fibre: Cellulose and other fibres add bulk to food and help maintain normal intestinal movement.
7. Biomolecules: Carbohydrates occur in combination with proteins and lipids in living organisms.
8. Industrial Uses: Cellulose is used in the paper and textile industries, while starch is used in paper coating, laundry, and ethanol production.
☀️ Photosynthesis
Plants synthesize glucose (a carbohydrate) from carbon dioxide and water in the presence of sunlight and chlorophyll. The glucose produced may be converted into starch for storage and cellulose for plant structure.
Overall Equation: 6CO₂ + 6H₂O —(Sunlight | Chlorophyll)⟶ C₆H₁₂O₆ + 6O₂
Q5. What are Oligosaccharides and Disaccharides. Give their examples and sources.
Answer
Oligosaccharides (Oligo = few; saccharide = sugar)
Oligosaccharides are carbohydrates that yield 2–10 monosaccharide units on hydrolysis, joined by glycosidic linkages.
General equation: Oligosaccharide + water —(hydrolysis) ⟶ 2–10 monosaccharide units
Example: C₁₂H₂₂O₁₁ + H₂O —(hydrolysis) ⟶ C₆H₁₂O₆ (glucose) + C₆H₁₂O₆ (fructose)
Disaccharides (Di = two; saccharide = sugar)
Disaccharides are oligosaccharides that contain two monosaccharide units. On hydrolysis, they produce two monosaccharides (one unit of glucose and one unit of fructose).
Examples
Sucrose, maltose, lactose are important members of disaccharides.
Examples & Sources
Examples & Sources
1. Cellulose: Found in plant cell walls, wood, cotton, linen, and paper. Cotton contains about 90–95% cellulose.
2. Starch: Found mainly in wheat, rice, barley, and potatoes. It is the main storage carbohydrate in plants.
3. Glycogen: Known as animal starch. It is stored mainly in the liver and muscles of animals.
Q7. What are proteins? Give their importance and sources.
Answer
Importance & Functions
1. Growth & Repair: Help in growth and repair of body tissues.
2. Enzymes: Act as biological catalysts in biochemical reactions, as drugs in pharmaceuticals. They control the bleeding and treat blood cancer.
3. Structure: Keratin and collagen provide strength and structure.
4. Gelatin: Used in food and bakery products (Collagen → Gelatin (on heating with water)
5. Leather: Protein-rich hides are used to make leather products.
6. Defense: Some proteins, such as antibodies, protect the body.
7. Transport: Proteins help transport substances in the body.
Sources of Proteins
Animal Sources: Meat, chicken, fish, eggs, milk, and cheese.
Plant Sources: Pulses, beans, peas, nuts, and other legumes.
Peptide Bond: An amide bond (–CO–NH–) formed between two amino acids by elimination of H₂O.
Formation: The –COOH group reacts with the –NH₂ group of amino acids, releasing H₂O to form peptide bond
Dipeptide: A molecule formed by the joining of two amino acids through a peptide bond.
Tripeptide: A molecule formed by the joining of three amino acids through peptide bonds.
Protein: A polypeptide chain containing many amino acids linked by peptide bonds.
General Equation: Amino acid + Amino acid → Dipeptide + H₂O
Structural Equation: H₂N–CHR–COOH + H₂N–CHR′–COOH → H₂N–CHR–CO–NH–CHR′–COOH + H₂O
Here, –CO–NH– is the peptide bond.
Definition: Amino acids are the building blocks of proteins containing an acidic –COOH and a basic –NH₂ groups
General Structure: H₂N–CH(R)–COOH
R = Side chain, which differs from one amino acid to another.
Essential & Non-essential Amino Acids:
Total = 20 amino acids.
10 Essential amino acids — must be obtained from diet.
10 Non-essential amino acids — can be synthesized by the body.
Number of Amino acids and molecule weight in Proteins
Number of Amino Acids:
Proteins may contain 60–6000 amino acid residues.
Molecular Weight:
Protein molecular weight generally ranges from 43,000–50,000,000 daltons (Da).
📌 1 Dalton (Da) = 1 atomic mass unit (amu).
Definition:
Examples:
Palmitic acid: C₁₅H₃₁COOH
Stearic acid: C₁₇H₃₅COOH
Importance
Fatty acids form esters (oils or fats) and glycerol in the presence of mineral acids.
Chemical Nature:
General Structure:
Glycerol + 3 Fatty acids → Triglyceride + 3H₂O
Saponification
Q11. Explain Hydrogenation of vegetable oil into vegetable ghee.
Answer
Definition:
Conditions:
Catalyst: Ni or Pd
Temperature: 250–300°C
Nature of Reaction:
It is an addition reaction in which H₂ adds across the C=C double bonds of unsaturated fatty acids, forming saturated fatty acids.
General Equation:
Answer
📌 Carbohydrates — Definition, Difference, Types & Sources
Definition:
📌 Difference Between Aldoses and Ketoses
✨Aldoses
1. Contain an aldehyde group (–CHO).
2. Carbonyl group is present at the end of the carbon chain.
3.Usually have the carbonyl group at C-1.
4. Example: Glucose, Ribose.
✨Ketoses
1.Contain a ketone group (>C=O).
2.Carbonyl group is usually present within the carbon chain.
3.Usually have the carbonyl group at C-2.
4.Example: Fructose, Ribulose.
📌 Classification Based on Hydrolysis
Answer
Q4. Define biochemistry. Enumerate the important uses of carbohydrates. How do plants synthesize carbohydrates? Give equation of preparation.
Answer🧬 Biochemistry
Biochemistry is the branch of chemistry that deals with the chemical substances and processes occurring in living organisms.
Uses of carbohydrates
1. Energy Source: Main source of energy in humans and animals; glucose is directly used by cells for energy.
2. Plant Structure: Cellulose provides structural support to plants.
3. Energy Storage: Starch in plants and glycogen in animals store energy.
4. Blood Glucose: Maintain blood glucose levels; glucose is essential for normal brain function.
5. Food Industry: Sucrose is widely used as a sweetener and food additive in jams, jellies, confectionery, etc.
6. Dietary Fibre: Cellulose and other fibres add bulk to food and help maintain normal intestinal movement.
7. Biomolecules: Carbohydrates occur in combination with proteins and lipids in living organisms.
8. Industrial Uses: Cellulose is used in the paper and textile industries, while starch is used in paper coating, laundry, and ethanol production.
☀️ Photosynthesis
Plants synthesize glucose (a carbohydrate) from carbon dioxide and water in the presence of sunlight and chlorophyll. The glucose produced may be converted into starch for storage and cellulose for plant structure.
Overall Equation: 6CO₂ + 6H₂O —(Sunlight | Chlorophyll)⟶ C₆H₁₂O₆ + 6O₂
Q5. What are Oligosaccharides and Disaccharides. Give their examples and sources.
Answer
Oligosaccharides (Oligo = few; saccharide = sugar)
Oligosaccharides are carbohydrates that yield 2–10 monosaccharide units on hydrolysis, joined by glycosidic linkages.
General equation: Oligosaccharide + water —(hydrolysis) ⟶ 2–10 monosaccharide units
Example: C₁₂H₂₂O₁₁ + H₂O —(hydrolysis) ⟶ C₆H₁₂O₆ (glucose) + C₆H₁₂O₆ (fructose)
Disaccharides (Di = two; saccharide = sugar)
Disaccharides are oligosaccharides that contain two monosaccharide units. On hydrolysis, they produce two monosaccharides (one unit of glucose and one unit of fructose).
Examples
Sucrose, maltose, lactose are important members of disaccharides.
Examples & Sources
Sucrose/Cane/Table sugar: Glucose + Fructose → Sugarcane, sugar beet, beet root, carrots, maple, pineapple etc
Lactose/(milk sugar): Glucose + Galactose → Milk
Maltose/Malt sugar: Glucose + Glucose → Wheat(گندم) , barley(جو)
Raffinose (a trisaccharide; Galactose + Glucose + Fructose) is an oligosaccharide found in legumes, vegetables. Q6. What are polysaccharides? Give their examples. How monosaccharides are produced from polysaccharides?
AnswerDefinition
Polysaccharides are complex polymeric carbohydrates that yield more than 10 monosaccharide units on hydrolysis. Their units are joined by glycosidic linkages.
General equation: Oligosaccharide + water —(hydrolysis)⟶ More than 10 monosaccharide units
Example: (C₆H₁₀O₅)ₙ (starch) + H₂O —(hydrolysis)⟶ nC₆H₁₂O₆ (glucose)
Examples & Sources
1. Cellulose: Found in plant cell walls, wood, cotton, linen, and paper. Cotton contains about 90–95% cellulose.
2. Starch: Found mainly in wheat, rice, barley, and potatoes. It is the main storage carbohydrate in plants.
3. Glycogen: Known as animal starch. It is stored mainly in the liver and muscles of animals.
Q7. What are proteins? Give their importance and sources.
Answer
Definition of Proteins (Greek ‘Proteios’ means ‘first’)
Proteins are complex nitrogen-containing macromolecules (polymers) made up of amino acids (monomers) linked by peptide linkages. They are essential components of all living cells and yield amino acids on hydrolysis.
Proteins make up more than 50% of the dry weight of animals.
Importance & Functions
1. Growth & Repair: Help in growth and repair of body tissues.
2. Enzymes: Act as biological catalysts in biochemical reactions, as drugs in pharmaceuticals. They control the bleeding and treat blood cancer.
3. Structure: Keratin and collagen provide strength and structure.
4. Gelatin: Used in food and bakery products (Collagen → Gelatin (on heating with water)
5. Leather: Protein-rich hides are used to make leather products.
6. Defense: Some proteins, such as antibodies, protect the body.
7. Transport: Proteins help transport substances in the body.
Sources of Proteins
Animal Sources: Meat, chicken, fish, eggs, milk, and cheese.
Plant Sources: Pulses, beans, peas, nuts, and other legumes.
Q8. What is peptide bond (Peptide linkage)? Describe the formation of dipeptide through peptide linkage bond between two amino acid units with structural equation. Also explain dipeptides and tripeptides.
AnswerPeptide Bond: An amide bond (–CO–NH–) formed between two amino acids by elimination of H₂O.
Formation: The –COOH group reacts with the –NH₂ group of amino acids, releasing H₂O to form peptide bond
Dipeptide: A molecule formed by the joining of two amino acids through a peptide bond.
Tripeptide: A molecule formed by the joining of three amino acids through peptide bonds.
Protein: A polypeptide chain containing many amino acids linked by peptide bonds.
General Equation: Amino acid + Amino acid → Dipeptide + H₂O
Structural Equation: H₂N–CHR–COOH + H₂N–CHR′–COOH → H₂N–CHR–CO–NH–CHR′–COOH + H₂O
Here, –CO–NH– is the peptide bond.
Q9. What are amino acids and give their general structure? How many Essential and Non-essential Amino acids are there? Write down the range of Number of Amino acids and molecular weights of Proteins
AnswerDefinition: Amino acids are the building blocks of proteins containing an acidic –COOH and a basic –NH₂ groups
General Structure: H₂N–CH(R)–COOH
R = Side chain, which differs from one amino acid to another.
Essential & Non-essential Amino Acids:
Total = 20 amino acids.
10 Essential amino acids — must be obtained from diet.
10 Non-essential amino acids — can be synthesized by the body.
Number of Amino acids and molecule weight in Proteins
Number of Amino Acids:
Proteins may contain 60–6000 amino acid residues.
Molecular Weight:
Protein molecular weight generally ranges from 43,000–50,000,000 daltons (Da).
📌 1 Dalton (Da) = 1 atomic mass unit (amu).
Q10. What are fatty acids? Give their examples and chemical nature. Define saponification
AnswerDefinition:
Fatty acids are long-chain saturated or unsaturated carboxylic acids that are important building blocks of lipids.
Examples:
Palmitic acid: C₁₅H₃₁COOH
Stearic acid: C₁₇H₃₅COOH
Importance
Fatty acids form esters (oils or fats) and glycerol in the presence of mineral acids.
Chemical Nature:
Fats and oils are triesters of glycerol and long-chain fatty acids, called triglycerides.
General Structure:
Glycerol + 3 Fatty acids → Triglyceride + 3H₂O
Saponification
The alkaline hydrolysis of fats or oils with NaOH or KOH to produce soap and glycerol is called saponification.
Q11. Explain Hydrogenation of vegetable oil into vegetable ghee.
Answer
Definition:
Hydrogenation is the process of converting unsaturated vegetable oil into saturated fat (ghee) by adding H₂.
Conditions:
Catalyst: Ni or Pd
Temperature: 250–300°C
Nature of Reaction:
It is an addition reaction in which H₂ adds across the C=C double bonds of unsaturated fatty acids, forming saturated fatty acids.
General Equation:
Unsaturated Vegetable oil + H₂ → Saturated Vegetable fat (ghee)
🧪⚡Answers of Long Questions Chemistry Model Questions Test # 1 X Chapter # 4 Biochemistry
🌟💥 Long Questions🧪📚
Q1. What are the carbohydrates? Differentiate between aldoses and ketoses. Explain sources and types of carbohydrates.Answer
📌 Carbohydrates — Definition, Difference, Types & Sources
Definition:
Carbohydrates are naturally occurring organic compounds containing mainly C, H and O. They are polyhydroxy aldehydes or ketones, or compounds that produce them on hydrolysis.
General Formula: Cₙ(H₂O)ₙ
H:O ratio is generally 2:1, but carbohydrates do not actually contain water molecules.
✨Aldoses
1. Contain an aldehyde group (–CHO).
2. Carbonyl group is present at the end of the carbon chain.
3.Usually have the carbonyl group at C-1.
4. Example: Glucose, Ribose.
✨Ketoses
1.Contain a ketone group (>C=O).
2.Carbonyl group is usually present within the carbon chain.
3.Usually have the carbonyl group at C-2.
4.Example: Fructose, Ribulose.
📌 Classification Based on Hydrolysis
✨Monosaccharides (Greek; Mono = one)
Definition: Simplest carbohydrates; cannot be hydrolyzed further.
Equation: Monosaccharides + water —(Hydrolysis)→ No reaction
Example: C₆H₁₂O₆ + water —(Hydrolysis)→ No reaction
No of Carbon atoms : Usually contain 3–10 carbon atoms.
Properties: Generally sweet, crystalline and water-soluble, reducing in nature (reducing sugars).
Molecular formula of Hexose sugars: Both have formula C₆H₁₂O₆.
Types Based on the number of carbon atoms: trioses, tetroses, pentoses, hexoses, and so on.
Examples of Hexoses: Glucose, Fructose
Glucose: aldohexose/ pentahydroxy aldehyde; found in grapes (grape sugar; (20-30%)), honey and blood.
Fructose: ketohexose/ pentahydroxy ketone; found in fruits, honey and cane sugar etc.
Normal blood glucose (blood sugar): 65-110 mg (0.06-0.1%) per 100 mL.
Glucose optical rotation: dextrorotatory
✨Oligosaccharides (Greek; Oligo = few)
➡️Definition: Produce 2–10 monosaccharide units on hydrolysis. Units are linked by glycosidic linkages.
➡️Equation: Oligosaccharides + water —(Hydrolysis)→ 2–10 monosaccharide units
➡️ Example: C₁₂H₂₂O₁₁(sucrose) + water —(Hydrolysis)→ C₆H₁₂O₆ (glucose)+ C₆H₁₂O₆ (glucose)
➡️ Properties: Generally white, sweet, crystalline and water-soluble, may be reducing or non-reducing
➡️ Types Based on the number of monosaccharides units: disaccharides, trisaccharides, tetrasaccharides etc.
➡️ Disaccharides: contain two monosaccharide units.
➡️ Examples of Disaccharides: Sucrose, Lactose, Maltose, Raffinose.
Sucrose (Table sugar) → Glucose + Fructose
Lactose (milk sugar) → Glucose + Galactose
Maltose (Malt sugar) → Glucose + Glucose
✨Polysaccharides
➡️Definition: Produce more than 10 monosaccharide units on hydrolysis. Consist of many monosaccharide units linked by glycosidic linkages.
➡️Equation: Polysaccharides + water —(Hydrolysis)→ more than 10 monosaccharide units
➡️ Example: (C₆H₁₁O₅)ₙ (cellulose or starch) + water —(Hydrolysis)→ nC₆H₁₂O₆ (glucose)
➡️ Properties: Generally tasteless, amorphous and insoluble in water.
➡️ Examples: Starch (plant origin), Cellulose(plant origin), Glycogen (animal origin)
Starch: wheat, rice, barley, potatoes.
Cellulose: plant cell walls, cotton, wood, linen. Cotton contains 95% cellulose.
Glycogen: stored in liver and muscles; called animal starch.
📌 Sources of Carbohydrates
➡️Monosaccharide: Glucose, Fructose; Major Sources: Grapes, honey, fruits
➡️Oligosaccharides: Sucrose; Major Sources: Sugarcane, sugar beet, beet root, carrots, maple, pineapple etc.
➡️Oligosaccharides: Lactose; Major Sources: Milk
➡️Oligosaccharides: Maltose; Major Sources: Wheat, barley
➡️Oligosaccharides: Raffinose; Major Sources: Legumes
➡️Polysaccharides: Cellulose; Major Sources: Cell of all land plants, cotton etc.
➡️Polysaccharides: Starch; Major Sources: Cereal foods (wheat, barley), potato etc.
➡️Polysaccharides: Glycogen; Major Sources: Liver, muscles etc. (animal starch)
Q2. What are lipids? Write down the sources and uses of lipids.
Answer
📌 Definition:
Lipids are naturally occurring heterogeneous organic compounds including fats, oils and waxes. They are insoluble in water but soluble in organic solvents such as ether, benzene, acetone and chloroform and in Bloor’s reagent (mixture of diethyl ether and ethyl alcohol in the ratio of 2:1). Lipids are the building blocks of cells.
📌 Constituent Elements:
Mainly C, H and O; some lipids also contain N and P.
📌 Sources of Lipids
➡️Animal Sources: Butter, ghee and cheese, Fish such as salmon, Marine animals such as whales
➡️Plant Sources: Sunflower, Coconut, Groundnuts, Corn, Cottonseed, Olive
📌 Uses of Lipids
➡️Help transport fat-soluble vitamins A, D, E and K.
➡️Used for cooking and frying foods.
➡️Used in soaps, detergents and cosmetics.
➡️Used in polishes and paints.
➡️Serve important structural and functional roles in cells.
➡️Animal fats are used to prepare butter, ghee, bakery products and sweets.
Q3. Describe vitamins and types of vitamins. Justify that water soluble vitamins are not injurious to health.
Answer🧪 1. Vitamins (Introduction)
Discovery: In 1912, Frederick Gowland Hopkins discovered that, besides carbohydrates, proteins and fats, other nutrients are essential for normal growth and health. He called them Accessory Growth Factors.
Naming: Later, Casimir Funk (1912) introduced the term Vitamin and identified vitamin B₁ (Thiamine).
Definition: Vitamins are organic compounds required in small quantities for normal growth, metabolism and good health.
Importance: They regulate various body functions and help prevent deficiency diseases.
🔬 2. Types of Vitamins (Based on Solubility)
Vitamins are classified into two main types:
(i) Water-Soluble Vitamins 💧
Definition: Vitamins that dissolve in water are called water-soluble vitamins.
Types: Vitamin B-complex (this include 10/8 vitamins) and Vitamin C (Ascorbic acid).
Sources: Cereals, fruits, vegetables, milk, meat and eggs.
Storage: Generally, they are not stored in significant amounts in the body (except vitamin B₁₂, which can be stored).
Excretion: Excess amounts are generally excreted through urine.
Toxicity: They have a lower risk of toxicity because excess amounts are usually eliminated from the body.
📌 Why are water-soluble vitamins generally not injurious to health?
Water-soluble vitamins dissolve in water and their excess amounts are generally excreted through urine. Therefore, they are less likely to accumulate in the body and cause toxicity. However, excessive intake of some water-soluble vitamins can still cause adverse effects.
(ii) Fat-Soluble Vitamins 🥑
Definition: Vitamins that dissolve in fats and organic solvents are called fat-soluble vitamins.
Types: Vitamins A, D, E and K.
Sources: Butter, milk, eggs, fish, liver, vegetable oils and green leafy vegetables.
Storage: They are stored in the liver and fatty tissues of the body.
Toxicity: Excessive intake may cause toxicity because they accumulate in the body.
Examples of toxicity:
Vitamin A: Excess may cause headache, nausea and other health problems.
Vitamin D: Excess may cause calcium accumulation in the blood and deposits in kidneys.
Vitamin E: Excessive intake may increase the risk of bleeding.
Vitamin K: Excessive intake of synthetic forms may cause harmful effects.
📚 Sources, Functions and Deficiency Diseases of Vitamins
(A) Fat-Soluble Vitamins
1. Vitamin A (Retinol) 👁️
Sources: Liver, fish liver oil, milk, butter, eggs, cheese, carrots and green leafy vegetables (beta-carotene).
Importance: Essential for vision, healthy skin and normal growth.
Deficiency: Night blindness, xerophthalmia (dryness of eyes), dry skin and eye damage.
2. Vitamin D (Calciferol / Antirachitic Vitamin) ☀️
Sources: Sunlight (synthesis in skin), fish liver oil, eggs, milk and butter.
Importance: Helps in the absorption of calcium and phosphorus and maintains healthy bones and teeth.
Deficiency: Rickets in children and osteomalacia (softening of bones) in adults.
3. Vitamin E (Tocopherol) 🛡️
Sources: Vegetable oils, wheat germ oil, sunflower seeds, nuts and green leafy vegetables.
Importance: Acts as an antioxidant and protects cell membranes from damage.
Deficiency: Muscle weakness, nerve problems and haemolytic anaemia (especially in premature infants).
4. Vitamin K (Phylloquinone) 🩸
Sources: Spinach, cabbage, broccoli, other green leafy vegetables and intestinal bacteria.
Importance: Essential for the formation of blood-clotting factors.
Deficiency: Haemorrhage (excessive bleeding) due to delayed blood clotting.
(B) Water-Soluble Vitamins
5. Vitamin B-Complex ⚡
Sources: Whole grains, cereals, meat, eggs, milk, liver, nuts and yeast.
Importance: Helps in energy metabolism, normal nerve functioning, red blood cell formation and healthy skin.
Deficiency: Depending on the particular B vitamin, deficiency may cause:
B₁ (Thiamine): Beriberi.
B₂ (Riboflavin): Cracked lips, sore tongue and dermatitis.
B₃ (Niacin): Pellagra (dermatitis, diarrhoea and dementia).
B₆ (Pyridoxine): Anaemia and nerve problems.
B₉ (Folic acid): Megaloblastic anaemia.
B₁₂ (Cobalamin): Megaloblastic anaemia and nerve damage.
6. Vitamin C (Ascorbic Acid) 🍊
Sources: Oranges, lemons, guava, tomatoes, green peppers and other fresh fruits and vegetables.
Importance: Helps in wound healing, collagen formation, healthy gums and iron absorption.
Deficiency: Scurvy (bleeding gums, poor wound healing and reopening of old wounds).
Q4. Describe in detail nucleic acids, RNA and DNA. OR What are nucleic acids? Give importance of Nucleic Acid. Write down importance of deoxyribonucleic acid (DNA). Compare the structural, functional and chemical differences between DNA and RNA.
Answer🔹 Definition:
Nucleic acids are biopolymers made up of nucleotides. They include DNA and RNA.
Each nucleotide consists of:
🧪 Nitrogenous base
🍬 Pentose sugar
⚡ Phosphate group
🔬 Importance of Nucleic Acids
🧬 Genetic Information: Store genetic information.
🔄 Heredity: Transfer hereditary information from one generation to another.
🧫 Cell Function: Control and support important cellular activities.
🧪 Protein Synthesis: Direct the synthesis of proteins.
⚡ Energy: ATP, a nucleotide, serves as an important energy carrier in cells.
🧬 Importance of DNA
Stores genetic information.
Transfers hereditary information from parents to offspring.
Controls protein synthesis and cellular activities.
Provides instructions for growth and development.
1. Ribonucleic Acid (RNA)
Sugar: Contains ribose sugar (C₅H₁₀O₅).
Structure: Usually a single-stranded molecule.
Nitrogenous Bases: Contains four bases: Adenine (A), Guanine (G), Cytosine (C) and Uracil (U).
Formation: Synthesized from DNA by a process called transcription.
Function: Carries, reads and uses genetic instructions to direct protein synthesis.
Role: Acts as a messenger and functional molecule in gene expression.
Types: Three major types are:
mRNA (Messenger RNA): Carries genetic instructions from DNA to ribosomes.
tRNA (Transfer RNA): Transfers amino acids to ribosomes.
rRNA (Ribosomal RNA): Forms part of ribosomes and helps in protein synthesis.
2. Deoxyribonucleic Acid (DNA)
Sugar: Contains deoxyribose sugar (C₅H₁₀O₄).
Structure: Consists of two long polynucleotide strands arranged in a double helix.
Nitrogenous Bases: Contains four bases: Adenine (A), Guanine (G), Cytosine (C) and Thymine (T).
Discovery: The double-helix model was proposed by James Watson and Francis Crick in 1953, based partly on the experimental work of Rosalind Franklin and Maurice Wilkins.
Composition: Each strand consists of repeating nucleotides containing sugar, phosphate and a nitrogenous base.
Backbone: Sugar and phosphate groups form the outer backbone, while nitrogenous bases face inward.
Base Pairing: The two strands are held together by hydrogen bonds:
A pairs with T through two hydrogen bonds.
G pairs with C through three hydrogen bonds.
Function: Stores and transmits hereditary information from one generation to the next.
Genetic Code: The sequence of nitrogenous bases contains instructions for making proteins and controlling cellular activities.
Replication: DNA makes identical copies of itself through a process called replication before cell division.
Gene Expression: DNA contains genes that provide instructions for synthesizing RNA and, indirectly, proteins.
Importance: Changes (mutations) in DNA may produce altered proteins and can sometimes cause genetic disorders.
3. Chemical and Structural Differences
Sugar: DNA contains deoxyribose sugar, whereas RNA contains ribose sugar.
Bases: DNA contains thymine (T), whereas RNA contains uracil (U) instead of thymine.
Strands: DNA is usually double-stranded, whereas RNA is usually single-stranded.
Base Pairing: DNA has A–T and G–C pairing, whereas RNA has A–U and G–C pairing.
Length: DNA molecules are generally longer than RNA molecules.
Stability: DNA is chemically more stable, whereas RNA is comparatively less stable.
Location: DNA is mainly present in the nucleus (in eukaryotic cells), whereas RNA is found in both the nucleus and cytoplasm.
4. Functional Differences
DNA: Stores hereditary information and transfers it to daughter cells and the next generation.
RNA: Uses genetic information to help synthesize proteins.
DNA: Acts as the permanent genetic blueprint of the cell.
RNA: Acts as an intermediary and performs several functions in gene expression and protein synthesis.
Q5. How you can justify that deficiency of different types of vitamins causes diseases in human beings?
Answer
A balanced diet is extremely important for the good health of a person. Insufficient intake of a particular vitamin can lead to a deficiency disease in human beings.List of Deficiency Diseases
Following is a list of major deficiency diseases that occur due to lack of essential minerals and vitamins:
▶ Deficiency of vitamin-A (Retinol) causes Night blindness
▶ Deficiency of vitamin-C (Ascorbic acid) causes Scurvy
▶ Deficiency of vitamin-D (Calciferol) causes Rickets
▶ Deficiency of vitamin-K (Phylloquinone) causes Excessive bleeding due to injury
▶ Deficiency of vitamin-E causes Sterility, haemolysis
▶ Deficiency of vitamin-B1 (Thiamine) causes Beri-beri
▶ Deficiency of vitamin-B2 (Riboflavin) causes Retarded growth, bad skin
▶ Deficiency of vitamin-B12 (Cyanocobalamin) causes Anaemia
Extra Questions
🧬 Biochemistry Chapter #4 – MCQs by Inamjazbi Learn Chemistry 🌟
1️⃣ Glucose is:
🟨 A Vitamin
🟩 B Protein
🟦 C Carbohydrate
🟪 D Lipid
2️⃣ The deficiency of vitamin D causes:
🟨 A Beriberi
🟩 B Rickets
🟦 C Scurvy
🟪 D Haemorrhage
3️⃣ ……… encodes genetic information:
🟨 A R.N.A
🟩 B D.N.A
🟦 C Progesterone
🟪 D Cholesterol
4️⃣ The carbohydrates which contain aldehyde group are called:
🟨 A Saccharides
🟩 B Ketoses
🟦 C Pentose
🟪 D Aldoses
5️⃣ Amino acids are building blocks of:
🟨 A Nucleic acids
🟩 B Protein
🟦 C Vitamins
🟪 D Lipid
6️⃣ Which one of the following is a polysaccharide?
🟨 A Fructose
🟩 B Maltose
🟦 C Starch
🟪 D None
7️⃣ Lactose is:
🟨 A Grape sugar
🟩 B Honey sugar
🟦 C Milk sugar
🟪 D Cane sugar
8️⃣ Cotton contains …. cellulose:
🟨 A 30%
🟩 B 65%
🟦 C 85%
🟪 D 95%
9️⃣ What is true about a peptide?
🟨 A It is a protein
🟩 B It is an anhydride of carboxylic acids
🟦 C It is an anhydride of an amine
🟪 D It is a polyamide
🔟 Fats are solids at:
🟨 A Ordinary room temperature
🟩 B High temperature
🟦 C Higher than 50°C
🟪 D None of them
1️⃣1️⃣ Generally carbohydrates contain H and O in the ratio of:
🟨 A 1:2
🟩 B 3:1
🟦 C 4:1
🟪 D 2:1
1️⃣2️⃣ Hydrolysis of proteins gives:
🟨 A Fatty acids
🟩 B Glycerol
🟦 C Glucose
🟪 D Amino acids
1️⃣3️⃣ Fats and oils (triglycerides) are the esters of fatty acids and:
🟨 A Glycol
🟩 B Ethanol
🟦 C Phenol
🟪 D Glycerol
1️⃣4️⃣ Glucose is:
🟨 A Vitamin
🟩 B Carbohydrate
🟦 C Lipid
🟪 D Protein
1️⃣5️⃣ The deficiency of vitamin D causes:
🟨 A Scurvy
🟩 B Beriberi
🟦 C Rickets
🟪 D Haemorrhage
1️⃣6️⃣ The monosaccharides having aldehydic group are called:
🟨 A Aldoses
🟩 B Trioses
🟦 C Ketoses
🟪 D Pentoses
1️⃣7️⃣ Unsaturated vegetable oils, such as cotton seed oil, are converted into fat on:
🟨 A Hydrogenation
🟩 B Dehydration
🟦 C Oxidation
🟪 D Sulphonation
1️⃣8️⃣ Fatty acids have _______ number of carbon atoms in their chain:
🟨 A Even
🟩 B Whole
🟦 C Odd
🟪 D Fractional
1️⃣9️⃣ ……… encodes a genetic information:
🟨 A D.N.A
🟩 B R.N.A
🟦 C Progesterone
🟪 D Cholesterol
2️⃣0️⃣ The carbohydrates which contain ketonic group are called:
🟨 A Ketoses
🟩 B Saccharides
🟦 C Pentose
🟪 D Aldoses
2️⃣1️⃣ Amino acids are building blocks of:
🟨 A Protein
🟩 B Nucleic acids
🟦 C Vitamins
🟪 D Lipid
2️⃣2️⃣ Which one of the following is a polysaccharide?
🟨 A Starch
🟩 B Maltose
🟦 C Fructose
🟪 D None
2️⃣3️⃣ Lactose is:
🟨 A Grape sugar
🟩 B Honey sugar
🟦 C Milk sugar
🟪 D Cane sugar
2️⃣4️⃣ Cotton contains …. cellulose:
🟨 A 30%
🟩 B 65%
🟦 C 95%
🟪 D 85%
2️⃣5️⃣ Which of the following vitamin’s deficiency lowers the body resistance to infection?
🟨 A Vitamin A
🟩 B Vitamin K
🟦 C Vitamin C
🟪 D Vitamin D
2️⃣6️⃣ Cellulose cannot be hydrolyzed by human body due to lack of enzyme called:
🟨 A Sucrase
🟩 B Lipase
🟦 C Cellulase
🟪 D Amylase
✅ Answers:
0️⃣1️⃣ 🟩 C Carbohydrate
0️⃣2️⃣ 🟦 B Rickets
0️⃣3️⃣ 🟨 B D.N.A
0️⃣4️⃣ 🟨 D Aldoses
0️⃣5️⃣ 🟩 B Protein
0️⃣6️⃣ 🟨 C Starch
0️⃣7️⃣ 🟦 C Milk sugar
0️⃣8️⃣ 🟪 D 95%
0️⃣9️⃣ 🟨 D Polyamide
1️⃣0️⃣ 🟩 A Ordinary room temperature
1️⃣1️⃣ 🟪 D 2:1
1️⃣2️⃣ 🟪 D Amino acids
1️⃣3️⃣ 🟪 D Glycerol
1️⃣4️⃣ 🟩 B Carbohydrate
1️⃣5️⃣ 🟦 C Rickets
1️⃣6️⃣ 🟨 A Aldoses
1️⃣7️⃣ 🟨 A Hydrogenation
1️⃣8️⃣ 🟨 A Even
1️⃣9️⃣ 🟨 A D.N.A
2️⃣0️⃣ 🟨 A Ketoses
2️⃣1️⃣ 🟨 A Protein
2️⃣2️⃣ 🟨 A Starch
2️⃣3️⃣ 🟦 C Milk sugar
2️⃣4️⃣ 🟦 C 95%
2️⃣5️⃣ 🟦 C Vitamin C
2️⃣6️⃣ 🟦 C Cellulase
🧠 Related Posts:
https://learnchemistrybyinamjazbi.blogspot.com/2025/05/x-chemistry-notes-2025-new-concise-notes.html
🧪 BIOCHEMISTRY INTERACTIVE MCQs
Test Your Knowledge | 26 Multiple Choice Questions
By Dr Inam Ul Haq Jazbi
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