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Class 10 Chemistry Chapter 25 Biochemistry Class Test 8 PDF Free Download | Punjab Board 2027
Prepare for your Class 10 Chemistry Chapter 25: Biochemistry Class Test 8 with the latest Punjab Board 2027 Model Papers. This chapter-wise test is designed according to the new syllabus issued by PECTAA Punjab and is useful for students preparing for their Class 10 Chemistry examinations. Download and practice the Chapter 25 Biochemistry test, Full Unit Model Paper, and Chapter Wise Test Series to strengthen your concepts, revise important topics, and improve your exam preparation.
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Full Chapter Test
Test No. 8
CHAPTER # 25
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Note:
Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with Marker or Pen ink. Cutting or filling two or more circles will result in zero mark in that question.
1.A special types of animal fat obtained from milk is called:
(a) oil(b) wax(c) ghee(d) butter
2.An adult consume proteins per day is:
(a) 40g(b) 50g(c) 60g(d) 70g
3.Carbohydrates contain functional group.
(a) aldehyde(b) carboxylic(c) ketone(d) aldehyde or ketone
4.Deficiency of vitamin A cause:
(a) rickets(b) dry skin(c) hollow bone(d) scurvy
5.Molecular mass of polymers measure in unit:
(a) Da(b) DA(c) NA(d) De
6.Genetic testing mainly studies:
(a) proteins(b) enzymes(c) hormones(d) genes
7.Functional groups present in fructose are:
(a) Hydroxyl and aldehyde(b) Hydroxyl and Ketone(c) Hydroxyl and ester(d) Hydroxyl and amide
8.Which functional group is present in a fat?
(a) Carboxyl group(b) Ester group(c) Carbonyl group(d) Hydroxyl group
9.Which functional groups react to produce a peptide linkage in proteins?
(a) Carboxyl group and hydroxyl group(b) Carboxyl group and amino group(c) Hydroxyl group and amino group(d) Ester group and amino group
10.Fatigue and depression are caused by deficiency of:
(a) Vitamin A(b) Vitamin C(c) Vitamin D(d) Vitamin B1
11.Vitamin C is also called:
(a) oleic acid(b) lauric acid(c) ascorbic acid(d) scurvy
12.Main function of DNA is:
(a) make protein(b) store genetic information(c) make fat(d) make vitamin
Here is Subjective Part of Paper.
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Marks: 48
CHEMISTRY (SUBJECTIVE TYPE)
Time: 1:45 minute
Part – I
2.Write short answers to any Five (5) questions:[5×2=10]
- (i)Where protein are found?In animal sources: meat, fish, eggs, milk and cheese; in plant sources: pulses (lentils, beans), nuts and soybeans. In the body: muscles, skin, hair, nails and blood.
- (ii)How much carbohydrates are required per day?About 45–65% of daily calories, roughly 300 g per day for an average adult (check your textbook value).
- (iii)Write some Basics of Healthy eating.
- Eat a balanced diet with a variety of foods
- Eat more fruits, vegetables and whole grains
- Reduce saturated fats, sugar and salt
- Avoid processed and fast food; drink plenty of water
- Eat regular meals in proper portions
- (iv)Write the structural formula of fructose.Fructose, C6H12O6 (a ketohexose): CH2OH–CO–CHOH–CHOH–CHOH–CH2OH
D-Fructose (open chain)
- (v)Write the role of insulin and enzymes in the body?Insulin: a protein hormone that controls blood sugar by helping cells take up glucose. Enzymes: protein catalysts that speed up biochemical reactions such as digestion.
- (vi)How peptide linkage is formed?The –COOH group of one amino acid reacts with the –NH2 group of another amino acid, and a molecule of water is lost (condensation), forming the peptide bond –CO–NH–.
- (vii)Why do children need a large amount of protein?Because children grow rapidly; proteins are needed to build new cells, muscles, bones, enzymes and hormones.
- (viii)Where are animal fats and vegetable oils found?Animal fats: in adipose tissue under the skin, milk, meat, eggs and fish. Vegetable oils: in seeds and fruits such as sunflower, mustard, corn, olive, coconut and palm.
3.Write short answers to any Five (5) questions:[5×2=10]
- (i)Write the deficiency symptoms of vitamin B1 and B2?Vitamin B1 (thiamine): beri-beri, loss of appetite, fatigue, depression, weak muscles and nerve damage.
Vitamin B2 (riboflavin): cracks at the corners of the mouth, sore tongue, skin inflammation and eye problems. - (ii)What is the purpose of pregnancy test and how can measure?The test confirms pregnancy. It is measured by detecting the hormone hCG (human chorionic gonadotropin) in urine (test strip) or in blood (laboratory test).
- (iii)What is cloning? Write its importance.Cloning is making genetically identical copies of a gene, cell or organism. Importance: producing useful genes and proteins (e.g. insulin), medical research, growing tissues and organs, and saving endangered species.
- (iv)Which two function are performed by proteins?1) They act as enzymes (catalysts) in the body. 2) They carry oxygen in blood (hemoglobin). (Also growth and repair.)
- (v)What is balanced diet?A diet that contains all nutrients (carbohydrates, proteins, fats, vitamins, minerals, fibre and water) in the right proportions to meet the needs of the body.
- (vi)Are all carbohydrates equally beneficial for our health?No. Complex carbohydrates with fibre (whole grains, vegetables, fruits) are beneficial; refined sugars and processed starches give quick energy but can cause obesity and diabetes.
- (vii)What is denaturation of proteins?The loss of the natural three-dimensional shape (and function) of a protein caused by heat, acids, alkalis, heavy metals, or oxidizing / reducing agents. Example: boiling an egg.
- (viii)Which is an unsaturated fatty acid?Oleic acid, C17H33COOH, i.e. CH3(CH2)7CH=CH(CH2)7COOH (one C=C double bond). Linoleic acid is another example.
4.Write short answers to any Five (5) questions:[5×2=10]
- (i)Compare the roles played by Vitamins and Carbohydrates in our body?
Vitamins Carbohydrates Needed in very small amounts Needed in large amounts Do not give energy Main source of energy Regulate body processes, help enzymes, prevent deficiency diseases Fuel for body; stored as glycogen; fibre aids digestion - (ii)What is the difference between glucose and fructose?Glucose is an aldohexose (aldehyde group, –CHO); fructose is a ketohexose (ketone group, >C=O). Both are C6H12O6; fructose is sweeter.
- (iii)What are the sources of vitamin D?Sunlight, fish liver oil, egg yolk, milk, butter and fortified foods.
- (iv)Which commercial products are obtained from oils and fats?Soaps, detergents, candles, margarine (vegetable ghee), glycerol, paints, cosmetics and biodiesel.
- (v)What is the function of DNA?DNA stores genetic information, passes it from parents to offspring and directs protein synthesis.
- (vi)Write down three important functions played by of proteins in our body.1) Growth and repair of tissues. 2) Enzymes (catalysts). 3) Transport of oxygen (hemoglobin); also hormones and antibodies.
- (vii)Fatty acids serve as building blocks of lipids just like amino acids are for proteins. Comment on this statement.Partly true. Fatty acids join with glycerol (ester linkage) to form fats and oils, as amino acids join by peptide bonds to form proteins. But lipids are not true polymers: fatty acids do not link in a long repeating chain like amino acids.
- (viii)Write down about the sources of vitamin D. Which diseases are caused by its deficiency?Sources: sunlight, fish liver oil, egg yolk, milk and fortified foods. Deficiency causes rickets in children and osteomalacia in adults.
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A polypeptide is a long, unbranched chain of amino acids (R = side chain) joined by peptide bonds (–CO–NH–), with a free –NH2 end and a free –COOH end. Its structure has four levels:
Nucleic acids are large biomolecules (polymers) made of nucleotides; each nucleotide has a phosphate group, a five-carbon sugar and a nitrogen base. They are of two types:
Part – II
NOTE:- Attempt any two questions.[9×2=18]
5.(a)What is Nutrition. Write its Importance.
Nutrition: the process by which the body takes in food and uses its nutrients for energy, growth and repair.
Importance: supplies energy; builds and repairs tissues; keeps the immune system strong; prevents deficiency diseases and obesity; supports mental and physical development.
Importance: supplies energy; builds and repairs tissues; keeps the immune system strong; prevents deficiency diseases and obesity; supports mental and physical development.
(b)Explain the structure of Poly peptide.
Polypeptide chain (amino acids joined by peptide bonds)
- Primary: sequence of amino acids.
- Secondary: α-helix or β-pleated sheet held by hydrogen bonds.
- Tertiary: overall 3-D folding of one chain.
- Quaternary: several chains joined together (e.g. hemoglobin).
6.(a)Write note on denaturation of protein.
Definition: the loss of the natural 3-D structure of a protein, so it loses its biological activity.
Causes: heat, strong acids or alkalis, heavy metal salts, alcohol, and oxidizing or reducing agents.
Examples: cooking an egg (white turns solid); curdling of milk by acid.
Effect: the peptide chain stays intact, but the folding (secondary, tertiary structure) is destroyed; it is usually irreversible.
Causes: heat, strong acids or alkalis, heavy metal salts, alcohol, and oxidizing or reducing agents.
Examples: cooking an egg (white turns solid); curdling of milk by acid.
Effect: the peptide chain stays intact, but the folding (secondary, tertiary structure) is destroyed; it is usually irreversible.
(b)What are vitamins? Write its importance (Source and Disease due to deficiency of vitamins).
Vitamins: organic compounds needed in small amounts for growth, health and normal body functions; they do not give energy.
| Vitamin | Source | Deficiency disease |
|---|---|---|
| A | Carrots, liver, milk | Night blindness, dry skin |
| B1 | Whole grains, meat, eggs | Beri-beri |
| B2 | Milk, eggs, green vegetables | Cracked lips, sore tongue |
| C | Citrus fruits, guava | Scurvy |
| D | Sunlight, fish oil, eggs | Rickets |
| K | Green vegetables | Delayed blood clotting |
7.(a)Write a note on Nucleic acid.
Nucleotide (unit of nucleic acid)
| DNA | RNA |
|---|---|
| Double-stranded helix; sugar deoxyribose | Single-stranded; sugar ribose |
| Bases: A, T, G, C | Bases: A, U, G, C |
| Stores genetic information | Helps in protein synthesis (mRNA, tRNA, rRNA) |
(b)Write applications of Biochemistry.
Medicine (diagnosis, drugs, vaccines, insulin); genetic testing, gene therapy and cloning; forensic science (DNA fingerprinting); agriculture (fertilizers, improved crops); food and nutrition; industry (soap, fermentation, enzymes, biofuels); and environmental protection.
