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Chemistry class 10 chapter 25 test yourself pdf free download | Biochemistry
10th Class Chemistry Test 1 Chapter wise PDF
Prepare for the Class 10 Chemistry Chapter 25: Biochemistry examination with our Punjab Board 2027 Model Papers. This test series is designed according to the new syllabus issued by PECTAA Punjab and includes Chapter 25 Biochemistry Class Test 1 and a Full Unit Test with exercises. These chapter-wise chemistry tests help students revise important concepts, practise textbook exercises, assess their preparation, and prepare effectively for the Class 10 annual board examinations. Use these free study resources to strengthen your understanding of Biochemistry and improve your exam performance.
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TIME: 10 MINTOTAL MARKS:30MARKS: 8
1.Main classes of food
(a) 2(b)3(c)4(d)5
2.Daily intake fat for an adult is
(a)40-44 g(b)44-56 g(c)44-66 g(d)44-78 g
3.Carbohydrates contain major elements
(a) 2(b) 3(c) 4(d) 5
4.Hormones and enzyme are in nature
(a) protein(b) carbohydrates(c) fats(d) vitamins
5.Fatty acids are long chain of :
(a) Carboxylic acid(b) Alcohol(c) Aldehyde(d) Ketones
6.Fats are chemically known as
(a) Monoester(b) Polyester(c) Diester(d) Trimester
7.Length of DNA molecule is
(a) 10 cm(b) 11 cm(c) 12 cm(d) 14 cm
8.Pregnancy can be detected by testing
(a) Saliva(b) Urine on blood(c) Sweat(d) Mucous
TIME: 22 MINMARKS: 22
Attempt any 7 Questions.7×2=14
iDefine biochemistry
Ans: Biochemistry is the branch of chemistry that deals with the chemical composition of living organisms and the chemical reactions that take place in them.
ii.What is nutrient? Give an example.
Ans: A nutrient is a substance present in food that the body needs for energy, growth, repair and proper working. Example: carbohydrates (glucose), proteins, fats, vitamins, minerals.
iii.Write the application and daily requirement of proteins.
Ans: Applications: growth and repair of body tissues, formation of enzymes and hormones, and body defence (antibodies). Daily requirement: about 0.8 g per kg of body weight for an adult.
iv.Write some basics of healthy diets.
Ans:
- Eat a balanced diet containing all the classes of food.
- Take plenty of fruits, vegetables and enough water.
- Limit sugar, salt and fat.
- Eat suitable portions at regular times.
v.What are carbohydrates?
Ans: Carbohydrates are organic compounds made of carbon, hydrogen and oxygen, with the general formula Cx(H2O)y. They are polyhydroxy aldehydes or ketones, e.g. glucose, sucrose and starch, and are the main source of energy.
vi.What is amino acid? Give example.
Ans: An amino acid is an organic compound that contains both an amino group (–NH2) and a carboxyl group (–COOH). It is the building unit of proteins. Example: glycine, NH2–CH2–COOH.
vii.What is fatty acids?
Ans: Fatty acids are long-chain carboxylic acids present in fats and oils, e.g. palmitic acid and oleic acid.
viii.How can our body have obtained vitamin D?
Ans: Our skin makes vitamin D when exposed to sunlight. It is also obtained from food such as fish liver oil, eggs, milk and butter.
ix.Write the function of DNA.
Ans: DNA stores the genetic information of a living organism, passes it to the next generation by replication, and controls the making of proteins in the cell.
x.What is genetic engineering?
Ans: Genetic engineering is the technique of changing the genes (DNA) of an organism, or moving a gene from one organism to another, to get desired characteristics or products, e.g. making human insulin in bacteria.
SECTION-II
1:What are the sources of fructose, maltose and lactose?(Ex. D.25.1)
Ans:
- Fructose: fruits and honey.
- Maltose: germinated (malted) grains such as barley and wheat.
- Lactose: milk and milk products.
2:Construct peptide linkage and explain the structure of a polypeptide.
Ans: A peptide linkage (–CO–NH–) is formed when the –COOH group of one amino acid reacts with the –NH2 group of another amino acid, and a molecule of water is lost.
NH2CH2COOH + NH2CH2COOH → NH2CH2CO–NHCH2COOH + H2O
Structure of a polypeptide: many amino acids joined by peptide bonds form a long chain called a polypeptide.
- Primary: the order (sequence) of amino acids in the chain.
- Secondary: the chain coils into an α-helix or folds into a β-pleated sheet by hydrogen bonds.
- Tertiary: the coiled chain folds into a definite three-dimensional shape.
