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🔬🌈 Biochemistry (Chapter # 4) MasterClass for X Students | Model Test Questions 2026 | High-Score Booster Guide
🔥📘 Short Questions
🧪⚡Answers of Chemistry Model Questions Test # 1 X Chapter # 4 Biochemistry
🌟💥 Short Questions
Q1. Write
chemical names & deficiency disease arises due to of following Vitamins:
Answer
Q2. Define the following terms:
Peptide linkage, saponification, lipids, biochemistry, enzymes, fats and oils, Proteins, amino acids.
Answer
Peptide linkage
A peptide linkage is an acid-amide bond formed between amino acids by the elimination of water. Due to this linkage protein is formed.
saponification
The alkaline hydrolysis of fats or oils with alkali like NaOH or KOH to give salt of fatty acid called soap and glycerine is called saponification.
lipids
Lipids are a group of naturally occurring heterogeneous organic compounds which includes fats, oils, waxes, and are insoluble in water but easily soluble in Bloor’s reagent (mixture of diethyl ether and ethyl alcohol in the ratio of 2:1) and organic solvents like ether, benzene, acetone, carbon tetrachloride and chloroform.
biochemistry
The branch of chemistry which deals with the study of chemical substances and processes that occur in living organisms (plants and animals) is known as biochemistry.
enzymes
Enzymes are the class of proteins which are the complex polymeric nitrogenous organic biocatalysts produced by living cells that catalyze all types of biochemical reactions in the living organisms.
fats and oils
Oils and fats are triesters of long chain carboxylic (fatty) acids with glycerol. These esters are made of three fatty acids, therefore, they are called triglycerides or triesters. General formula of triglycerides is as under.
Proteins
Proteins are highly complicated macromolecular nitrogenous organic compounds made up of amino acids found in all the cells of living organisms. Proteins are polymers or macro-molecules of simple units called monomers of amino acids which are linked with each other through peptide Linkage. All proteins yield amino acids upon hydrolysis
amino acids.
Amino acids are building blocks of protein. They are bi-functional organic compound containing an acidic carboxyl (–COOH) and a basic amino (–NH2) groups.
Q3. Differentiate
between
Answer
Dextrorotary and Levorotatory Sugars
(ii) fats and oils.
(iii) fat and water soluble vitamins
Q4. Enumerate
the important uses of carbohydrates.
Answer
Uses of Carbohydrates
Q5. How
do plants synthesize carbohydrates? Give equation of preparation.
Answer
Synthesis
of Carbohydrates (glucose) by Plants through Photosynthesis
Carbohydrate like glucose is synthesized by plants through photosynthesis process from carbon dioxide and water in the presence of sunlight and green pigment chlorophyll (catalyst). The glucose is further polymerized to form starch and cellulose.
Q6. What
are Oligosaccharides and Disaccharides. Give their examples and sources.
Answer
Definition
of Oligosaccharides (Greek; Oligo = few)
Oligosaccharides give 2 to 10 (9) units of monosaccharides on hydrolysis. In oligosaccharides, monosaccharides are linked with each other by glycosidic bond or linkage.
Disaccharides
Disaccharides are those oligosaccharides which contain two monosaccharides. The most important oligosaccharides are disaccharides like sucrose. On hydrolysis, sucrose produces one unit of glucose and one unit of fructose.
Examples
Sucrose, maltose, lactose (milk sugar) are important members of disaccharides.
Sources
Sucrose; Sugarcane,
sugar beet, beet root, carrots, maple, pineapple etc.
Lactose; Milk
Maltose ; Wheat(گندم) , barley (جو) etc.
Raffinose; Legumes (phaliyanپھلیاں ،)
Q7. What
are polysaccharides? Give their examples. How monosaccharides are produced from
polysaccharides?
Answer
Polysaccharides are macromolecular carbohydrates also called polymeric carbohydrates giving more than 10 monosaccharides on hydrolysis consisting of hundreds to thousands of monosaccharides linked by glycosidic linkage.
Examples
of polysaccharides
1.cellulose, starch (plant origin), glycogen (animal origin), amylose etc. are common polysaccharides.
Cellulose is found in the cell walls, wood, linen, paper, cotton etc. Cotton contains 95% cellulose.
2. Starch occurs in cereals like wheat, rice, barley etc. and roots of potatoes.
3. Glycogen is also called animal starch found in muscles and liver of animals
Q8. What
are proteins? Give their importance and sources.
Answer
Definition
of Proteins
The word protein is taken from Greek ‘Proteios’ means ‘first’. Proteins are highly complicated macromolecular nitrogenous organic compounds made up of amino acids found in all the cells of living organisms. Proteins are polymers or macro-molecules of simple units called monomers of amino acids which are linked with each other through peptide Linkage. All proteins yield amino acids upon hydrolysis
Function
They have central position in architecture and functioning of living matter.
Sources
and Uses of Proteins
Proteins make up more than 50% of the dry weight of animals. Each protein has its source and carries out a specific function. The important sources of proteins are eggs, pulses, nuts, edible seeds, beans, peas, chees etc. Sources and uses of protein are as follows:
Q9. What
is peptide bond? How it is formed? Also explain dipeptides and tripeptides.
Answer
A peptide linkage is an acid-amide bond formed between amino acids by the elimination of water. Due to this linkage protein is formed. When thousands of amino acids polymerize they form protein. A protein molecule formed with two amino acids is termed as dipeptide, with three tripeptide and so on.
Q10. What are amino acids and give their general structure? How
many Essential and Non-essential Amino acids
are there?
Answer
Amino acids are building blocks of protein. They are bi-functional organic compound containing an acidic carboxyl (–COOH) and a basic amino (–NH2) groups.
Where ‘R’ is Side chain which is different for different amino acids.
Essential
and Non-essential Amino acids
Up to 20 amino acids have been found in nature, ten are essential and remaining ten are non-essential. Body can only synthesize non-essential ten amino acids.
Q11. What
are fatty acids? Give their examples and chemical nature.
Answer
Definition
of Fatty acids
Fatty acids are building blocks of lipids. They are long chain saturated or unsaturated carboxylic acids with a lengthy chain, either saturated or unsaturated. Fatty acids form esters (oils or fats) and glycerol in the presence of mineral acids.
Examples
of Fatty acids
1. Palmitic
acid; C15H31COOH
2. Stearic acid; C17H35COOH
Chemical
Nature
Lipids are macromolecules made up of fatty acids. Lipids include oils and fats. Oils and fats are triesters of long chain carboxylic (fatty) acids with glycerol. These esters are made of three fatty acids, therefore, they are called triglycerides or triesters. General formula of triglycerides is as under.
Q12. Explain
Hydrogenation of vegetable oil into vegetable ghee.
Answer
Hydrogenation
of vegetable oil
Vegetable oils are triester of glycerol and fatty acids of unsaturated long chains. Vegetable oil is converted into saturated fat ghee by the chemical process called hydrogenation. In this process unsaturated vegetable oil is treated with molecular hydrogen (H2) in the presence of catalyst like nickel (ni) or palladium (Pd) at 250-300°C to form vegetable ghee (fat). This is an addition reaction of oil with H2 to form an adduct called fat.
Q13. What
is vitamin D? Give its sources and importance.
Answer
Definition
Vitamin
D(Anthracitic vitamin) is a fat-soluble vitamin.
Sources.
Fish
liver, dairy products (milk, butter), mushrooms, oils and fats, Vitamin D is
formed in the skin when it is exposed to sunlight
Importance
Bones, teeth (controls the metabolism of calcium and phosphorus in body. Its deficiency leads to Rickets (softening and weakening of bones in children).
Q14. What
are nucleic acids? Write down importance of deoxyribonucleic acid (DNA).
Answer
Nucleic acids are biopolymers which are the macromolecules formed by the polymerization of nucleotides (monomers). They contain elements like carbon, hydrogen, oxygen, nitrogen and rarely phosphorus. They are generally long chain molecules made up of nucleotides. Each nucleotide consists of three components; nitrogenous base (purines and pyrimidines), a pentose sugar and a phosphate group).
Importance
of Nucleic Acid
1. They are the most vital material for
cell functioning.
2. They are the storage of genetic
information.
3. They work for mutation to save the
cells and body form threatening diseases.
4. They transfer heredity characters
from one generation to another generation.
5. They serve as a source of energy in the form of ATP.
Q15. Write
down the range of Number of Amino acids
and molecular weights of Proteins
Answer
Number of Amino acids in Proteins=60 to 6000 amino acids
molecule weight of proteins= 43000-50,000,000 daltons (1 dalton = 1amu).
Q17. Describe the sources and uses of vitamin
A.
Answer
Sources
Butter, fish, eggs, milk, cheese
(Dairy products) etc. It can also be obtained from the beta-carotene found in
green and yellow vegetables, carrots and liver.
Uses
Important for Eyes (form visual pigments) and skin. Its deficiency causes Night blindness (inability to see in dim light), Xerophthalima (tear glands cease to function), dryness of skin etc. eye inflammation
Q18. Justify that water soluble vitamins are
not injurious to health.
Answer
Water-soluble
vitamins are rapidly excreted from the body. Hence, these vitamins are not
toxic even if taken in large quantity. However, their deficiency causes
disease.
🌟💥 Detailed Questions🧪📚
Q1. What
are the carbohydrates? Explain sources and types of carbohydrates.
Answer
Definition
Carbohydrates are naturally occurring organic compound are important food factor. Carbohydrates are macromolecules defined as polyhydroxy aldehydes or polyhydroxy ketones or large molecules that give these compounds on hydrolysis. They generally contain elements like carbon, hydrogen and oxygen.
General
formula
They have general formula Cn(H2O)n showing that these compound contain hydrogen and oxygen in the ratio as in H2O i.e. 2:1 (although they do not contain water molecules).
Classification
of carbohydrates based on hydrolysis
Carbohydrates
are classified as into three types based on hydrolysis:
1. Monosaccharides
2. Oligosaccharides
3. Polysaccharides
Monosaccharides
(Greek; Mono = one)
Definition
Monosaccharides are the simplest sugars which cannot be further simplified on hydrolysis.
No of
Carbon atoms
They consist of 3 to 10 (9) carbon atoms.
Properties
Monosaccharides are white crystalline solids. They are soluble in water and have sweet taste. They cannot be hydrolyzed. They are reducing in nature, therefore, these are called reducing sugars.
Types
they are further classified according to the number of carbon atoms in their molecules as trioses, tetroses, pentoses, hexoses, and so on.
The important monosaccharides are hexoses like glucose and fructose, etc.
Glucose
1. Glucose (grape sugar) belongs to aldoses and fructose (honey) to ketones are examples of monosaccharides.
2. Glucose is obtained naturally as dextrorotatory and is present in grapes (20-30%), honey. It is also found in combined state in cane sugar, starch and cellulose.
3. Glucose is a rapid source of energy for patients. Fructose (Latin; fructus = fruit) occurs in ripe fruits, honey, cane sugar etc.
4. Glucose is a necessary component of human blood, that is why it is also known as blood sugar. The normal range for blood glucose is 65-110 mg (0.06-0.1%) per 100 mL.
Glucose is a pentahydroxy aldehyde (aldo hexose) while fructose is pentahydroxy ketone (keto hexose) having the open chain structures as follows and general formula C6H12O6
Oligosaccharides
(Greek; Oligo = few)
Definition
Oligosaccharides give 2 to 10 (9) units of monosaccharides on hydrolysis. In oligosaccharides, monosaccharides are linked with each other by glycosidic bond or linkage.
Properties
Oligosaccharides like monosaccharides are white, crystalline solids, sweet in taste and easily soluble in water. (They may be reducing or non-reducing).
Types
they are classified as disaccharides, trisaccharides, tetrasaccharides etc., depending upon the number of monosaccharides units they produce on hydrolysis.
Disaccharides
Disaccharides are those oligosaccharides which contain two monosaccharides. The most important oligosaccharides are disaccharides like sucrose. On hydrolysis, sucrose produces one unit of glucose and one unit of fructose.
Examples
Sucrose, maltose, lactose (milk sugar) are important members of disaccharides.
Polysaccharides
Definition
Polysaccharides are macromolecular carbohydrates also called polymeric carbohydrates giving more than 10 monosaccharides on hydrolysis consisting of hundreds to thousands of monosaccharides linked by glycosidic linkage.
Properties
Polysaccharides are amorphous, tasteless and insoluble in water. They are non-reducing in nature.
Examples
of polysaccharides
1. cellulose, starch (plant origin), glycogen (animal origin), amylose etc. are common polysaccharides.
Cellulose
is found in the cell walls, wood, linen, paper, cotton etc. Cotton contains 95%
cellulose.
2. Starch occurs in cereals like wheat,
rice, barley etc. and roots of potatoes.
3. Glycogen is also called animal starch found in muscles and liver of animals
Q2. What
are lipids? Write down the sources and uses of lipids.
Answer
Definition
Lipids are a group of naturally occurring heterogeneous organic compounds which includes fats, oils, waxes, and are insoluble in water but easily soluble in Bloor’s reagent (mixture of diethyl ether and ethyl alcohol in the ratio of 2:1) and organic solvents like ether, benzene, acetone, carbon tetrachloride and chloroform.
Constituent
Elements
Lipids are generally composed of elements like carbon, hydrogen and oxygen but there are some lipids which contain nitrogen and phosphorus too. Lipids are the building blocks of cells.
Sources
of Lipids
Animals
Marine animals like salmon and whales are rich sources of lipids. Butter, ghee, cheese are obtained from animals.
Plants
Sun flower, coconut, ground nuts, corn, cotton seed, olive etc. are important plant sources of lipids.
Uses
of Lipids
1. They act as transporter of fatty
acids and fat soluble vitamins (A, D, E and K) in body.
2. Some lipids reduce cholesterol level
in body.
3. Fats and oils are used for cooking
and frying of food.
4. Fats and oils are used in
detergents, soaps, cosmetic, polishes and paints.
5. They activate the enzymes.
6. Animals fats are found in adipose tissue cells. Animals secrete milk from which butter and ghee is obtained which are used for cooking and frying of food, for preparing bakery products and sweets.
Q3. Describe
vitamins and types of vitamins.
Answer
In 1912, Hopkins noticed that in addition to carbohydrates, proteins and fats there are other nutrients needed for normal growth. Although these substances were needed in small quantity, yet these substances were called Accessory Growth Factors. Later Funk proposed the name Vitamin for these substances. He discovered Vitamin B1 (Thiamin).
Types
of Vitamins on the Basis of Solubility
Vitamins are divided into two types based on their solubility:
(i)
Water Soluble Vitamins
The
vitamins that dissolve in water are called water-soluble vitamins. They are
obtained from cereals and fruits. These vitamins are not stored in body.
These vitamins are B complex (this include 10 vitamins) and vitamin C (ascorbic acid). Water-soluble vitamins are rapidly excreted from the body. Hence, these vitamins are not toxic even if taken in large quantity. However, their deficiency causes disease.
(ii)
Fat Soluble Vitamins
The
vitamins which dissolve in fats and organic solvents are called fat soluble
vitamins. These are vitamin A, D (sunshine vitamin), E and K. They are stored
in the body for long period of time. These vitamins are obtained from lipids. If these vitamins are taken in large quantity,
they accumulate in the body and cause diseases.
For
example,
(i) Excess of vitamin A causes irritation
and headache
(ii) Vitamin D calcification (accumulation)
in the body causes bone-pain and bonelike deposits in the kidney.
(iii) Vitamin E excess causes fatigue and
headache
(iv) Excess vitamin K causes liver and kidney diseases.
Sources, uses and diseases due to deficiency of some fat soluble vitamins.
Q4. Describe
in detail nucleic acids, RNA and DNA.
Answer
ribonucleic Acid (RNA)
It consists of ribose sugar. It is a single stranded molecule. It is responsible for putting the genetic information to work in the cell to build proteins. Its role is like a messenger.
RNA is synthesized by DNA to transmit the genetic information. RNA receives, reads, decodes and uses the given information to synthesize new proteins. Thus RNA is responsible for directing the synthesis of new proteins.
Deoxyribonucleic Acid (DNA)
DNA consists of deoxyribose sugar. Its structure was discovered by J. Watson and F. Crick in 1953. It is long two-chained double stranded molecule consisting of two chains of considerable length.
Each chain is made up of sugar, phosphate and a base. The sugar and phosphate groups make the backbone of the chains and two chains are linked through bases. The chains are wrapped around each other in a double helix form as shown in figure
DNA is the permanent storage place for genetic information in the nucleus of a cell. It carries and stores all genetic information of the cell. It passes these information as instructions from generation to generation how to synthesize particular proteins from amino acids. These instructions are ‘genetic code of life’. They determine whether an organism is a man or a tree or a donkey and whether a cell is a nerve cell or a muscle cell.
The sequence of nitrogenous bases in DNA determines the protein development in new cells. The function of the double helix formation of DNA is to ensure that no disorder takes place.
DNA carries genes that controls the synthesis of RNA. Errors introduced into the genes synthesize faulty RNA. It synthesizes faulty proteins that do not function the way they are supposed to. This disorder causes genetic diseases.
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
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
1️⃣ 🟩 C Carbohydrate
2️⃣ 🟦 B Rickets
3️⃣ 🟨 B D.N.A
4️⃣ 🟨 D Aldoses
5️⃣ 🟩 B Protein
6️⃣ 🟨 C Starch
7️⃣ 🟦 C Milk sugar
8️⃣ 🟪 D 95%
9️⃣ 🟨 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
🧠
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