Biomolecules MCQS: Introduction & Explanation, Introduction & Explanation

Biomolecules are a diverse group of molecules that are essential for the proper functioning of living organisms. These molecules are made up of various elements such as carbon, hydrogen, oxygen, nitrogen, and phosphorus, and are involved in a wide range of biological processes, including metabolism, DNA replication, and cell signaling. It is an important part of Biology basics and connects some of the major chapters like cell, and Molecular basis of Inheritance.

To help readers test their knowledge of biomolecules, MCQs (Multiple Choice Questions) can be a useful tool. MCQs are questions that present several possible answers, with only one correct answer.

Q1. What is a biomolecule?

1. A group of molecules.

2. A molecule that is produced by living organisms.

3. A particle of matter that defines a chemical element.

4. A distinct compound substance.

Ans. (a)

• A molecule that is produced by living organisms is called a biomolecule.

• Biomolecules are molecules that are produced by living organisms and are essential for the proper functioning of cells and tissues.

• These molecules include carbohydrates, lipids, proteins, and nucleic acids, which are the building blocks of life.

• Carbohydrates provide energy for cells and are found in foods such as fruits, vegetables, and grains.

• Lipids are essential for cell membrane structure and function and are found in foods such as oils, nuts, and seeds.

• Proteins are involved in a variety of cellular processes, including metabolism, DNA replication, and cell signalling.

• Nucleic acids are involved in the storage and transmission of genetic information, such as DNA and RNA.

• Biomolecules play a crucial role in maintaining the structure and function of cells and tissues, and their proper functioning is essential for overall health and well-being.

Q2. Large macromolecules of biomolecules include

1. Proteins

2. Carbohydrates

3. Both a & b

4. None of the above

Ans. (c)

• Macromolecules are large molecules made up of smaller subunits called monomers, which are repeated to form a chain-like structure.

• Proteins and carbohydrates are both examples of macromolecules in biomolecules.

• Proteins are made up of amino acid monomers that are joined together through peptide bonds to form long chains.

• Proteins have a wide range of functions in the body, including structural support, enzymatic activity, and transportation of molecules.

• Carbohydrates are made up of monosaccharide monomers that are joined together through glycosidic bonds to form polysaccharide chains.

• Carbohydrates are a major source of energy for the body and also play important roles in cell signalling and communication.

• Other examples of macromolecules in biomolecules include nucleic acids, such as DNA and RNA, which are made up of nucleotide monomers joined together through phosphodiester bonds, and lipids, such as fats and oils, which are made up of glycerol and fatty acid monomers.

• Overall, macromolecules are essential components of biomolecules and play a crucial role in maintaining the structure and function of cells and tissues.

Q3. Glycogen is a polymer of

1. Galactose

2. Glucose

3. Protein

4. Fructose

Ans. (b)

• Glycogen is a complex carbohydrate and a polymer of glucose, which means it is made up of many glucose molecules linked together.

• It is the main storage form of glucose in animals and is stored primarily in the liver and muscle tissue.

• When the body needs energy, such as during exercise or periods of fasting, glycogen is broken down into individual glucose molecules through a process called glycogenolysis.

• The glucose is then used by the body as an energy source to fuel cellular processes.

• Glycogen is similar in structure to starch, which is the main storage form of glucose in plants.

• Both glycogen and starch are composed of many glucose molecules joined together by alpha-1,4-glycosidic bonds, and have branched structures formed by alpha-1,6-glycosidic bonds.

• Overall, glycogen plays an important role in maintaining energy homeostasis in the body and is a crucial source of energy during periods of high energy demand.

Q4. Biomolecules are classified into

1. Macromolecules

2. Multimolecules

3. Macromolecules

4. Both a & c

Ans. (d)

• Biomolecules can be classified into two broad categories: micromolecules and macromolecules.

• Micromolecules are small molecules that have a molecular weight of less than 1000 daltons. They include molecules such as amino acids, simple sugars, nucleotides, and fatty acids. These micromolecules are often the building blocks of larger biomolecules and are essential for the proper functioning of cells and tissues.

• Macromolecules, on the other hand, are large molecules that have a molecular weight of more than 1000 daltons. They are composed of many smaller subunits called monomers that are joined together to form a chain-like structure. Examples of macromolecules in biomolecules include proteins, carbohydrates, nucleic acids, and lipids. These macromolecules play crucial roles in maintaining the structure and function of cells and tissues.

Q5. Which of the following is a micromolecule?

1. Lipids

2. Sugars

3. Nucleic acids

4. Carbohydrates

Ans. (b)

• Micromolecules are small molecules that have a molecular weight of less than 1000 daltons. They are often referred to as biomolecules and are the building blocks of larger macromolecules. Micromolecules include molecules such as amino acids, simple sugars, nucleotides, and fatty acids.

• Out of the options given, sugars are macromolecules. Simple sugars, also known as monosaccharides, are the basic building blocks of carbohydrates, which are a type of macromolecule. Examples of monosaccharides include glucose, fructose, and galactose. These molecules are used by cells to produce energy through cellular respiration.

• Lipids are another type of macromolecule that includes molecules such as fats, oils, and waxes. They play important roles in energy storage, insulation, and cell membrane structure.

• Nucleic acids, such as DNA and RNA, are also macromolecules. They play a critical role in storing and transmitting genetic information, as well as in protein synthesis.

• Overall, understanding the difference between micromolecules and macromolecules and the various types of molecules within each category is important for understanding the role that biomolecules play in biological processes.

Q6. Enzymes are commonly known as

1. Biomolecules

2. Cofactors

3. Polysaccharides

4. Biocatalyst

Ans. (d)

• Enzymes are specialized proteins that act as biological catalysts, increasing the rate of chemical reactions in living organisms without being consumed in the process. They are essential for many biological processes, including metabolism, DNA replication, and protein synthesis.

• Enzymes are often referred to as biocatalysts because they accelerate chemical reactions by lowering the activation energy required for the reaction to occur. This allows the reaction to occur more quickly and with less energy input.

• Enzymes are highly specific in their function, meaning that each enzyme catalyzes only one particular chemical reaction. This specificity is due to the unique three-dimensional shape of the enzyme, which allows it to bind to only certain substrates (the molecules upon which the enzyme acts).

Q7. Insulin is made up of

1. Glucose & Fructose

2. Glucose & Glucose

3. Mannose & Fructose

4. Mannose & Fructose

Ans. (d)

• Insulin is a hormone produced by the pancreas that regulates blood sugar levels by promoting the uptake and storage of glucose in cells. It is a protein hormone composed of two peptide chains: an A chain and a B chain, which are linked together by disulfide bonds.

• The A chain of insulin is composed of 21 amino acids, while the B chain is composed of 30 amino acids. These amino acids are arranged in a specific sequence that gives insulin its unique three-dimensional structure.

• The A chain of insulin contains two disulfide bonds, while the B chain contains one disulfide bond and one intramolecular bond. The disulfide bonds help to stabilize the structure of insulin and are critical for its biological activity.

• The composition of insulin does not include glucose or fructose. Mannose is a monosaccharide that is not present in insulin. However, insulin does play a critical role in regulating glucose levels in the body by promoting the uptake of glucose into cells and the conversion of glucose into glycogen for storage in the liver and muscles.

Q8. NADP contains which vitamin?

1. B12

2. B6

3. B3

4. B1

Ans. (c)

• NADP stands for nicotinamide adenine dinucleotide phosphate, which is a coenzyme that plays a crucial role in many biological processes, including photosynthesis, cellular respiration, and biosynthesis of macromolecules. NADP is a derivative of NAD (nicotinamide adenine dinucleotide) and contains an additional phosphate group.

• NADP is synthesized in cells from vitamin B3, also known as niacin or nicotinic acid. Vitamin B3 is an essential nutrient that cannot be synthesized by the body and must be obtained through the diet. It plays a critical role in many metabolic pathways, including the production of energy from food, DNA repair, and the maintenance of healthy skin, nerves, and digestion.

• Vitamin B12, also known as cobalamin, is important for the proper functioning of the nervous system, the formation of red blood cells, and DNA synthesis. Vitamin B6, also known as pyridoxine, is involved in many aspects of protein metabolism, as well as the production of neurotransmitters and the synthesis of haemoglobin. Vitamin B1, also known as thiamine, is important for the metabolism of carbohydrates and branched-chain amino acids, as well as the proper functioning of the nervous system.

Q9. The bond between individual monosaccharides is called

1. Peptide bond

2. Glycosidic Linkage

3. Tertiary bond

4. Phospho-diester bond

Ans. (b)

• Monosaccharides are simple sugars that can be linked together by a covalent bond called a glycosidic linkage to form larger carbohydrates. A glycosidic linkage is formed when a hydroxyl (-OH) group on one monosaccharide molecule reacts with the anomeric carbon atom of another monosaccharide molecule, releasing a molecule of water.

• The type of glycosidic linkage formed between monosaccharides depends on the position of the anomeric carbon atom and the orientation of the hydroxyl group involved in the linkage. For example, if the hydroxyl group on the anomeric carbon of one monosaccharide is oriented in the same direction as the hydroxyl group on the other monosaccharide, an alpha-glycosidic linkage is formed. If the hydroxyl groups are oriented in opposite directions, a beta-glycosidic linkage is formed.

• Peptide bonds are covalent bonds that link amino acids together in proteins. Tertiary bonds refer to interactions between R groups in proteins that contribute to their three-dimensional structure. Phospho-diester bonds are covalent bonds that link nucleotides together in DNA and RNA.

• In summary, the bond between individual monosaccharides is called a glycosidic linkage, which is formed by a covalent bond between a hydroxyl group on one monosaccharide and the anomeric carbon atom of another monosaccharide.

Q10. Chemical equation of Glucose

1. C6H12O6

2. C6H6O6

3. C3H12O6

4. C6H12O3

Ans. (a)

• Glucose is a simple sugar and its chemical formula is C6H12O6. This means that each glucose molecule contains 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Glucose is an important biomolecule that plays a key role in cellular energy metabolism in living organisms. It is produced by plants through the process of photosynthesis and is used as a source of energy by all living cells through the process of cellular respiration.

• C6H6O6 is not the chemical formula for glucose, but rather for another isomer of glucose called fructose. C3H12O6 is not a valid chemical formula, as it implies a molecule with more hydrogen atoms than possible for the given number of carbon and oxygen atoms. C6H12O3 is the chemical formula for a different type of sugar called hexanoic acid.

Q11. Which of the following is an example of a fatty acid

1. Glycine

2. Ribose

3. Arachidonic acid

4. Cyticlyic acid

Ans. (c)

• Fatty acids are a type of organic molecule that consists of a long hydrocarbon chain with a carboxyl group at one end. They are an important component of many lipids, such as triglycerides and phospholipids, which are essential for cellular structure and function.

• Arachidonic acid is a type of polyunsaturated fatty acid that is found in animal fats and is an important precursor for the synthesis of eicosanoids, which are hormone-like signalling molecules that play a role in inflammation, blood clotting, and other physiological processes. Glycine and ribose are not fatty acids, but rather amino acids and sugars, respectively. Cyticlyic acid is not a valid compound name.

Q12. The structure that is not common in all proteins is called

1. Tertiary Structure

2. Secondary Structure

3. Primary Structure

4. Quarternary Structure

Ans. (c)

Proteins are complex biomolecules made up of one or more polypeptide chains that are folded into a specific three-dimensional structure. The structure of a protein determines its function, and the folding of a protein is determined by its amino acid sequence.

The four levels of protein structure are:

• Primary Structure: This refers to the linear sequence of amino acids in a protein chain.

• Secondary Structure: This refers to the local folding of the polypeptide chain into regular structures such as alpha helices and beta sheets.

• Tertiary Structure: This refers to the overall three-dimensional structure of a single polypeptide chain, including the folding of the secondary structures.

• Quaternary Structure: This refers to the arrangement of multiple polypeptide chains into a larger, functional protein complex.

While the primary, secondary, and tertiary structures are common to all proteins, not all proteins have a quaternary structure. Some proteins, such as enzymes, are composed of a single polypeptide chain and do not have a quaternary structure, while others, such as haemoglobin, are composed of multiple polypeptide chains and do have a quaternary structure.

Q13. Name the protein which forms the intercellular ground substance

1. Collagen

2. Egg

3. Fibrous

4. Keratin

Ans. (a)

• Fibrous proteins are a class of proteins that are characterized by their elongated, thread-like shape and their structural functions. They are commonly found in connective tissues, such as tendons, ligaments, and cartilage, where they provide tensile strength and support.

• One of the main functions of fibrous proteins is to form the extracellular matrix, which is the non-cellular component of tissues that provides structural support and helps to maintain the integrity of tissues. The extracellular matrix is composed of a complex mixture of proteins, including fibrous proteins such as collagen and elastin.

• Collagen is a type of fibrous protein that is particularly important in connective tissues, where it provides strength and support. However, it is not the protein that forms the intercellular ground substance. Instead, the intercellular ground substance is composed of a gel-like mixture of polysaccharides, glycoproteins, and proteoglycans that fills the spaces between cells and helps to maintain tissue structure.

• Therefore, the correct answer is fibrous protein, as fibrous proteins play a key role in the formation of the extracellular matrix and the maintenance of tissue structure.