Biomolecules MCQ Quiz - Objective Question with Answer for Biomolecules - Download Free PDF

The Correct answer is Vitamins are organic compounds required in small amounts for various bodily functions.

Key Points

• Vitamins are organic compounds, meaning they contain carbon and are derived from living organisms.
• These compounds are required in small amounts but are essential for maintaining normal physiological functions such as growth, immunity, and metabolism.
• Unlike macronutrients like carbohydrates, fats, and proteins, vitamins do not provide energy but facilitate the body's energy production processes.
• Vitamins are divided into fat-soluble (A, D, E, K) and water-soluble (B-complex and C) categories based on their solubility and how the body processes them.
• Since the human body cannot synthesize most vitamins in sufficient quantities, they must be obtained through diet or supplementation.
• Deficiencies in vitamins can lead to health issues like scurvy (Vitamin C deficiency), rickets (Vitamin D deficiency), and beriberi (Vitamin B1 deficiency).
• Sources of vitamins include fruits, vegetables, grains, and animal products, depending on the type of vitamin.

The correct answer is - 3) Protein

Concept:

Fat -

• Fats are a type of lipid consisting of triesters of glycerol and fatty acids or triglycerides. 

Carbohydrates -

• Carbohydrates are defined as “optically active polyhydroxy aldehydes or ketones or the compounds which produce units of such type on hydrolysis”. 

Protein - 

• A protein is a naturally occurring, extremely complex substance that consists of amino acid residues joined by peptide bonds.

Nucleic Acid - 

• Nucleic acids are polynucleotides that are, long chainlike molecules composed of a series of nearly identical building blocks called nucleotides.
• Each nucleotide consists of a nitrogen-containing aromatic base attached to a pentose (five-carbon) sugar, which is in turn attached to a phosphate group

Explanation:

Biuret test - The biuret test is a chemical test that can be used to check for the presence of peptide bonds in a given analyte.

• Therefore, the biuret test can also be used to gauge the amount of protein present in the analyte.
• In this test, the presence of peptides results in the formation of pale purple-coloured coordination compounds of the copper (II) ion (when the solution is sufficiently alkaline). 
• The copper (II) present in the reaction binds itself to the nitrogen atoms that are present in the protein peptides. 

Therefore, the Biuret test is used to test the presence of Protein.

Concept:

• Amino acids are organic compounds containing both amino and carboxylic groups in their molecules.
• They also contain a side chain that varies and is specific to each amino acid.
• While there are over 500 amino acids occurring in nature, only 20 are required by our body..

Acidic, basic, and neutral amino acids.

• Whether an amino acid is basic or neutral depends on the relative number of amino and carboxylic groups in the molecule.
  • When Carboxylic group > amino group, the molecule is acidic.
  • When amino group > carboxylic group, the amino acid is basic.
  • When amino group = acid group, the molecule is neutral.

Explanation:

Amino acids:

• Amino acids are essential for the functioning of a healthy body.
• The human body can synthesize 10 out of 20 amino acids. They are called non-essential amino acids.
• To make up for the deficiency of rest we must include them in our diet.
• These 10 amino acids which the body cannot synthesize on its own and must be taken from external sources are called essential amino acids

The 10 essential amino acids are-

• Valine, Leucine, Isoleucine, Phenylalanine, Methionine, Tryptophan, Threonine, Lysine, Arginine, and Histidine.

The non-essential amino acids are

•  Glycine, Alanine, Proline, Arginine, Asparagine, Aspartic acid, Cysteine, Tyrosine, Glutamic acid, Glutamine, and Serine.

​Glycine:

• Glycine is a non-essential amino acid.
• Glycine is the simplest amino acid having one amino and one carboxylic functional group. The structure is:

• Glycine is the only amino acid that has no optical activity.
• The function of glycine is the healthy functioning of the central nervous system, acts an anti-oxidant.

Hence, the simplest α-amino acid is Glycine.

CONCEPT:

Stability of Artificial Sweeteners at Cooking Temperature

• Artificial sweeteners are used as sugar substitutes in various food and beverage products. However, not all sweeteners are stable at high temperatures.
• Some sweeteners can break down or lose their sweetness when exposed to heat, making them unsuitable for cooking or baking.

EXPLANATION:

• Aspartame is an artificial sweetener that is known to be unstable at cooking temperatures.
  • When aspartame is heated, it can break down into its constituent components: aspartic acid, phenylalanine, and methanol.
  • This breakdown results in a loss of sweetness and can affect the flavor of the food.
• Other sweeteners like sucralose, alitame, and saccharin are more stable at higher temperatures and can be used in cooking and baking without significant loss of sweetness.
  • Sucralose is especially known for its high heat stability, making it suitable for a wide range of cooking applications.
  • Alitame and saccharin also maintain their sweetness when exposed to heat.

Therefore, the correct answer is option 2: Aspartame.

Explanation:

Tollen's reagent-

• Tollens Test is a very useful method to distinguish between aldehydes and ketones. This qualitative lab test is also referred to as the silver mirror test.
• Tollens Reagent refers to the chemical reagent used to detect an aldehyde functional group, an aromatic aldehyde functional group, or an alpha-hydroxy ketone functional group in a given test substance.
• Tollens test is generally given by compounds having an aldehydic group (aldehydes,alpha-hydroxy ketones, and formic acid-its -COOH behaves like an aldehydic group). It gives a white ppt of Silver (where the silver salt is reduced to silver metal and the aldehyde is oxidized to silver salt of carboxylic acid.

Given data and Analysis-

⇒ Aldehydes are oxidized easily but ketones do not quickly oxidize by Tollen's agent.

⇒ Only aldehydes can reduce Tollen’s reagent.

⇒ Fructose is a Ketone, so fructose is kept in an aqueous solution and enolized. And then converted into aldehyde in the basic medium or by the base.

⇒ The reaction of aldehydes with Tollen’s reagent is an oxidation reaction.

⇒ All aldehydes generally reduce Tollen's reagent.

⇒ It can be concluded that fructose reduces Tollen’s reagent due to the enolization of fructose followed by conversion to aldehyde by the base.

The correct answer is proteins.

• The building blocks of proteins are amino acids.

Important Points

• Amino acids:
  • Proteins are made up of organic compounds called amino acids. So they are known as the building components of proteins.
  • Amino acids are the necessary ingredients for the growth and development of human.
  • Basic amino groups (-NH₂) and carboxyl groups (-COOH) are found in amino acids.
  • Long chains of amino acids constitute peptides and proteins.
  • Proteins are made up of twenty amino acids.
  • Examples of Amino acids:
    • Histidine, Isoleucine, Leucine, Lysine
  • Figure: Structure of Amino acid

Additional Information

• Carbohydrates:
  • Carbohydrates are organic compounds in which the ratio of Carbon, Hydrogen and Oxygen is 1:2:1.
  • Carbohydrate in the form of sugar and starch are major intake in animals and humans.
  • Carbohydrate containing aldehyde group is called aldose and with ketone group is called ketose.
  • Carbohydrates are derivatives of polyhydroxy alcohols.
• Vitamins:
  • Vitamin was invented by Sir F. G. Hopkins.
  • The term vitamin was coined by Funk.
  • Vitamins are organic compounds required in minute quantities.
  • No calorie is obtained from it, but it is very important in regulating chemical reactions in the metabolism of the body.
• Minerals:
  • The mineral is a homogenous inorganic material needed for the body which controls the metabolism of the body.

The correct answer is Amino acids.

Key Points

• Amino acids are organic compounds containing an amino group and an acidic group as substituents on the same carbon.
• Amino acids contain amino and carboxyl functional groups.
• Amino acids are the building block of protein molecules.
• It is obtained by the hydrolysis of proteins.
• Most naturally occurring amino acids have L-configuration.

Important Points

• Proteins are made up of carbon, hydrogen, oxygen, and nitrogen.
• Protein helps in the building up of the human body.
• Protein serves as a source of energy during starvation.
• Proteins are linear chains of amino acids linked by peptide bonds.
• Each protein is a polymer of amino acids.

Additional Information

• Fats are composed of fatty acids and glycerol.
• Ethanoic acid is commonly called acetic acid and belongs to carboxylic acids.
• Formic acid is the acid present in ants.

Sugarcane contains Glucose + Fructose.

• Fructose is a monosaccharide.
•  A monosaccharide is the simplest form of sugar and the smallest unit of carbohydrate which cannot be further divided.
• When two monosaccharides join it forms a molecule called Disaccharide.
• All the other options are disaccharides

The correct answer is Sucralose.

Key Points

• Sucralose is known as a zero-calorie sugar.

• Some other forms of sugar:
• Saccharin:
  • A sweetish crystalline solid which is 550 times sweeter than sugar, but does not have any food value.
  • It is used by diabetic patients.
  • It is the first discovered artificial sweetener.
• Aspartame:
  • It is used in cold drinks and ice-creams.
  • It is also known as Nutra sweet.
• Alitame:
  • It is 2000 times sweeter than sucrose.
• Cyclamate:
  • It is 20 times sweeter than cane sugar.
• Dulcin:
  • It is 25 times sweeter than cane sugar.

Notes:

• Monosaccharides are simple sugars with a single sugar unit.
  • Glucose - Blood sugar
  • Fructose
  • Galactose
• Disaccharides are Compound sugars with two sugar units.
  • Sucrose – sugar cane and sugar beets
  • Maltose
  • Lactose – Milk sugar

• Polysaccharides are complex sugars with many sugar units.
  • Whole grains, Fruits and Vegetables contain these type of complex sugars.
• Glucose is blood sugar.
• Excess glucose is stored in the body as glycogen.
• Glycogen is stored in the liver and muscles.
• The body can store about ½ day supply of glycogen for energy.

Concept:

Vitamins:

• Vitamins are organic compounds that are present in minute amounts in natural foodstuffs.
• Most vitamins come from food because the body either does not produce them or produces very little.
• Vitamins are of two types.
  • Fat-soluble vitamins- Vitamins A, D, E, K.
  • Water-soluble vitamins- Vitamin C and all the B vitamins. 

• There are 13 vitamins - A, C, D, E, K, and B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, B6, B12, and folate), each of them have a different job.
• Vitamin A, D, E, K are Fat-Soluble vitamins and are stored in fat cells while vitamins B and C are water-soluble vitamins that are not stored in your body.
• The liver acts as a storage site for vitamin A, D, E, K, and B12 for the times when they may be lacking in the diet.
• Vitamin D acts as a hormone, produced by the kidneys it helps to control the concentration of calcium in the blood and is vital for the development of strong bones.
• Water-soluble vitamins like Thiamine, folate, biotin, riboflavin are synthesized by gut bacteria.

Explanation:

• Vitamin E is a mixture of four vitamins called α, β, γ and δ tocopherols among which α tocopherol is the most active.
• Characteristics:
  • Light yellow fat soluble in oils.
  • Stable to heat and oxidation.
• Sources are cotton seed oil, maize oil, peanut oil and wheat germ oil.
• Deficiency causes damage to the reproductive system.

Hence, Vitamin E is also called tocopherol.

Additional Information

• Riboflavin is vitamin B₂.
• Calciferol is vitamin D.
• Thiamine is vitamin B₁.

The correct answer is Antacid.

Key Points

• Antacid:
  • Antacids are medicines that counteract (neutralise) the acid in your stomach to relieve indigestion and heartburn.
  • Antacids may help if you have: 
    • Indigestion
    • Heartburn or acid reflux – also known as gastro-oesophageal reflux disease (GORD)
    • Stomach ulcer
    • Gastritis (inflammation of the stomach lining) 

Additional Information

• Antibiotic:
  • These are medications that destroy or slow down the growth of bacteria. 
  • Antibiotics are used to prevent and treat bacterial infections.
• Analgesic:
  • Analgesics, also called painkillers, are medications that relieve different types of pain from headaches to injuries to arthritis.
  • Anti-inflammatory analgesics reduce inflammation, and opioid analgesics change the way the brain perceives pain. 
• Antiseptic:
  • An antiseptic is a substance that stops or slows down the growth of microorganisms.
  • They are frequently used in hospitals and other medical settings to reduce the risk of infection during surgery and other procedures.

The correct answer is Ascorbic acid.

Key Points

• Vitamin C, also known as ascorbic acid or L-ascorbic acid.
• The richest sources of ascorbic acid including Indian gooseberry, citrus fruits such as limes, oranges, and lemons, tomatoes, potatoes, papaya, green and red peppers, kiwifruit, strawberries, etc.
• Deficiency of Vitamin C and iron often occur in anemia.

Additional Information

• Citric acid is found naturally in citrus fruits, like lemons and limes.
  • It gives them their tart, sour taste.
• Lactic acid is a natural organic acid, found in milk and other food products such as meat and beer.
  • It is used in the food industry as a preservative, flavor enhancer, and acid adjustment.
• Folate and folic acid are forms of a water-soluble B vitamin.
  • Folate, also known as vitamin B₉ and folacin.
• Organic acids like oxalic acid, citric acid, and malic acid present in tomatoes.

The correct answer is Sucrose.

Key Points

• Non-reducing sugars are compounds that cannot be reduced to other compounds.
• They do not have an OH group attached to the anomeric carbon.
• All monosaccharides such as glucose are reducing sugars.
• A disaccharide can be a reducing sugar or a non-reducing sugar.
• Maltose and lactose are reducing sugars.
• Sucrose is a non-reducing sugar.
• Reducing sugars can be reduced to other compounds.

Additional Information

​About Sugar:

• Sugars are soluble carbohydrates. 
• They are sweet-tasting, many of which are used in food.
• There are mainly two types of sugar, i.e simple sugars and compound sugar.
• Simple sugars, also called monosaccharides, includes glucose, fructose, and galactose.
• Compound sugars, also called disaccharides or double sugars, are molecules composed of two monosaccharides joined by a glycosidic bond. Common examples are sucrose, lactose, and maltose.

Concept:

Key Points

Nucleic acids:

• The role of nucleic acids is to see how carbohydrates, proteins, and enzymes originate in the cell and how they preserve their structural formation.
• Nucleic acids are defined as the long-chain polymers present in high concentrations in the nuclei of cells in which the monomeric units are nucleotides.
• The molecules where one of the bases is combined with sugar is called nucleoside.
• When a phosphate group is also attached to the nucleoside, it is called a nucleotide.
• Nucleic acids are responsible for the biosynthesis of proteins and the transmission of hereditary characters.

Explanation:

• There are two types of nucleic acids DNA, RNA.
• DNA molecules are very large and are found in the nucleus of the cell.
• On the other hand, RNA molecules are much smaller and are found outside the cell.
• DNA stands for de-oxy ribonucleic acid. It has a double helix structure.

• DNA contains nitrogenous bases, a pentose sugar, and phosphate.
• Two types of nitrogenous bases are there- Purines and pyrimidines.
• The pentose sugar is given below:

Hence, in DNA, a pentose sugar is present.

Additional Information

•  The complete hydrolysis of DNA yields β-D-2-deoxyribose, phosphoric acid, and adenine.
•  Partial hydrolysis of DNA yields deoxy Adenosine and phosphoric acid.

Option 3 is correct, i.e. Proteins are not affected by temperature.

● Heat can be used to break the hydrogen bonds and hydrophobic non-polar interactions. 

● It occurs because heat increases the kinetic energy and allows the molecules to vibrate so quickly and violently that they break the bonds. The proteins in the eggs coagulate and denature while cooking.

● Hence, it implies that the heat (temperature) affects the protein.