Chemistry of Natural Products MCQ Quiz in मल्याळम - Objective Question with Answer for Chemistry of Natural Products - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

Concept:-

Terpene:

• Terpenes are unsaturated compounds formed by joining together isoprene units.
• Terpenes are components of a wide variety of fruit and floral flavours and aromas. These derivatives are responsible for the distinctive aroma of spices.
• Terpenes contain carbon atoms in multiples of five They are made by joining together 5-carbon isoprene units. Oxygen-containing terpenes are sometimes called terpenoids.

Terpene structure:

• The terpene structure can contain one or more isoprene units. In the terpene structure, the unsaturation and functional groups can vary depending on the nature of the compound. Terpenes can be classified on the basis of the isoprene units they contain.
  1. Monoterpene- These molecules contain two isoprene units.
  2. Sesquiterpenes- These molecules contain three isoprene units.
  3. Diterpenes- These molecules contain four isoprene units.
  4. Triterpenes- These molecules contain six isoprene units.
• Camphor is a waxy, colorless solid with a strong aroma. It is classified as a terpenoid and a cyclic ketone.

• Terpenes are hydrocarbons made up of repeating units of a 5-carbon molecule called isoprene. Terpenoids, on the other hand, are modified terpenes that have undergone chemical transformations. Camphor is considered a terpenoid because it is derived from the terpene called pinene through a series of chemical reactions.

Flavonoids:

• Flavonoids are a diverse class of polyphenolic compounds widely distributed in the plant kingdom. They are known for their various biological activities and contribute to the colors of many fruits, vegetables, and flowers. The structural features of flavonoids include several key elements:

1. Basic Structure:

   • Flavonoids have a basic structure consisting of 15 carbon atoms arranged in three rings (C6-C3-C6):
     • A benzene ring (ring A) is attached to a heterocyclic pyran ring (ring C) and a benzene ring (ring B).
     • Ring A is usually connected to Ring B by a carbon-carbon bridge, forming a phenylbenzopyran structure.
     • The pyran ring (ring C) is often oxygenated.

2. Rings and Hydroxylation:

   • Ring A: Benzene ring, often hydroxylated.
   • Ring B: Benzene ring, can be hydroxylated and may contain other substituents.
   • Ring C: Heterocyclic pyran ring,

Explanation:-

• Compound B is a derivative of camphor.
• Thus, only Compound B is a terpene derivative.

Conclusion:-

• Hence, the compound that can be classified as a terpene derivative is B only.

Explanation:

• DNA is the polymer of nucleotides. 
• Deoxyribonucleic acid ( DNA) is the molecule that carries the genetic information for the development and functioning of an organism.
• DNA is made of two linked strands that wind around each other to resemble a twisted ladder, a shape known as a double helix.
• Each DNA molecule consists of two nucleotide chains wrapped around each other in a double helix and held together by hydrogen bonds.
• This hydrogen bonding involves only the nitrogenous bases. Each of the purine bases can hydrogen bond with one and only one of the pyrimidine bases.
• nucleotides contain 3 components: a nitrogenous base ( A, T, G, C), a pentose sugar, and a phosphate group. 
• The bases are named adenine (A), thymine (T), cytosine (C), and guanine (G).
• The reason for the double-helical structure of DNA is the operation of Hydrogen bonding.

Explanation:-

 (Adenine)

(Thymine)

Concept:-

• Glucose is a simple sugar with six carbon atoms and one aldehyde group. This monosaccharide has a chemical formula C6H12O6.
• Glucose is an aldohexose and is also known as dextrose.
• The structure of D- (+) -glucose is

• It is the monomer of many of the larger carbohydrates, namely starch, and cellulose.

Explanation:-

• The reaction pathway is shown below:

Conclusion:-

• Hence, the product of the following reaction is n-heptanoic acid.

The chemical reaction involved in the above transformation can be illustrated as

Explanation:-

The biosynthetic pathway of a natural product involves a series of enzymatic reactions that transform simpler molecules into more complex compounds. In the case of a natural product whose biosynthetic precursors are phenylalanine and acetyl CoA, it likely involves the synthesis of a compound with a phenylalanine-derived aromatic ring and acetyl CoA-derived acetyl groups. Here's a general overview of how this could work:

• Phenylalanine Biosynthesis: Phenylalanine is an amino acid that serves as the precursor for a variety of aromatic compounds in living organisms. It can be synthesized through a series of enzymatic reactions from simpler precursors. The aromatic ring in phenylalanine can be used as a starting point for the biosynthesis of other aromatic compounds.

• Formation of Aromatic Intermediates: Enzymes can convert phenylalanine into various aromatic intermediates by modifying its structure. These intermediates may undergo reactions such as hydroxylation, decarboxylation, and rearrangement to form different aromatic compounds.

• Incorporation of Acetyl CoA: Acetyl CoA is a central molecule in cellular metabolism, serving as a carrier of acetyl groups. Acetyl CoA can be derived from various metabolic pathways, including glycolysis and fatty acid oxidation. Enzymes can catalyze the transfer of acetyl groups from acetyl CoA to other molecules.

• Synthesis of the Natural Product: Enzymatic reactions can facilitate the incorporation of both phenylalanine-derived aromatic intermediates and acetyl CoA-derived acetyl groups into a growing natural product molecule. The specific reactions and enzymes involved will depend on the nature of the natural product.

• Further Modifications: The biosynthetic pathway may involve additional enzymatic steps to modify the structure of the growing natural product. These modifications could include oxidation, reduction, methylation, and other chemical transformations.

• Final Product Formation: The series of enzymatic reactions ultimately leads to the formation of the final natural product, which could be a secondary metabolite with specific biological activities. The structural complexity and functional groups of the natural product are a result of the combination of phenylalanine-derived aromatic moieties and acetyl CoA-derived acetyl groups.

It's important to note that the specific biosynthetic pathway and the natural product produced will depend on the organism, the enzymes involved, and the specific metabolic pathways present in that organism. The described process provides a general outline of how phenylalanine and acetyl CoA could serve as biosynthetic precursors for a natural product, but the actual details will vary widely depending on the specific biochemical context.

Conclusion:-

Hence, the Biosynthetic precursors of the following natural product are A and C.

Explanation:

Chemical reaction involved in the above transformation can be illustrated as;

Conclusion:-

Hence, the major product formed in the reaction of glucose with benzaldehyde and p-TSA is
 

Concept:-

• Carbohydrates react with phenylhydrazine and form the respective osazone. The Osazone test is used to identify the reducing sugars.
• Glucose reacts with phenyl hydrazine and forms the following osazone:

• Fructose reacts with phenyl hydrazine and forms the following osazone:

Explanation:-

• Tollen's test is a chemical test used to detect the presence of reducing sugars.
• When a reducing sugar is present, such as glucose or fructose, it reacts with Tollen's reagent (ammoniacal silver nitrate) to form a silver mirror or a brown precipitate.
• However, sucrose is a non-reducing sugar because it lacks a free carbonyl group. Therefore, it does not react with Tollen's reagent and gives a negative test result.
• Similarly, the formation of an osazone with phenylhydrazine is a characteristic reaction of reducing sugars.
• D-Galactose, maltose, and D-fructose are reducing sugars and can form osazones when reacted with phenylhydrazine.
• Sucrose consists of two sugars (fructose and glucose) joined by their glycosidic linkage in a way that prevents glucose from isomerizing to an aldehyde, or fructose to the α-hydroxy-ketone form.
• Sucrose is thus a non-catabolizing sugar, which gives a negative Tollen’s test.
• However, sucrose, being a non-reducing sugar, does not undergo this reaction and does not form an osazone.

Conclusion:-

• ​Hence, Sucrose gives a negative Tollens test and will not form osazone with phenylhydrazine.

Concept:

• The chain conformation of D-glucose is responsible for the formation of three native cyclodextrins (CD's), these are α-CD, β-CD, and γ-CD.
• The Schematic representations of CD's are shown below:

• The polar exterior of cyclodextrins (CD's) is known as rim, and can interact with polar functional groups. The interior cavity is hydrophobic as it is lined with non-polar groups, and can interact with non-polar groups.
• The hydrophobic cavity of CD's has the ability to encapsulate, either partially or fully, small organic molecules.
• The hydrophobic cavity of α-CD's is the smallest in size. 

Explanation:

• Cyclodextrins (CD's) can form complexes with a wide range of molecules including branched or cyclic alkyl groups, aromatic molecules, and proteins.
• Interactions between cyclodextrins (host) and guest molecules yield a stable complex with a high equilibrium constant.
• The α-CD can interact with the guest molecule "C" through H-bonding in the exterior (rim). While the hydrophobic cavity can interact with the non-polar part of the guest molecule.

Conclusion:

Hence, the guest molecule which will fit best inside α-cyclodextrin by interacting with both, rim and cavity, is
 

Concept:

Polyketides:

• Polyketides are a class of natural products derived from a precursor molecule, consisting of a chain of alternative ketone and methylene groups. 
• Polyketides contain large groups of secondary metabolites that either contain a chain of alternative ketone and methylene groups or are derived from precursors which contain such alternating groups.

Explanation:

• Muscone is a natural product of the group polyketide.
• Muscone is an organic compound (natural product) that is a primary contributor to the odor of musk.

​Conclusion:

Hence, Muscone is a ​polyketide. 

Explanation:

→ Sucrose molecule is made up of α−D− gluco pyranose and β−D− fructo furanose.

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