Carbohydrates

Carbohydrates

Which sugar is a precursor in nucleotide synthesis?

Structural role in extracellular matrix is the correct answer because it serves as the specific precursor, synthetic product, or metabolic intermediate described in this question. Biosynthetic pathways in Carbohydrates follow precise enzymatic steps where specific substrates are converted to products through regulated metabolic reactions. Structural role in extracellular matrix occupies a key position in this metabolic pathway due to its chemical structure and reactivity. The other options (Energy storage, Formation of peptide bonds, and Regulation of lipid metabolism) are involved in different biosynthetic routes, serve as precursors for different end products, or participate in unrelated metabolic conversions.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

What is the major function of chitin in arthropods?

Mannose accurately defines or describes the concept asked in this question. Within Carbohydrates, precise definitions and terminology are essential for clear scientific communication. The other options (Ribose, Sorbitol, and Xylitol) either describe related but distinct concepts, use incorrect terminology, or confuse similar-sounding terms that have different scientific meanings. A thorough understanding of exact definitions helps distinguish between closely related biological concepts and is crucial for competitive examinations.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

The sugar moiety in DNA differs from RNA by:

They lack an aldehyde group is the scientifically accurate answer to this question. Within the study of Carbohydrates, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of They lack an aldehyde group directly address what is being asked. Among the other options, They always exist in cyclic form, They contain an amino group, and They are non-reducing do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

Which sugar acid results from oxidation of both terminal groups?

Maltose correctly describes the effect or change asked about in this question. In Carbohydrates, understanding cause-and-effect relationships is essential for predicting biological outcomes. Maltose occurs because of specific molecular interactions, thermodynamic principles, or regulatory mechanisms that govern this biological process. The other options (Fructose, Glucose, and Galactose) describe either opposite effects, effects that occur under different conditions, or changes associated with unrelated processes.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

Which disaccharide contains an α(1→1) glycosidic bond?

Aldaric acid accurately describes the structural composition or molecular organization asked about in this question. In Carbohydrates, knowledge of molecular structure is directly linked to understanding biological function. The specific arrangement of chemical components in Aldaric acid determines its physical properties, biological activity, and interactions with other molecules. The other options (Aldonic acid, Uronic acid, and Lactonic acid) describe different structural arrangements, incorrect stoichiometry, or compositions of different biological molecules.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

The function of proteoglycans is:

Providing hydration and structural support to tissues is the accurate answer because it correctly identifies the biological function or role described in this question. In Carbohydrates, understanding the specific functions of molecules, enzymes, or structures is fundamental. Providing hydration and structural support to tissues fulfills this particular biological role through its specific structural properties, biochemical activity, or physiological mechanism. The other options (Energy storage, Forming peptide bonds, and Transporting lipids) serve different biological functions or are associated with other processes, pathways, or structural roles within the cell or organism.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

The difference between amylose and cellulose is:

Amylose has α(1→4) linkages, cellulose has β(1→4) linkages accurately describes the key difference, similarity, or comparative feature asked about in this question. In Carbohydrates, the ability to compare and contrast related concepts is essential for deeper understanding. The distinguishing feature described by Amylose has α(1→4) linkages, cellulose has β(1→4) linkages reflects fundamental differences in structure, function, mechanism, or origin between the compared entities. The other options (Amylose is found in animal tissues, cellulose in plants, Cellulose is used for energy storage, amylose is for structural support, and Cellulose is a reducing sugar, amylose is non-reducing) either state incorrect comparisons, confuse the properties of the entities being compared, or describe features that are actually shared rather than different.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

Which glycosidic bond is not found in starch?

β(1→6) is the correct choice because it does not accurately describe or belong to the category addressed in this question. In the context of Carbohydrates, the other options (α(1→4), β(1→4), and Both (a) and (b)) are all valid and well-established concepts. β(1→6) is either unrelated to the topic, describes a different biological process, or represents a common misconception. Questions framed as 'which is NOT' require students to identify the exception among otherwise correct statements, demanding comprehensive knowledge of the topic rather than recognition of a single fact.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

What type of sugar is fructose?

Ketose is the accurate classification or categorization for the organism, molecule, or concept described in this question. In Carbohydrates, proper classification is based on shared characteristics including morphological, biochemical, genetic, and evolutionary criteria. Ketose meets the specific diagnostic features and defining criteria that distinguish it from related groups. The other options (Aldose, Disaccharide, and Polysaccharide) belong to different taxonomic groups, represent different classification levels, or possess distinct characteristics that exclude them from this category.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

Which enzyme hydrolyzes lactose into glucose and galactose?

Lactase is the accurate response regarding enzymatic activity or regulation described in this question. Enzymes are biological catalysts that accelerate reactions by lowering activation energy through specific substrate binding and transition state stabilization. In the context of Carbohydrates, Lactase plays a specific catalytic or regulatory role determined by its active site configuration and mechanism of action. The other options (Amylase, Sucrase, and Cellulase) are either different enzymes with distinct substrate specificities, act through different mechanisms, or are involved in separate metabolic pathways.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

What is the primary function of glycogen in animals?

Energy storage accurately defines or describes the concept asked in this question. Within Carbohydrates, precise definitions and terminology are essential for clear scientific communication. The other options (Structural support, Enzyme activation, and Protein synthesis) either describe related but distinct concepts, use incorrect terminology, or confuse similar-sounding terms that have different scientific meanings. A thorough understanding of exact definitions helps distinguish between closely related biological concepts and is crucial for competitive examinations.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details

Carbohydrates

In Fischer projection, D and L configurations are based on:

The orientation of the hydroxyl (-OH) group at the penultimate carbon is the scientifically accurate answer to this question. Within the study of Carbohydrates, this concept is well-established through extensive research and is documented in standard scientific literature. The specific properties, mechanisms, or characteristics of The orientation of the hydroxyl (-OH) group at the penultimate carbon directly address what is being asked. Among the other options, The rotation of plane-polarized light, The presence of an aldehyde or ketone group, and The number of chiral centers in the molecule do not correctly answer this question because they either refer to different concepts, describe properties of other molecules or processes, or represent common misconceptions about this topic.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 7

View Details