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Chapter Analysis
Advanced21 pages • EnglishQuick Summary
This chapter on Biomolecules covers the structure, classification, and functions of essential biological macromolecules including carbohydrates, proteins, and nucleic acids. It delves into the nature and roles of different saccharides, amino acids, and the structural complexity of proteins. The chapter also discusses the biochemical role of nucleic acids in genetics and protein synthesis and addresses the importance of vitamins as essential nutrients.
Key Topics
- •Classification and properties of carbohydrates
- •Structure and functions of proteins
- •Denaturation and enzyme activity
- •Nucleic acids: DNA and RNA
- •Physiological roles of vitamins
- •Types of RNA and their functions
- •Biochemical importance of amino acids
Learning Objectives
- ✓Understand the chemical nature and classification of biomolecules.
- ✓Explain the structure-function relationship in proteins.
- ✓Describe the roles of carbohydrates in biological systems.
- ✓Understand the structural differences between DNA and RNA.
- ✓Recognize the importance of vitamins and their functions.
- ✓Identify the biochemical significance of nucleic acids.
Questions in Chapter
What are monosaccharides?
Answer: Monosaccharides are carbohydrates that cannot be hydrolysed further to give simpler units of polyhydroxy aldehyde or ketone.
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What are reducing sugars?
Answer: Reducing sugars are those carbohydrates which reduce Fehling's solution and Tollen's reagent.
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Write two main functions of carbohydrates in plants.
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Classify the following into monosaccharides and disaccharides: Ribose, 2-deoxyribose, maltose, galactose, fructose and lactose.
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What do you understand by the term glycosidic linkage?
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What is glycogen? How is it different from starch?
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What are the hydrolysis products of (i) sucrose and (ii) lactose?
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What is the basic structural difference between starch and cellulose?
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What happens when D-glucose is treated with the following reagents? (i) HI (ii) Bromine water (iii) HNO3
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Enumerate the reactions of D-glucose which cannot be explained by its open chain structure.
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What are essential and non-essential amino acids? Give two examples of each type.
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Define the following as related to proteins (i) Peptide linkage (ii) Primary structure (iii) Denaturation.
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What are the common types of secondary structure of proteins?
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What type of bonding helps in stabilising the a-helix structure of proteins?
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Differentiate between globular and fibrous proteins.
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How do you explain the amphoteric behaviour of amino acids?
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What are enzymes?
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What is the effect of denaturation on the structure of proteins?
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How are vitamins classified? Name the vitamin responsible for the coagulation of blood.
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Why are vitamin A and vitamin C essential to us? Give their important sources.
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What are nucleic acids? Mention their two important functions.
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What is the difference between a nucleoside and a nucleotide?
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The two strands in DNA are not identical but are complementary. Explain.
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Write the important structural and functional differences between DNA and RNA.
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What are the different types of RNA found in the cell?
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Additional Practice Questions
Explain the Fischer projection formula for glucose and its significance.
mediumAnswer: Fischer projection is a 2D representation of 3D organic molecules by projection. For glucose, it clarifies the D- and L- configuration based on spatial arrangement of atoms around the chiral center.
Describe the role of enzymes in biochemical reactions.
easyAnswer: Enzymes act as biological catalysts that speed up biochemical reactions by lowering activation energy, ensuring reactions occur efficiently under mild cellular conditions.
What is denaturation of proteins and what are its impacts on protein function?
mediumAnswer: Denaturation involves structural changes in proteins caused by external stress, disrupting hydrogen bonds and leading to loss of biological activity without breaking peptide bonds.
Compare starch and glycogen in terms of their structure and function.
hardAnswer: Starch and glycogen are both polysaccharides; starch is mainly linear or slightly branched (amylose and amylopectin) and serves as energy store in plants, while glycogen is highly branched providing rapid energy release in animals.
Illustrate how the hydrogen bonding contributes to the secondary structure of proteins.
mediumAnswer: Hydrogen bonds form between carbonyl oxygen and amide hydrogen, stabilizing the alpha-helices and beta-pleated sheet structures crucial for protein’s secondary structure.