Class 11 Biology - PUNJAB
Biomolecules
The chapter 'Biomolecules' in Class 11 Biology explores the chemical and metabolic foundation of living organisms, focusing on the building blocks of life as prescribed by the Punjab School Education Board (PSEB). Students will study the structural and functional roles of carbohydrates, proteins, lipids, nucleic acids, and enzymes. Understanding these organic molecules is crucial for comprehending cellular metabolism and genetics. This chapter holds high weightage in board exams, frequently featuring direct questions on macromolecule structures, enzyme action, and metabolic pathways, making it essential for scoring high marks and building a strong medical entrance foundation.
Start Learning FreeKey Concepts
Carbohydrates
Polyhydroxy aldehydes or ketones acting as primary energy sources, classified into monosaccharides, oligosaccharides, and polysaccharides like cellulose and starch.
Proteins
Complex polymers of amino acids linked by peptide bonds, essential for structural support, transport, and acting as biological catalysts.
Lipids
Water-insoluble biomolecules composed of fatty acids and glycerol, serving as long-term energy storage and major components of cell membranes.
Nucleic Acids
Polymers of nucleotides consisting of a pentose sugar, nitrogenous base, and phosphate group, responsible for hereditary information storage (DNA and RNA).
Enzymes
Biocatalysts mostly made of protein that lower the activation energy of biochemical reactions, characterized by active sites and specificity.
Important Formulas
Board Exam Info
In the Punjab (PSEB) Class 11 Biology board examinations, this chapter typically carries around 4 to 6 marks. Common question types include short-answer questions on enzyme action and structures of amino acids, as well as long-answer questions detailing the structure of proteins or nucleic acids.
Frequently Asked Questions
What is the difference between reducing and non-reducing sugars?
Reducing sugars have free aldehyde or ketone groups that can reduce tolleh's or fehling's reagent (e.g., glucose, maltose), whereas non-reducing sugars like sucrose do not have free reactive groups.
Why are lipids not strictly considered polymers?
Unlike carbohydrates, proteins, and nucleic acids which are formed by repeating monomer units, lipids are assembled from smaller precursor molecules like fatty acids and glycerol rather than continuous identical chains.
How do competitive and non-competitive enzyme inhibitors differ?
Competitive inhibitors resemble the substrate and bind to the active site, while non-competitive inhibitors bind to an allosteric site, changing the enzyme's shape and rendering it inactive regardless of substrate concentration.
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