Class 11 Biology - KARNATAKA
Biomolecules
The chapter 'Biomolecules' in Class 11 Biology explores the chemical and metabolic foundation of living organisms. It delves into the structural and functional aspects of chemical compounds found in living tissues, categorizing them into micromolecules and macromolecules. Students will study the building blocks of life, including carbohydrates, proteins, lipids, and nucleic acids, alongside the crucial role of enzymes in metabolic reactions. Understanding this chapter is essential for mastering both cell biology and human physiology, and it consistently carries significant weight in Karnataka (KSEEB) board examinations through direct conceptual and descriptive questions.
Start Learning FreeKey Concepts
Primary and Secondary Metabolites
Primary metabolites like amino acids and sugars have identifiable functions in physiological processes, while secondary metabolites like alkaloids and pigments are products of plant and microbial life with ecological uses.
Proteins and Amino Acids
Proteins are heteropolymers of amino acids linked by peptide bonds, functioning as structural components, enzymes, and hormones critical for life.
Polysaccharides
Complex carbohydrates made of monosaccharide units joined by glycosidic bonds, serving as energy storage (starch, glycogen) and structural support (cellulose, chitin).
Nucleic Acids
DNA and RNA are polynucleotides composed of nitrogenous bases, pentose sugars, and phosphate groups, responsible for genetic information storage and transfer.
Enzymes and Catalytic Activity
Proteins that act as biological catalysts by lowering the activation energy of biochemical reactions, heavily influenced by temperature, pH, and substrate concentration.
Important Formulas
Board Exam Info
This chapter typically carries around 6 to 8 marks in the Karnataka (KSEEB) Class 11 Biology annual examination. Common question types include 1-mark objective questions, 2-mark definitions (e.g., zwitterion, peptide bond), 3-mark short notes on enzyme action or protein structure, and 5-mark descriptive questions on the structure of DNA or classification of enzymes.
Frequently Asked Questions
What is a zwitterion?
It is an amino acid form that exhibits both positive and negative charges simultaneously, existing at the isoelectric pH.
Why are lipids not strictly considered macromolecules?
Because their molecular weights do not exceed 800 Da, though they form cellular structures like membranes and are extracted along with acid-insoluble fractions.
What is the difference between competitive and non-competitive enzyme inhibition?
Competitive inhibitors closely resemble the substrate and bind to the active site, whereas non-competitive inhibitors bind to an allosteric site, altering the shape of the active site.
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