Class 11 Biology - KERALA
Cell: The Unit of Life
The chapter 'Cell: The Unit of Life' forms the foundational core of Class 11 Biology under the Kerala SCERT syllabus. It introduces students to the cell theory, the structural differences between prokaryotic and eukaryotic cells, and the detailed architecture of plant and animal cells. You will explore the structure and functions of various cell organelles such as the plasma membrane, mitochondria, ribosomes, and the nucleus. Mastering this chapter is crucial for Kerala Board exams as it carries high weightage, frequently featuring in both direct descriptive questions and diagram-based evaluations, laying the groundwork for upcoming chapters on plant and human physiology.
Start Learning FreeKey Concepts
Cell Theory
Formulated by Schleiden and Schwann, and later modified by Rudolf Virchow, it states that all living organisms are composed of cells and products of cells, and all cells arise from pre-existing cells.
Prokaryotic vs Eukaryotic Cells
Prokaryotic cells lack a membrane-bound nucleus and distinct organelles (e.g., bacteria), whereas eukaryotic cells possess a true nucleus and membrane-bound organelles (e.g., plant and animal cells).
Plasma Membrane Structure
Described by the fluid mosaic model proposed by Singer and Nicolson, it consists of a lipid bilayer with embedded proteins that provide fluidity and selective permeability.
Endomembrane System
A group of interconnected membrane organelles including the endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles whose functions are coordinated.
Mitochondria and Plastids
Semi-autonomous organelles containing their own DNA and ribosomes; mitochondria are the powerhouse of the cell, while plastids are found in plant cells for photosynthesis and storage.
Important Formulas
Board Exam Info
In the Kerala (SCERT) Class 11 Biology board examinations, this chapter typically carries around 6 to 8 marks. Questions frequently include labeling diagrams (like plant/animal cell or chloroplast), direct structural and functional differences between prokaryotes and eukaryotes, and short notes on specific cell organelles.
Frequently Asked Questions
Why are mitochondria called the powerhouse of the cell?
Mitochondria produce cellular energy in the form of ATP (Adenosine Triphosphate) through aerobic respiration.
What is the main difference between plant and animal cells?
Plant cells have a rigid cell wall, large central vacuoles, and plastids, which are absent in animal cells.
Who proposed the fluid mosaic model of the plasma membrane?
S.J. Singer and G.L. Nicolson proposed the fluid mosaic model in 1972.
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