Class 11 Biology - ODISHA
Cell: The Unit of Life
The chapter 'Cell: The Unit of Life' forms the foundation of cell biology, explaining the structure and functional significance of cells as the basic building blocks of all living organisms. Students in Odisha (BSE) Class 11 will explore the Cell Theory, the distinction between prokaryotic and eukaryotic cells, and the detailed architecture of plant and animal cells. Topics cover cell membrane models like the fluid mosaic model, endomembrane system, mitochondria, chloroplasts, ribosomes, and the nucleus. Mastering this chapter is crucial for board exams as it carries high weightage and serves as a prerequisite for understanding advanced physiological and genetic processes.
Start Learning FreeKey Concepts
Cell Theory
Formulated by Schleiden, 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 true membrane-bound nucleus and distinct organelles (e.g., bacteria), whereas eukaryotic cells possess a well-defined nucleus and membrane-bound organelles (e.g., plant and animal cells).
Fluid Mosaic Model
Proposed by Singer and Nicolson, this model describes the plasma membrane as a quasi-fluid phospholipid bilayer with proteins embedded in it, allowing lateral movement of molecules.
Endomembrane System
A coordinated network of membranous organelles including the Endoplasmic Reticulum (ER), Golgi apparatus, lysosomes, and vacuoles that function together in protein synthesis, modification, and transport.
Mitochondria and Plastids
Mitochondria act as the 'powerhouses of the cell' producing ATP via cellular respiration, while plastids like chloroplasts are responsible for photosynthesis in plant cells.
Important Formulas
Board Exam Info
In the Odisha (BSE) Class 11 biology examinations, this chapter typically carries around 6 to 8 marks. Questions frequently include diagram-based questions (like the ultrastructure of a plant/animal cell or mitochondria), short-answer questions on cell organelles and their functions, and differences between prokaryotes and eukaryotes.
Frequently Asked Questions
Because every living organism is made up of cells, and all the metabolic and physiological life processes (like respiration, digestion, and excretion) occur inside these cells.
Because every living organism is made up of cells, and all the vital metabolic and physiological processes necessary for life occur inside them.
What is the difference between 70S and 80S ribosomes?
70S ribosomes are smaller and found in prokaryotic cells, mitochondria, and chloroplasts, whereas 80S ribosomes are larger and found in the cytoplasm of eukaryotic cells.
Why are lysosomes known as suicidal bags?
Lysosomes contain powerful digestive enzymes capable of breaking down cellular debris; when a cell is damaged or dying, these enzymes burst out and digest the entire cell.
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