Class 11 Biology - TELANGANA
Cell: The Unit of Life
The chapter 'Cell: The Unit of Life' forms the foundation of biology for Class 11 students under the Telangana (TSBSE) curriculum. It introduces the Cell Theory and explores the fundamental structural and functional unit of all living organisms. Students will study the detailed architecture of both prokaryotic and eukaryotic cells, differentiating between plant and animal cells. Key cellular organelles such as the plasma membrane, endoplasmic reticulum, Golgi apparatus, mitochondria, ribosomes, and nucleus are examined regarding their structure and biological functions. Mastering this chapter is crucial for board exams as it builds the base for advanced physiological and genetic topics.
Start Learning FreeKey Concepts
Cell Theory
Formulated by Schleiden, Schwann, and later expanded by Rudolf Virchow, it states that all living things are composed of cells and pre-existing 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., plants and animals).
Plasma Membrane Structure
Described by the fluid mosaic model proposed by Singer and Nicolson, it consists of a lipid bilayer with embedded proteins that regulate the selective movement of substances.
Endomembrane System
A coordinated network of membranous organelles including the endoplasmic reticulum, Golgi apparatus, lysosomes, and vacuoles whose functions are coordinated.
Mitochondria and Plastids
Known as the powerhouse of the cell and sites for ATP synthesis, mitochondria (and plastids in plants) contain their own DNA and ribosomes, suggesting an endosymbiotic origin.
Important Formulas
Board Exam Info
In the Telangana (TSBSE) Class 11 Biology board examinations, this chapter typically carries around 6 to 8 marks. Questions frequently include 2-mark very short answer questions (VSAQs) on organelle functions, 4-mark short answer questions (SAQs) on differences between plant and animal cells or prokaryotes and eukaryotes, and occasionally diagram-based labeling questions.
Frequently Asked Questions
What is the difference between prokaryotic and eukaryotic ribosomes?
Prokaryotes contain smaller 70S ribosomes, while eukaryotes contain larger 80S ribosomes in their cytoplasm (though they have 70S ribosomes inside mitochondria and chloroplasts).
Why is the plasma membrane called a fluid mosaic?
It is called 'fluid' because of the quasi-fluid nature of the lipid bilayer that allows lateral movement of proteins, and 'mosaic' due to the protein pattern embedded within it.
Who proposed the Cell Theory and what is its main exception?
Schleiden and Schwann proposed the original cell theory. Viruses are the main exception as they are non-cellular entities lacking cellular machinery outside a host.
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