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 Ribosomes CBSE Class 11: MCQs, Case Study & Assertion Reason Questions  Structure and function of ribosomes showing 70S and 80S subunits involved in protein synthesis.   - Dr.Sanjaykumar Pawar  Ribosomes  1. What are Ribosomes? Ribosomes are tiny granular (grain-like) structures present inside cells. They were first observed under an electron microscope. They were discovered by in 1953 . Under the electron microscope, they appear as dense particles. 2. Composition of Ribosomes Ribosomes are made up of: Ribosomal RNA (rRNA) Proteins Therefore, ribosomes are ribonucleoprotein particles . 3. Membrane Around Ribosomes Ribosomes are not surrounded by any membrane . Hence, they are called non-membranous cell organelles . 4. Function of Ribosomes Ribosomes are the site of protein synthesis . They help in translating genetic information into proteins. Therefore, ribosomes are known as the "Protein Factories of the Cell." Types of Ribos...

Difference Between Prokaryotic and Eukaryotic Cells: NEET Notes for Beginners Comparison of Prokaryotic and Eukaryotic Cells with key structures explained for NEET Biology preparation. - Dr.Sanjaykumar Pawar  Bacterial Cell Structures (Continuation) Some bacterial membrane extensions help in: Cell division (formation of daughter cells) DNA replication and distribution Respiration Secretion processes Increasing surface area of plasma membrane Increasing enzyme content Chromatophores (in some bacteria) Found in cyanobacteria They are membrane extensions inside cytoplasm Contain photosynthetic pigments Help in photosynthesis Movement in Bacteria Some bacteria are motile (can move) Some are non-motile (cannot move) Flagella Long, thin, thread-like structures outside cell wall Help in movement (motility) Present only in motile bacteria Structure of flagellum Made of 3 parts: Filament → longest outer part Hook → connects filament to basal body ...