Cell Biology PDF
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This document provides an overview of prokaryotic and eukaryotic cells. It describes the key differences in structure, function, and reproduction between these two types of cells. The document also discusses common cell components such as the cytoplasm, ribosomes, and the plasma membrane. The importance of eukaryotic cells in multicellular organisms and ecosystems is also highlighted.
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Overview of Cells Cells are the basic units of life, capable of independent existence and reproduction. Two main types of cells: prokaryotic and eukaryotic, distinguished by the presence or absence of a nucleus. Prokaryotic Cells Definition: Unicellular organisms class...
Overview of Cells Cells are the basic units of life, capable of independent existence and reproduction. Two main types of cells: prokaryotic and eukaryotic, distinguished by the presence or absence of a nucleus. Prokaryotic Cells Definition: Unicellular organisms classified in the kingdom Monera, including domains Archaea and Bacteria. Size: Typically range from 1 to 10 micrometers, much smaller than eukaryotic cells. Structure: o Lack a membrane-bound nucleus; genetic material is found in the nucleoid region. o DNA is typically a single circular chromosome, which simplifies genetic engineering. o May have additional features like a capsule or slime layer for protection and attachment. Reproduction: Primarily asexual through binary fission or budding, rapidly producing identical cells. Eukaryotic Cells Definition: More complex cells containing a membrane-bound nucleus and organelles. Size: Generally range from 10 to 100 micrometers; capable of forming multicellular organisms. Structure: o Genetic material is found in multiple linear chromosomes within the nucleus. o Exhibit abundant organelles such as mitochondria, endoplasmic reticulum, and Golgi apparatus, each performing specialized functions. Reproduction: Involves both mitosis for somatic cells and meiosis for gametes (sperm and egg cells). Key Differences Between Prokaryotic and Eukaryotic Cells Nucleus: Eukaryotic cells have a defined nucleus; prokaryotic cells do not. Cell Wall Composition: o Prokaryotes: Composed of peptidoglycan. o Eukaryotes: Plant cells have cellulose, fungi have chitin, while animal cells lack a cell wall. Genetic Material: Prokaryotic DNA is circular; eukaryotic DNA is linear and arranged in pairs. Organelles: Eukaryotes have a variety of membrane-bound organelles, whereas prokaryotes have few or none. Cell Division: Prokaryotes replicate through binary fission; eukaryotes utilize mitosis and meiosis. Common Features Both cell types contain: o Cytoplasm: The entire content within the cell membrane, excluding the nucleus. o Ribosomes: Non-membrane-bound structures that synthesize proteins. o Plasma Membrane: A barrier that separates the cell's interior from the environment. o DNA: Carries genetic instructions for cell functions. Importance of Eukaryotic Cells Eukaryotic cells play critical roles in the formation of complex multicellular organisms, allowing for specialization and division of labor among different cell types. Essential for diverse biological processes like photosynthesis and cellular respiration, contributing to the overall functioning of ecosystems.
