Biología Celular: Estructura y Función

Cell Biology: Overview

• Cells are the basic structural and functional units of all living organisms.
• Cells show a remarkable diversity in size, shape, and function, but all share fundamental characteristics such as a plasma membrane, cytoplasm, and genetic material.
• Cells are categorized as prokaryotic (lacking a nucleus and membrane-bound organelles) or eukaryotic (possessing a nucleus and membrane-bound organelles).

Cell Structure

• Plasma Membrane: A selectively permeable phospholipid bilayer that encloses the cell and regulates the passage of molecules in and out.
  • Contains proteins embedded for various functions, including transport, signaling and enzymatic activity.
  • Fluid mosaic model describes the dynamic nature of membrane components.
• Cytoplasm: The region between the plasma membrane and the nucleus containing organelles and cytosol (fluid part).
• Nucleus: The control center of the cell, containing genetic material (DNA) organized into chromosomes.
• Ribosomes: Sites of protein synthesis, found free in the cytoplasm or attached to the endoplasmic reticulum.
• Endoplasmic Reticulum (ER): A network of membranes involved in protein synthesis, lipid synthesis, and calcium storage.
  • Rough ER: Studded with ribosomes, involved in protein modification and folding.
  • Smooth ER: Involved in lipid synthesis and detoxification.
• Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion or intracellular use.
• Mitochondria: The "powerhouses" of the cell, responsible for cellular respiration and energy production (ATP).
• Lysosomes: Contain digestive enzymes that break down cellular waste and foreign matter.
• Vacuoles: Membrane-bound sacs involved in storage, transport, and maintaining turgor pressure (primarily in plant cells).
• Peroxisomes: Contain enzymes for various metabolic reactions, including lipid breakdown and detoxification.
• Cytoskeleton: A network of protein filaments (microtubules, microfilaments, intermediate filaments) that maintain cell shape, support cellular movement, and facilitate intracellular transport.
• Centrosomes: Contain centrioles, involved in cell division and microtubule organization.

Cell Function

• Metabolism: The sum of all chemical reactions occurring in a cell, including anabolism (building complex molecules) and catabolism (breaking down complex molecules).
• Transport: Movement of substances across the plasma membrane, including passive transport (diffusion, osmosis), facilitated diffusion, and active transport.
• Signaling: Communication between cells via various signaling pathways, crucial for coordination and regulation.
  • Cell signaling often involves hormones, neurotransmitters, and other molecules.
• Gene Expression: The process of using DNA information to synthesize proteins.
• Growth and Development: Cell division and specialization during the life of an organism.

Cell Division

• Mitosis: A process of cell division resulting in two genetically identical daughter cells crucial for growth, repair, and asexual reproduction.
  • Stages include prophase, metaphase, anaphase, and telophase.
• Meiosis: A specialized type of cell division resulting in four genetically diverse daughter cells, each with half the number of chromosomes (critical for sexual reproduction)
  • Two rounds of cell division result in genetic variation.
• Cell Cycle: An ordered sequence of events in the life of a cell, consisting of interphase (G1, S, G2) and the mitotic (M) phase.
  • Crucial for regulating cell growth, DNA replication, and division.
• Control Mechanisms: Mechanisms to regulate cell growth and divisions, often regulated at checkpoints to ensure accuracy prevent uncontrolled proliferation (cancer).

Este cuestionario abarca los conceptos fundamentales de la biología celular, explorando los distintos tipos de células y sus estructuras esenciales. Aprenderás sobre la membrana plasmática, el citoplasma y el núcleo, así como la clasificación de las células en procariotas y eucariotas. ¡Ponte a prueba con estos conocimientos sobre la vida a nivel celular!