Introducción a las células y sus estructuras

Study Notes

Cells: An Introduction

Cells form the basic structure and functioning units of all living organisms, from simple bacteria to multi-cellular beings like humans. The term 'cell' comes from the Latin word for "room," reflecting their role as the structural and functional units of life. The study of cells is known as cell biology or cytology and is essential to various branches of biology, including genetics and molecular biology.

Cell Theory: A Foundational Concept

The cell theory proposes that all living organisms are composed of one or more cells and that these cells are the fundamental unit of life. This theory also states that cells arise from pre-existing cells through a process called division and that they perform all biological functions necessary for an organism's existence. Scientists Matthias Schleiden and Theodor Schwann first proposed this theory in 1839.

Prokaryotic vs Eukaryotic Cells

Cells can be classified into two main categories based on the presence or absence of a nucleus enclosed by a membrane. Prokaryotic cells do not have a nucleus or other membrane-bound organelles, while eukaryotic cells (found in plants and animals) contain a true nucleus surrounded by nuclear membranes and various specialized organelles that perform specific functions.

Cellular Structures and Functions: Organelles and their roles

Eukaryotic cells are organized into several compartments enclosed in their own lipid bilayer membranes, which we call organelles. These structures play diverse roles in cellular processes such as protein synthesis, energy production, signal transduction, DNA replication and repair, chromatin biology/gene regulation, RNA processing/splicing/modification, mitochondria biology, and glycobiology. Some key organelles include:

Nucleus

This is the control center of a eukaryotic cell, housing genetic information stored as DNA. It also performs essential tasks like regulating gene expression through DNA replication, transcription, and translation.

Mitochondrion

Known as the "powerhouse" of a cell, mitochondria generate most of the ATP (adenosine triphosphate), an energy currency molecule, necessary for cellular activities. They also participate in other crucial physiological processes.

Endoplasmic reticulum (ER)

The ER is responsible for protein synthesis, calcium storage, and lipid synthesis. Two types of ER – smooth endoplasmic reticulum (SER) and rough endoplasmic reticulum (RER) – serve different functions within the cell.

Golgi apparatus

It modifies proteins and lipids produced inside the cell by various organelles, directing them to their correct destinations within the cell.

Lysosomes

These membrane-bound vesicles contain digestive enzymes that break down macromolecules and foreign particles in the cell, ensuring efficient waste removal and recycling of materials.

Understanding these structures and their functions allows us to comprehend the complex workings of life at the cellular level.

Description

Descubre la importancia de las células como unidades fundamentales de los organismos vivos, desde bacterias simples hasta seres multicelulares. Aprende sobre la teoría celular, la diferencia entre células procariontes y eucariontes, y la función de organelos clave como el núcleo, la mitocondria, el retículo endoplasmático, el aparato de Golgi y los lisosomas.