Final answer:
The cell membrane is a selectively permeable barrier with a phospholipid bilayer. Within the cell, various organelles like the ER, Golgi apparatus, lysosomes, mitochondria, peroxisomes, and the cytoskeleton perform specific functions. Cellular communication occurs via signals received by membrane proteins.
Step-by-step explanation:
Cell Membrane Structure
The cell membrane, also known as the plasma membrane, forms a protective barrier around the cell, separating its internal components from the extracellular environment. It is primarily made up of a phospholipid bilayer which has hydrophobic tails and hydrophilic heads. The cell membrane is selectively permeable, using passive and active transport processes to regulate the in and out movement of different substances such as ions, nutrients, and water.
Organelles and Their Functions
The cell's cytoplasm is filled with organelles, each performing specific functions. The endoplasmic reticulum (ER), with its rough and smooth types, is involved in protein synthesis and lipid metabolism, respectively. The Golgi apparatus modifies and packages proteins, while lysosomes contain enzymes for digestion. Mitochondria are the powerhouses of the cell, generating ATP, and peroxisomes break down fatty acids and detoxify harmful substances. The cytoskeleton provides structural support with its microtubules, intermediate filaments, and microfilaments.
Cellular Communication
Cells communicate through their cell membrane by signal reception using membrane proteins that relay information to the cell's interior, allowing it to respond appropriately to various stimuli. This process is essential for coordinating the activities of cells in multicellular organisms.