Biomolecules Overview

Biomolecules

• Biomolecules are the fundamental building blocks of life. They are large molecules, primarily composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus.
• Four major classes include carbohydrates, proteins, lipids, and nucleic acids.
• Carbohydrates: Provide energy and structural support. Simple sugars (monosaccharides) like glucose combine to form complex carbohydrates like starch and cellulose.
• Proteins: Crucial for structure, function, and regulation. Composed of amino acids linked together. Perform diverse roles like catalyzing reactions (enzymes), transporting molecules, and providing structural support.
• Lipids: Diverse group including fats, oils, and steroids. Important for energy storage, insulation, and hormone production. Fatty acids are a key component.
• Nucleic acids: DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). Carry genetic information, crucial for protein synthesis and cellular processes. DNA stores genetic instructions, while RNA plays a role in protein synthesis and other cellular functions.

Cell Structure and Function

• Cells are the basic units of life. They exhibit varied structures and specialized functions.
• Cell Membrane: A selectively permeable barrier surrounding the cell, controlling what enters and exits. Made of a phospholipid bilayer with embedded proteins.
• Cytoplasm: The jelly-like substance within the cell that houses organelles and facilitates cellular processes.
• Organelles: Specialized structures within the cell performing specific functions. Examples include the nucleus (contains DNA), mitochondria (energy production), ribosomes (protein synthesis), endoplasmic reticulum (protein and lipid synthesis and transport).
• Prokaryotic vs. Eukaryotic Cells: Prokaryotic cells (bacteria and archaea) lack membrane-bound organelles. Eukaryotic cells (animals, plants, fungi, protists) contain membrane-bound organelles.
• Cell Transport: Movement of substances across the cell membrane. Includes passive transport (diffusion, osmosis), active transport (requiring energy), and bulk transport (endocytosis, exocytosis).
• Cellular Respiration: The process by which cells break down nutrients to release energy for cellular functions. Most often involves oxygen and produces ATP.
• Cell Signaling: Processes by which cells communicate with each other to coordinate functions and responses. Receptors and signal transduction pathways are involved.

Tissues

• Tissues are groups of similar cells working together to perform a specific function. Four primary tissue types:
• Epithelial Tissue: Covers surfaces, lines cavities, and forms glands. Functions include protection, secretion, absorption, and excretion. Characterized by tightly packed cells with little extracellular matrix.
• Connective Tissue: Supports, connects, and separates different tissues. Diverse types including bone, cartilage, tendons, ligaments, and blood. Characterized by a large amount of extracellular matrix.
• Muscle Tissue: Responsible for movement. Three types: skeletal (voluntary), smooth (involuntary), and cardiac (heart muscle).
• Nervous Tissue: Carries electrical signals throughout the body. Composed of neurons (transmit signals) and glial cells (support neurons).

Cell Organisation

• Cells: Basic units of life.
• Tissues: Groups of similar cells.
• Organs: Structures composed of two or more tissue types working together.
• Organ Systems: Groups of organs working together to perform a complex function (e.g., digestive, respiratory).
• Organisms are complex systems with various levels of organization from cells to entire body systems. Cell specialization is key to the efficient functioning of multicellular organisms, contributing to the structural and functional diversity of body systems.