Cell Structure and Function

Cell Structure and Function

• Cells are the fundamental units of life, exhibiting diverse structures and functions.
• Prokaryotic cells (bacteria and archaea) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (plants, animals, fungi, protists) possess a nucleus and various membrane-bound organelles.
• Plasma membrane: A selectively permeable boundary that regulates the passage of substances into and out of the cell.
• Cytoplasm: The jelly-like substance filling the cell, containing organelles and cytosol.
• Nucleus: The control center, containing DNA and directing cellular activities.
• Ribosomes: Sites of protein synthesis, found in all cell types.
• Endoplasmic reticulum (ER): A network of membranes involved in protein and lipid synthesis.
• Golgi apparatus: Processes, sorts, and packages proteins for secretion.
• Mitochondria: Sites of cellular respiration, producing ATP (energy).
• Chloroplasts (plant cells): Sites of photosynthesis, converting light energy into chemical energy.
• Lysosomes (animal cells): Contain enzymes that break down waste materials and cellular debris.
• Vacuoles (plant cells): Large sacs that store water, nutrients, and waste products.

Cellular Processes

• Diffusion: The movement of molecules from high to low concentration.
• Osmosis: The diffusion of water across a selectively permeable membrane.
• Active transport: The movement of molecules against their concentration gradient, requiring energy.
• Cellular respiration: A metabolic process that breaks down glucose to produce ATP.
• Photosynthesis: A metabolic process that converts light energy into chemical energy.

Cell Division and Growth

• Mitosis: A process of cell division resulting in two identical daughter cells, crucial for growth and repair.
• Meiosis: A specialized type of cell division that produces four genetically unique daughter cells, essential for sexual reproduction.
• Cell cycle: A series of events that regulate cell growth and division.

Molecular Biology

• DNA (Deoxyribonucleic acid): The genetic material containing the instructions for building and maintaining an organism.
• RNA (Ribonucleic acid): A crucial intermediary molecule that plays a role in protein synthesis and other cellular processes.
• Protein synthesis: The process of building proteins from amino acids, following the instructions encoded in DNA.
• Gene expression: The process by which information from a gene is used in the synthesis of a functional gene product.