Overview

This topic explores the organization and function of cells, how they divide, and how genetic information is stored, transmitted, and expressed. Understanding these processes is essential for studying all biological systems, from simple bacteria to complex organisms.

Key Concepts and Structures

• Cell Theory: States that all living organisms are made of cells, cells are the basic unit of life, and all cells come from pre-existing cells.
• Prokaryotic vs. Eukaryotic Cells: Prokaryotes (bacteria) lack a nucleus and organelles; eukaryotes (plants, animals) have membrane-bound organelles and a defined nucleus.
• Organelles: Key cell structures include the nucleus (stores DNA), mitochondria (powerhouse), ribosomes (protein synthesis), endoplasmic reticulum, Golgi apparatus, lysosomes, and chloroplasts (in plants).
• Cell Membrane: A phospholipid bilayer that controls movement of substances in and out of the cell; maintains homeostasis.
• Mitosis: A type of cell division that results in two genetically identical daughter cells; used in growth and repair.
• Meiosis: Division that produces four genetically diverse gametes (sperm/egg); involves two rounds of division and contributes to genetic variation.
• DNA: Deoxyribonucleic acid stores genetic information in a double helix structure made of nucleotides (A, T, C, G).
• Genes and Chromosomes: Genes are segments of DNA that code for proteins; chromosomes are long DNA molecules organized into units within the nucleus.
• Genotype and Phenotype: Genotype is an organism's genetic makeup; phenotype is the observable traits resulting from that genotype.
• Mendelian Genetics: Gregor Mendel discovered inheritance patterns through dominant and recessive alleles. Includes concepts like homozygous, heterozygous, and Punnett squares.

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