# Biology Cheatsheet [[Bruce Alberts; Dennis Bray; Karen Hopkin; Alexander Johnson; Julian Lewis; Martin Raff; Keith Robert... - Essential Cell Biology]] ## Fundamental Concepts | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | Cell Theory | All living organisms are composed of cells. Cells are the basic unit of life. New cells arise from existing cells. | | Types of Cells | Prokaryotic (no nucleus, no organelles) vs. Eukaryotic (nucleus, organelles) | | Microscopy | Light microscope (cells visible) vs. Electron microscope (organelles and large molecules visible)| | Chemical Components | Atoms form molecules. Cells are primarily made of C, H, O, N. Water is a key component. | | Macromolecules | Proteins, nucleic acids (DNA/RNA), carbohydrates, lipids | ## Cell Structure and Function | Organelle | Function | |---------------------------|-------------------------------------------------------------------------------------------------| | Nucleus | Contains genetic material (DNA), controls cell activities | | Mitochondria | Powerhouse of the cell, site of ATP (energy) production | | Chloroplasts | Site of photosynthesis in plant cells | | Endoplasmic Reticulum | Rough ER (protein synthesis), Smooth ER (lipid synthesis) | | Golgi Apparatus | Modifies, sorts, and packages proteins and lipids for storage or transport | | Lysosomes | Digestive organelles, break down waste | | Peroxisomes | Breakdown of fatty acids and detoxification | | Cytoskeleton | Maintains cell shape, facilitates cell movement | ## Genetic Information and Expression | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | DNA Structure | Double helix, composed of nucleotides (A, T, C, G) | | DNA Replication | Semi-conservative process, involves DNA polymerase | | Transcription | DNA -> mRNA in the nucleus | | Translation | mRNA -> Protein in the ribosome | | Gene Regulation | Controlled by promoters, enhancers, silencers | ## Metabolism and Enzymes | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | Enzyme Function | Catalysts that speed up chemical reactions, lower activation energy | | Cellular Respiration | Glycolysis (cytoplasm), Citric Acid Cycle (mitochondria), Oxidative Phosphorylation (mitochondria) | | Photosynthesis | Light reactions (thylakoid membrane), Calvin cycle (stroma) | ## Cell Division and Genetics | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | Cell Cycle | Interphase (G1, S, G2), Mitosis (Prophase, Metaphase, Anaphase, Telophase), Cytokinesis | | Meiosis | Produces gametes, two rounds of division (Meiosis I and II), leads to genetic variation | | Mendelian Genetics | Principles of inheritance (dominant and recessive traits) | | Genetic Mutations | Changes in DNA sequence, can be beneficial, neutral, or harmful | ## Cell Communication and Signal Transduction | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | Signal Molecules | Hormones, neurotransmitters, growth factors | | Receptors | Membrane-bound (e.g., G-protein coupled receptors) or intracellular | | Signal Pathways | Cascade of events (e.g., second messengers like cAMP) leading to a cellular response | ## Evolution and Diversity | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | Natural Selection | Mechanism of evolution, survival of the fittest | | Genetic Drift | Random changes in allele frequencies in small populations | | Speciation | Formation of new and distinct species in the course of evolution | | Evolutionary Trees | Diagrams showing relationships among species based on common ancestry | ## Cellular Communities | Topic | Key Points | |---------------------------|-------------------------------------------------------------------------------------------------| | Tissues | Groups of cells with a common structure and function | | Stem Cells | Undifferentiated cells with the potential to differentiate into various cell types | | Cancer | Uncontrolled cell division, mutations in oncogenes/tumor suppressor genes | **Note:** This cheatsheet covers the main concepts and is based on the detailed content from the "Essential Cell Biology" textbook. For deeper understanding, refer to specific sections in the book . # Related - [[The Bible]] - [[Fundamental laws of biology]]