Biology Study Guide PDF

1. Cell Structure and Function: Prokaryotic vs. Eukaryotic cells: Prokaryotes lack a nucleus and membrane- bound organelles, while eukaryotes have these structures. Organelles and their roles: Nucleus: Contains genetic material. Mitochondria: Powerhouse of the cell (ATP production). Ribo...

1. Cell Structure and Function: Prokaryotic vs. Eukaryotic cells: Prokaryotes lack a nucleus and membrane- bound organelles, while eukaryotes have these structures. Organelles and their roles: Nucleus: Contains genetic material. Mitochondria: Powerhouse of the cell (ATP production). Ribosomes: Protein synthesis. Endoplasmic Reticulum (ER): Rough ER synthesizes proteins; Smooth ER synthesizes lipids. Golgi Apparatus: Modifies, sorts, and packages proteins. 2. Cell Membrane and Transport: Structure: Phospholipid bilayer with embedded proteins. Transport Mechanisms: Passive transport (diffusion, osmosis, facilitated diffusion). Active transport (requires ATP). Endocytosis and exocytosis. 3. Cellular Respiration: Overview of ATP production: Glycolysis: Breaks down glucose into pyruvate. Krebs Cycle: Produces electron carriers. Electron Transport Chain: Uses oxygen to produce ATP. Aerobic vs. anaerobic respiration (fermentation). 4. Photosynthesis: Light-dependent reactions occur in the thylakoids and produce ATP and NADPH. Calvin Cycle occurs in the stroma and converts CO2 into glucose. 5. Enzymes: Biological catalysts that speed up reactions by lowering activation energy. Factors affecting enzyme activity: temperature, pH, and substrate concentration. 1. DNA Structure and Function Double helix structure with nucleotides (A, T, G, C). Replication is semi- conservative: Each new DNA molecule has one old strand and one new strand. 2. RNA and Protein Synthesis: Transcription: DNA is transcribed into mRNA in the nucleus. Translation: mRNA is translated into proteins by ribosomes in the cytoplasm. 3. Mendelian Genetics: Laws of inheritance: Law of Segregation: Alleles separate during gamete formation. Law of Independent Assortment: Genes for different traits assort independently. Dominant and recessive traits; Punnett squares for predicting offspring genotypes. 4. Non-Mendelian Genetics: Incomplete dominance: Blended traits (e.g., red + white = pink). Codominance: Both traits are expressed (e.g., AB blood type). Polygenic traits: Controlled by multiple genes (e.g., height, skin color). 5. Mutations: Types: Point mutations, frameshift mutations. Effects: Beneficial, neutral, or harmful. 6. Biotechnology: Techniques: Gel electrophoresis, CRISPR, and genetic engineering. Applications: Medicine, agriculture, and forensics. 1. Levels of Organization: Organism, population, community, ecosystem, biome, and biosphere. 2. Energy Flow: Producers (autotrophs), consumers (heterotrophs), decomposers. Food chains and food webs: Arrows represent energy flow. Trophic levels and the 10% rule: Only 10% of energy is transferred between levels. 3. Biogeochemical Cycles: Water cycle: Evaporation, condensation, precipitation, runoff. Carbon cycle: Photosynthesis and cellular respiration balance CO2. Nitrogen cycle: Nitrogen fixation, nitrification, denitrification. 4. Ecosystem Dynamics: Biotic and abiotic factors. Habitat vs. niche. Succession: Primary (no soil) vs. secondary (soil present). 5. Population Ecology: Population growth models: Exponential growth: J-shaped curve. Logistic growth: S- shaped curve with carrying capacity. Factors: Birth rate, death rate, immigration, emigration. 6. Human Impact: Pollution, deforestation, climate change. Conservation efforts and sustainable practices. 1. Natural Selection: Definition: Process where organisms better adapted to their environment survive and reproduce. Principles: Overproduction of offspring. Genetic variation. Struggle for existence (competition). Differential survival and reproduction (adaptations). Evidence of Evolution: Fossils: Show gradual changes over time. Comparative anatomy: Homologous structures: Similar structure, different function.  Analogous structures: Different structure, similar function. Vestigial structures: Reduced/unused structures from ancestors. Embryology: Similarities in early development suggest common ancestry. Molecular evidence: DNA and protein comparisons. 2. Mechanisms of Evolution: Genetic drift: Random changes in allele frequency (bottleneck and founder effects). Gene flow: Movement of alleles between populations. Mutations: Source of new genetic variation. Sexual selection: Traits that improve mating success. 3. Speciation: Formation of new species from existing ones. Mechanisms: Geographic isolation: Physical barriers. Reproductive isolation: Prezygotic and postzygotic barriers. Patterns: Gradualism: Slow, steady change. Punctuated equilibrium: Rapid changes followed by stability. 4. Human Evolution: Common ancestors with primates. Fossil evidence of bipedalism and increasing brain size. 5. Misconceptions: Evolution does not happen within an individual’s lifetime. It is not goal-directed; traits do not arise out of need.