Biology Study Library.

Elements essential for carbon-based life · Properties of water: cohesion, adhesion, specific heat, polarity, hydrogen bonding · Biological macromolecules: carbohydrates, lipids, proteins, nucleic acids — structure and function · Enzyme structure: active site, substrate specificity, activation energy · Factors affecting enzyme activity: temperature, pH, substrate concentration, inhibitors · Free energy and thermodynamics: Gibbs free energy (ΔG), endergonic vs. exergonic reactions · ATP as biological energy currency

Prokaryotic vs. eukaryotic cell structure and compartmentalization · Cell membrane: fluid mosaic model, phospholipid bilayer, membrane proteins · Passive transport: simple diffusion, facilitated diffusion, osmosis · Active transport: pumps, endocytosis, exocytosis · Organelle structure-function relationships: mitochondria, chloroplast, endoplasmic reticulum, Golgi apparatus, ribosomes, nucleus, vacuoles, lysosomes · Cell size constraints: surface area-to-volume ratio · Endomembrane system and vesicle trafficking

Photosynthesis: light-dependent reactions — photosystems I and II, electron transport chain, ATP synthase, NADPH production · Photosynthesis: Calvin cycle (light-independent reactions) — carbon fixation, G3P production, RuBisCO · Cellular respiration: glycolysis — location (cytoplasm), inputs/outputs, net ATP yield · Cellular respiration: pyruvate oxidation and Krebs cycle — acetyl-CoA entry, CO2 release, NADH/FADH2 production · Cellular respiration: oxidative phosphorylation — electron transport chain, chemiosmosis, ATP synthase · ATP yield comparison across aerobic respiration stages · Anaerobic pathways: lactic acid fermentation, alcoholic fermentation · Factors affecting rates of photosynthesis and cellular respiration

Signal transduction pathway stages: reception, transduction, response · Ligand-receptor specificity and signal amplification via second messengers · Types of cell signaling: endocrine (long-distance), paracrine, autocrine, direct contact (juxtacrine) · Cell cycle stages: interphase (G1, S, G2) and mitotic phase (mitosis + cytokinesis) · Mitosis stages: prophase, metaphase, anaphase, telophase (PMAT) · Cell cycle checkpoints: G1, G2, and spindle assembly checkpoints · Proto-oncogenes, tumor suppressor genes, and cancer as uncontrolled cell division · Apoptosis and its role in development and disease prevention

Meiosis I and II: stages, chromosome behavior, comparison with mitosis · Sources of genetic variation: crossing over (recombination), independent assortment, random fertilization · Mendelian genetics: law of segregation, law of independent assortment · Monohybrid and dihybrid crosses using Punnett squares · Dominant, recessive, and codominant alleles; incomplete dominance · Sex-linked (X-linked) inheritance patterns · Polygenic traits and continuous variation · Chi-square (χ²) statistical test for goodness-of-fit in genetics problems

DNA structure: double helix, antiparallel strands, complementary base pairing · DNA replication: semiconservative model, leading and lagging strand synthesis, key enzymes (helicase, primase, DNA polymerase, ligase) · Transcription: RNA polymerase, promoter recognition, mRNA synthesis, termination · Translation: ribosome structure, tRNA-codon matching, polypeptide elongation and termination · Gene regulation in prokaryotes: lac operon model (inducible), trp operon (repressible) · Gene regulation in eukaryotes: transcription factors, enhancers, silencers, chromatin remodeling · Post-transcriptional regulation: 5' cap and poly-A tail, splicing (introns/exons), miRNA, siRNA · Epigenetic mechanisms: DNA methylation and histone acetylation/methylation effects on gene expression · Biotechnology applications: PCR, gel electrophoresis, CRISPR-Cas9, bacterial transformation, recombinant DNA technology

Evidence for evolution: fossil record, comparative anatomy (homologous, analogous, vestigial structures), molecular homology, biogeography · Mechanisms of natural selection: heritable variation, differential reproductive success, adaptation · Types of natural selection: directional, stabilizing, disruptive (diversifying) · Other evolutionary mechanisms: genetic drift (bottleneck and founder effects), gene flow, mutation · Hardy-Weinberg equilibrium: conditions (large population, random mating, no mutation/migration/selection) and allele/genotype frequency calculations · Hardy-Weinberg as a null model — deviation from equilibrium indicates evolution · Speciation: allopatric vs. sympatric speciation; pre- and post-zygotic reproductive isolation mechanisms · Phylogenetics: constructing and interpreting cladograms, parsimony principle, shared derived characters (synapomorphies) · Molecular clocks and evidence from DNA/protein sequence comparisons

Community ecology: species interactions — predation, interspecific competition, mutualism, commensalism, parasitism · Population ecology: exponential growth model (dN/dt = r_max N), logistic growth model (dN/dt = r_max N × (K−N)/K), carrying capacity (K) · Limiting factors: density-dependent vs. density-independent · Energy flow through ecosystems: trophic levels, food webs, ~10% energy transfer efficiency rule · Primary productivity: gross primary productivity (GPP) vs. net primary productivity (NPP) · Biogeochemical cycles: carbon cycle, nitrogen cycle (fixation, nitrification, denitrification), phosphorus cycle, water cycle · Ecosystem stability: keystone species, biodiversity, ecological succession (primary and secondary) · Human impacts: habitat fragmentation, climate change effects, invasive species, conservation biology