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General Biology Key Concepts

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  • Proximate vs. Ultimate Explanations

    Proximate explanations address immediate mechanisms (e.g., how cells divide). Ultimate explanations address evolutionary reasons (e.g., why cell division is advantageous).

  • Key Features of Experimental Design

    Includes control groups, independent and dependent variables, replication, and randomization to ensure valid results.

  • Atomic Structure

    Atoms consist of a nucleus with protons and neutrons, surrounded by electron shells.

  • Types of Chemical Bonds

    Ionic bonds, covalent bonds, and hydrogen bonds form based on electronegativity differences.

  • Properties of Water

    Water has covalent bonds within molecules and hydrogen bonds between molecules, leading to high specific heat, cohesion, and adhesion.

  • pH and Acids/Bases

    Acids donate H+ ions; bases accept H+ ions. pH measures hydrogen ion concentration and changes logarithmically with [H+].

  • Functional Groups in Organic Molecules

    Examples: Amino (-NH2), Carboxyl (-COOH), Hydroxyl (-OH), Methyl (-CH3), Phosphate (-PO4), Sulfhydryl (-SH).

  • First and Second Laws of Thermodynamics

    First Law: Energy cannot be created or destroyed. Second Law: Entropy increases in spontaneous processes.

  • Gibbs Free Energy and Reaction Spontaneity

    Gibbs free energy (\(\Delta G\)) determines if a reaction is spontaneous (<0) or not (>0).

  • Biological Macromolecules and Their Monomers

    Proteins (amino acids), nucleic acids (nucleotides), carbohydrates (monosaccharides), lipids (fatty acids and glycerol).

  • Levels of Protein Structure

    Primary: amino acid sequence; Secondary: alpha helices and beta sheets; Tertiary: 3D folding; Quaternary: multiple polypeptides.

  • Nucleic Acid Types and Functions

    DNA stores genetic info; RNA (mRNA, tRNA, rRNA) involved in protein synthesis and regulation.

  • Carbohydrate Types and Functions

    Monosaccharides (glucose), disaccharides (sucrose), polysaccharides (starch, cellulose); energy storage and structure.

  • Lipid Categories and Roles

    Phospholipids form membranes; fats store energy; steroids act as signaling molecules.

  • Phospholipid Bilayer Formation

    Phospholipids form bilayers with hydrophilic heads facing water and hydrophobic tails inward.

  • Membrane Transport Mechanisms

    Diffusion, osmosis, facilitated diffusion (passive); active transport requires energy; includes channels, carriers, and pumps.

  • Stages of Cellular Respiration

    Glycolysis, pyruvate processing, citric acid cycle, electron transport chain and oxidative phosphorylation.

  • Fermentation Types and ATP Yield

    Lactic acid fermentation (animals), ethanol fermentation (yeast); produce less ATP than aerobic respiration.

  • Photosynthesis Overview

    Converts CO2 and H2O into glucose and O2 using light energy; includes light reactions and Calvin cycle.

  • Differences Between Prokaryotic and Eukaryotic Cells

    Prokaryotes lack membrane-bound organelles; eukaryotes have nucleus and organelles like mitochondria.

  • Phases of Mitosis

    Prophase, metaphase, anaphase, telophase; followed by cytokinesis.

  • DNA Replication Process

    Involves helicase, primase, DNA polymerases, ligase; leading strand synthesized continuously, lagging strand discontinuously.

  • Gene Expression: Transcription and Translation

    Transcription produces mRNA from DNA; translation synthesizes proteins from mRNA codons using ribosomes and tRNA.

  • Regulation of Gene Expression in Prokaryotes

    Operons control gene clusters; lac operon is inducible, trp operon is repressible; regulation via repressors and activators.

  • Regulation of Gene Expression in Eukaryotes

    Includes chromatin modification, transcription factors, mRNA processing, and RNA interference.

  • Meiosis vs. Mitosis

    Mitosis produces two identical diploid cells; meiosis produces four genetically unique haploid cells.

  • Mendel’s Laws of Inheritance

    Law of Segregation: alleles separate during gamete formation; Law of Independent Assortment: genes assort independently.

  • Mechanisms of Evolution

    Mutation, gene flow, genetic drift, and natural selection change allele frequencies in populations.

  • Hardy-Weinberg Equilibrium

    Population allele frequencies remain constant if no evolution occurs; described by \(p^2 + 2pq + q^2 = 1\).

  • Types of Natural Selection

    Stabilizing (favors average), directional (favors one extreme), disruptive (favors both extremes).