Bio 1 test in depth notes

CHAPTER 1: INTRODUCTION TO LIFE
1. What Is Biology and Characteristics of Life

  • Biology: The study of life.

  • Characteristics of Living Organisms:

    • Complex & Ordered: Carbon-based structures organized into hierarchical levels.

    • Cellular Basis: Composed of one or more cells.

    • Genetics & Reproduction: Possess DNA directing cellular processes and pass traits to offspring (e.g., binary fission).

    • Energy & Homeostasis: Utilize energy to power life processes and regulate stable internal conditions.

    • Growth & Response: Grow, develop, and respond to environmental stimuli.

    • Evolutionary Adaptation: Populations adapt over generations through natural selection.

2. Experimental Design

  • Steps: Define research question →\rightarrow background research →\rightarrow hypothesis →\rightarrow identify variables (independent, dependent, controlled) →\rightarrow establish experimental and control groups →\rightarrow collect/analyze data with statistics →\rightarrow draw conclusions, report, and refine.

CHAPTER 2: CHEMISTRY — WATER
1. Atomic Structure and Chemical Bonds

  • Atoms & Periodic Table: Organized by periods and valence-electron columns.

  • Isotopes: Differing neutron numbers; radioactive isotopes decay with known half-lives used in fossil dating.

  • Chemical Bonds:

    • Ionic: Electrostatic attraction between cations (electron donors) and anions (electron acceptors).

    • Covalent: Sharing of electron pairs equally (nonpolar) or unequally (polar).

2. Emergent Properties of Water

  • Structure & Abundance: Polar H2OH_2O molecules form hydrogen bonds. Covers 34\frac{3}{4} of Earth; organisms are 70–95%70\text{--}95\% water.

  • Cohesion & Adhesion: Cohesion creates surface tension; adhesion allows water to cling to polar surfaces, aiding xylem transport via transpiration.

  • Thermal Stability:

    • High Specific Heat: Resists temperature shifts, buffering environmental and cellular temperatures.

    • High Heat of Vaporization: Enables evaporative cooling (sweating, panting, transpiration).

  • Density: Maximum density at 4 ∘C4\,^\circ\text{C}; ice (0 ∘C0\,^\circ\text{C}) floats, insulating aquatic life.

  • Solvent Characteristics: Dissolves polar and ionic substances (hydrophilic); excludes nonpolar substances (hydrophobic).

3. pH and Buffers

  • Dissociation: H2O⇌H++OH−H_2O \rightleftharpoons H^+ + OH^-

  • Acids & Bases: Acids increase H+H^+ (pH<7\text{pH} < 7); bases decrease H+H^+ (pH>7\text{pH} > 7). Blood pH is regulated at pH 7.35–7.45\text{pH } 7.35\text{--}7.45.

  • Buffers: Donate or accept H+H^+ to prevent sudden pH shifts caused by metabolic acids.

CHAPTER 3: THE MOLECULES OF LIFE
1. Carbon and Functional Groups

  • Carbon Diversity: Contains 44 valence electrons, forming varied carbon skeletons (chains, branches, rings).

  • Functional Groups: Alter reactivity (Hydroxyl: −OH-\text{OH}; Carboxyl: −COOH-\text{COOH}; Amino: −NH2-\text{NH}_2; Phosphate: −PO4-\text{PO}_4).

2. Macromolecules

  • Reactions: Dehydration reactions join monomers by removing water; hydrolysis breaks polymers by adding water.

  • Carbohydrates:

    • Monosaccharides: Fuel units such as glucose, galactose, and fructose; pentoses (55 carbons) and hexoses (66 carbons).

    • Disaccharides: Two sugars linked (maltose, sucrose, lactose).

    • Polysaccharides: Energy storage (starch in plants, glycogen in animals) or structural support (cellulose in plant cell walls, chitin in fungi/arthropods).

  • Lipids:

    • Fats: 11 glycerol + 33 fatty acids; yield twice the energy of carbohydrates per gram. Saturated fats have single bonds (solid); unsaturated fats have double bonds (liquid).

    • Phospholipids: Amphipathic molecules forming cell membrane bilayers.

    • Steroids: Four fused rings (e.g., cholesterol, steroid hormones).

  • Proteins: Chains of 2020 amino acids linked by peptide bonds. Primary sequence dictates structure; denaturation (unfolding) occurs via heat, pH shifts, or chemicals.

  • Nucleic Acids: DNA and RNA polymers built from nucleotides (pentose sugar, phosphate, nitrogenous base) storing and expressing genetic information.

CHAPTER 4: A TOUR OF THE CELL
1. Fundamentals of Cells

  • Cell Theory: All organisms are made of cells, the cell is the basic functional unit, and cells come from pre-existing cells.

  • Surface Area-to-Volume Ratio: Small cell size optimizes resource intake, waste removal, and heat release.

2. Cellular Organization

  • Prokaryotes: Lack a nucleus; DNA resides in a nucleoid. Possess ribosomes, plasma membrane, cell wall, and optional capsules/flagella.

  • Eukaryotes: Contain a membrane-enclosed nucleus and specialized organelles.

    • Plant-Specific: Cell wall, chloroplasts, central vacuole, plasmodesmata.

    • Animal-Specific: Lysosomes, centrioles, microvilli.

3. Key Organelles

  • Nucleus: Stores DNA; synthesizes rRNA and exports mRNA.

  • Ribosomes: Non-membranous structures that assemble proteins (free in cytosol or bound to ER).

  • Endomembrane System:

    • Rough ER: Synthesizes secretory and membrane proteins.

    • Smooth ER: Synthesizes lipids and detoxifies poisons/drugs.

    • Golgi Apparatus: Modifies, sorts, and packages cellular products.

    • Lysosomes & Vacuoles: Hydrolytic breakdown (lysosomes) and storage/water regulation (vacuoles).

  • Energy Transducers:

    • Mitochondria: Site of cellular respiration.

    • Chloroplasts: Site of photosynthesis (Sunlight+H2O+CO2→C6H12O6+O2+H2O\text{Sunlight} + H_2O + CO_2 \rightarrow C_6H_{12}O_6 + O_2 + H_2O).

  • Cytoskeleton: Microtubules (tubulin) and microfilaments (actin) maintain structure and facilitate motility via cilia/flagella.