Biology Guide PDF

Key Topics for Your Biology Exam 1. Parts of the Microscope: Body tube: A straight tube that connects the eyepiece to the objectives. Ocular (eyepiece): The lens at the top where you look through. Objective lenses: Cylindrical lenses of va...

Key Topics for Your Biology Exam 1. Parts of the Microscope: Body tube: A straight tube that connects the eyepiece to the objectives. Ocular (eyepiece): The lens at the top where you look through. Objective lenses: Cylindrical lenses of varying magnifications (e.g., 10x, 40x). Stage: A flat platform with clips to hold the sample slide. Diaphragm: A rotating disc under the stage to adjust light. Light source: A small lamp or mirror for illumination. Coarse adjustment knob: A large knob for rough focus. Fine adjustment knob: A smaller knob for precise focus. Base: A flat, sturdy bottom for stability. 2. Cell History: Robert Hooke: Discovered empty cells in cork. Matthias Schleiden: Concluded all plants are made of cells. Theodor Schwann: Proposed all animals are made of cells. Rudolph Virchow: Stated cells arise from pre-existing cells. Anton van Leeuwenhoek: Observed microorganisms. 3. Types of Cells: Animal Cell: Nucleus: Large, round structure at the center; contains DNA. Rough Endoplasmic Reticulum: Folded layers near the nucleus with tiny dots (ribosomes). Golgi Body: Stacked, flattened sacs like pancakes. Mitochondria: Oval-shaped with inner folds (cristae).  Cytoplasm: Gel-like fluid filling the cell. Lysosome: Small, round vesicles with enzymes inside. Centrioles: Cylindrical structures near the nucleus. Cell membrane: Thin, flexible outer boundary. Plant Cell: Nucleus: Large and round, often to the side; contains DNA. Chloroplast: Green ovals with stacked structures inside (thylakoids). Cell wall: Thick, rigid layer around the cell. Large vacuole: A large, clear sac in the center. Smooth Endoplasmic Reticulum: Smooth, folded layers near the nucleus. Rough Endoplasmic Reticulum: Folded layers with dots (ribosomes). Mitochondria: Oval-shaped with inner folds (cristae). Cytoplasm: Gel-like fluid filling the cell. 4. Water Properties: Cohesion: Water molecules stick to each other. Adhesion: Water sticks to other surfaces. Surface tension: Allows small organisms to walk on water. Capillarity: Water moves up thin tubes, as in plant stems. High specific heat: Water absorbs and releases heat slowly. Universal solvent: Dissolves many substances. 5. Solutions and Osmosis: Isotonic: Solute concentration is equal inside and outside the cell. Hypertonic: Higher solute concentration outside; the cell loses water. Hypotonic: Higher solute concentration inside; the cell gains water. 6. Cell Transport: Endocytosis: Large substances enter the cell (A). Exocytosis: Large substances leave the cell (D). Diffusion: Movement of molecules from high to low concentration (E). Molecular transport: Movement through proteins (B). Osmosis: Movement of water molecules (C). 7. Biomolecules: Carbohydrates: Monomers: Monosaccharides (e.g., glucose). Bio-elements: C, H, O. Bonds: Glycosidic bonds link monosaccharides. Function: Quick energy source and structural support. Lipids: Monomers: Fatty acids and glycerol. Bio-elements: C, H, O. Bonds: Ester bonds link fatty acids to glycerol. Function: Long-term energy storage, cell membranes, insulation. Proteins: Monomers: Amino acids. Bio-elements: C, H, O, N, S. Bonds: Peptide bonds link amino acids. Function: Enzymes, hormones, structural roles, and transport. Nucleic Acids: Monomers: Nucleotides (sugar, phosphate, nitrogenous base).  Bio-elements: C, H, O, N, P. Bonds: Phosphodiester bonds link nucleotides in a chain. Function: Store and transmit genetic information (DNA, RNA). 8. Important Bonds: Hydrogen bonds: Weak bonds between water molecules or DNA strands. Glycosidic bonds: Link monosaccharides in carbohydrates. Ester bonds: Connect fatty acids to glycerol in lipids. Peptide bonds: Join amino acids in proteins. Phosphodiester bonds: Connect nucleotides in nucleic acids. 9. Functional Groups: Hydroxyl (-OH): Found in alcohols and carbohydrates; makes molecules polar. Carbonyl (C=O): Found in ketones and aldehydes; makes molecules reactive. Carboxyl (-COOH): Found in amino acids and fatty acids; acidic properties. Amino (-NH2): Found in amino acids; acts as a base. Phosphate (-PO4): Found in nucleotides and phospholipids; involved in energy transfer (ATP). Sulfhydryl (-SH): Found in some amino acids; stabilizes protein structure. Benzene (C6H6): Ring structure found in aromatic compounds.