General Biology Study Guide: Key Concepts and Review Questions (Ch. 1–7)

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Biology is the scientific study of life and living organisms, encompassing their structure, function, growth, origin, evolution, and distribution.

Definition: Biology is the study of living things and their vital processes.
Scientific Method: Involves observation, hypothesis formation, experimentation, and analysis.
Qualitative vs. Quantitative Data: Qualitative data describes qualities or characteristics; quantitative data involves numerical measurements.
Controlled Experiment: An experiment in which only one variable is changed at a time.
Hypothesis vs. Theory: A hypothesis is a testable prediction; a theory is a well-substantiated explanation.
Domains of Life: Bacteria, Archaea, and Eukarya.
Levels of Biological Organization: Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere.
Emergent Properties: New properties that arise at each level of organization.
Energy Flow: Energy flows through ecosystems, while nutrients cycle.
Structure and Function: Biological structures are closely related to their functions.
Evolution: The process by which populations change over time through natural selection.
Scientific Inquiry: Involves asking questions, forming hypotheses, and testing them.

Example: The adaptation of finch beaks in the Galápagos Islands demonstrates natural selection.

All matter is composed of atoms, which combine to form elements and compounds essential for life.

Atom: The smallest unit of matter retaining the properties of an element.
Atomic Number: Number of protons in an atom.
Isotopes: Atoms of the same element with different numbers of neutrons.
Compound: Substance formed by two or more elements in fixed ratios.
Covalent Bond: Atoms share electrons.
Ionic Bond: Atoms transfer electrons.
Hydrogen Bond: Weak attraction between a hydrogen atom and another electronegative atom.
Water: Polar molecule, universal solvent, exhibits cohesion and adhesion.
pH Scale: Measures acidity or basicity; .
Buffers: Substances that minimize changes in pH.

Example: Table salt (NaCl) is formed by ionic bonding between sodium and chloride.

Cells are composed of four major types of macromolecules: carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates: Sugars and polymers; provide energy and structural support.
Lipids: Fats, oils, phospholipids, steroids; energy storage and membrane structure.
Proteins: Polymers of amino acids; perform structural, enzymatic, and regulatory functions.
Nucleic Acids: DNA and RNA; store and transmit genetic information.
Monomers and Polymers: Monomers are building blocks; polymers are chains of monomers.
Dehydration Synthesis: Forms polymers by removing water.
Hydrolysis: Breaks polymers into monomers by adding water.

Example: Glucose is a monosaccharide; starch is a polysaccharide.

Cells are the basic units of life, with structures specialized for various functions.

Prokaryotic vs. Eukaryotic Cells: Prokaryotes lack a nucleus; eukaryotes have a nucleus and organelles.
Cell Organelles: Nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes, vacuoles.
Plasma Membrane: Phospholipid bilayer with embedded proteins; regulates transport.
Cell Wall: Provides structure in plants, fungi, and some prokaryotes.
Chloroplasts: Site of photosynthesis in plants and algae.
Mitochondria: Site of cellular respiration.
Endomembrane System: Includes ER, Golgi apparatus, vesicles; involved in synthesis and transport.

Example: Animal cells have lysosomes; plant cells have chloroplasts and a cell wall.

The plasma membrane controls the movement of substances in and out of the cell, maintaining homeostasis.

Selective Permeability: Only certain molecules can pass through the membrane.
Diffusion: Movement of molecules from high to low concentration.
Osmosis: Diffusion of water across a membrane.
Active Transport: Movement against a concentration gradient using energy.
Endocytosis/Exocytosis: Bulk transport into/out of the cell.
Enzymes: Biological catalysts that speed up reactions; affected by temperature, pH, and substrate concentration.
ATP: Main energy currency of the cell.

Example: Sodium-potassium pump maintains ion gradients in animal cells.

Cells extract energy from glucose through cellular respiration, producing ATP.

Summary Equation:
Stages: Glycolysis, Krebs Cycle (Citric Acid Cycle), Electron Transport Chain.
Aerobic vs. Anaerobic Respiration: Aerobic uses oxygen; anaerobic does not.
ATP Production: Most ATP is produced in the electron transport chain.
Fermentation: Anaerobic process producing lactic acid or ethanol.

Example: Muscle cells perform lactic acid fermentation during intense exercise.

Photosynthesis converts light energy into chemical energy in plants, algae, and some bacteria.

Summary Equation:
Light Reactions: Occur in thylakoid membranes; produce ATP and NADPH.
Calvin Cycle: Occurs in stroma; uses ATP and NADPH to fix CO2 into glucose.
Chlorophyll: Main pigment absorbing light energy.
C3, C4, CAM Plants: Different adaptations for photosynthesis under various conditions.

Example: Corn is a C4 plant; cactus is a CAM plant.

These study questions cover foundational topics in general biology, including scientific inquiry, chemistry of life, cell structure, membrane function, energy transformation, and photosynthesis.
Students should be able to define key terms, explain processes, compare structures, and apply concepts to real-world examples.