General Biology: Core Themes and Concepts (Ch. 1–5) Study Guide

Themes of Biology and the Scientific Method (Ch. 1)

Properties of Life and Biological Organization

Biology is the study of living organisms and their interactions with the environment. Understanding the properties that distinguish living from nonliving things is fundamental to biology.

• Properties of Life: Order, regulation, energy processing, growth and development, reproduction, response to the environment, and evolutionary adaptation.

• Levels of Biological Organization: Molecule, organelle, cell, tissue, organ, organ system, organism, population, community, ecosystem, biosphere.

• Example: A cell is the basic unit of life, while an ecosystem includes all living and nonliving components in a particular area.

Scientific Inquiry and Experimental Design

The scientific method is a systematic approach to understanding the natural world through observation and experimentation.

• Steps in Scientific Method: Observation, question, hypothesis, prediction, experiment, analysis, and conclusion.

• Hypothesis: A testable explanation for an observation.

• Prediction: A logical statement about what will happen if the hypothesis is correct.

• Variables: Independent variable is manipulated; dependent variable is measured.

• Control Group: Used for comparison to ensure experimental validity.

• Graphical Representation: Data is often displayed in graphs for analysis.

Logical Arguments and Scientific Terms

• Fact: An observation that has been repeatedly confirmed.

• Theory: A broad explanation supported by a large body of evidence.

• Law: A statement describing consistent natural phenomena.

• Opinion: A personal belief not necessarily based on evidence.

The Chemical Context of Life (Ch. 2)

Atoms, Elements, and Chemical Bonds

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

• Atoms: Consist of protons, neutrons, and electrons.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Ions: Atoms or molecules with a net electric charge due to loss or gain of electrons.

• Chemical Bonds: Covalent (sharing electrons), ionic (transfer of electrons), hydrogen bonds (attraction between polar molecules).

• Oxidation and Reduction: Oxidation is loss of electrons; reduction is gain of electrons.

Energy in Chemical Reactions

• Exergonic Reaction: Releases energy.

• Endergonic Reaction: Requires energy input.

• Enzymes: Biological catalysts that lower activation energy.

• Catabolism vs. Anabolism: Catabolism breaks down molecules; anabolism builds molecules.

• Gibbs Free Energy Equation:

$\Delta G = \Delta H - T\Delta S$

• ΔG: Change in free energy; ΔH: Change in enthalpy; T: Temperature (Kelvin); ΔS: Change in entropy.

Water and Life (Ch. 3)

Properties of Water

Water's unique properties make it essential for life.

• Polarity: Water is a polar molecule, leading to hydrogen bonding.

• Cohesion and Adhesion: Cohesion is attraction between water molecules; adhesion is attraction to other substances.

• High Specific Heat: Water resists temperature change.

• Solvent Properties: Water dissolves many substances due to its polarity.

• Hydrophilic vs. Hydrophobic: Hydrophilic substances dissolve in water; hydrophobic do not.

Acids, Bases, and pH

• pH Scale: Measures hydrogen ion concentration; ranges from 0 (acidic) to 14 (basic).

• Buffers: Substances that minimize changes in pH.

Carbon and the Molecular Diversity of Life (Ch. 4)

Carbon Compounds and Functional Groups

Carbon's ability to form four covalent bonds makes it the backbone of biological molecules.

• Organic Molecules: Contain carbon and hydrogen; may include other elements.

• Functional Groups: Groups of atoms that confer specific properties (e.g., hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate).

• Isomers: Molecules with the same formula but different structures.

The Structure and Function of Large Biological Molecules (Ch. 5)

Macromolecules: Carbohydrates, Lipids, Proteins, Nucleic Acids

Large biological molecules are essential for structure and function in living organisms.

• Carbohydrates: Sugars and polymers of sugars; provide energy and structural support.

• Lipids: Fats, phospholipids, steroids; energy storage, membrane structure, signaling.

• Proteins: Polymers of amino acids; perform a wide range of functions including catalysis, transport, and structure.

• Nucleic Acids: DNA and RNA; store and transmit genetic information.

Structure and Synthesis of Macromolecules

• Monomers and Polymers: Monomers are building blocks; polymers are long chains of monomers.

• Dehydration Synthesis: Joins monomers by removing water.

• Hydrolysis: Breaks polymers into monomers by adding water.

• Levels of Protein Structure: Primary, secondary, tertiary, quaternary.

• DNA Structure: Double helix with complementary base pairing.

Biological Functions and Nutrition

• ATP/ADP Cycle: ATP stores and releases energy for cellular processes.

• Diet and Health: Essential macromolecules, vitamins, minerals, and healthy dietary choices (e.g., omega fats, fiber, glycemic index).

• Food Labels: Understanding nutritional information for healthy diet planning.

Macromolecule	Monomer	Main Function
Carbohydrate	Monosaccharide	Energy, structure
Lipid	Fatty acid, glycerol	Energy storage, membranes
Protein	Amino acid	Catalysis, structure, transport
Nucleic Acid	Nucleotide	Genetic information

Additional info: These notes expand on the provided outline by adding definitions, examples, and context for each major topic, ensuring a comprehensive review for exam preparation.