General Biology Exam 1: Comprehensive Study Guide

Chapter 1: Introduction to Biology

Definition and Scope of Biology

Biology is the scientific study of life and living organisms, encompassing various fields and subdisciplines.

• Fields and Subdisciplines: Examples include botany (study of plants), zoology (study of animals), microbiology (study of microorganisms), and ecology (study of ecosystems).

Unifying Themes of Biology

• Key Traits of Living Organisms:

  • Organization: Composed of one or more cells.

  • Metabolism: Ability to obtain and use energy.

  • Homeostasis: Regulation of internal environment.

  • Growth and Development: Increase in size and complexity.

  • Reproduction: Ability to produce offspring.

  • Response to Stimuli: React to environmental changes.

  • Evolution: Populations change over time.

• Cells: The cell is the basic unit of life. Organisms can be unicellular or multicellular.

• Viruses: Viruses are not considered living organisms because they cannot reproduce or carry out metabolism independently.

Domains and Taxonomy

• Three Domains of Life: Bacteria, Archaea, and Eukarya.

• Taxonomic Levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species (from broadest to most specific).

• Binomial Nomenclature: Scientific naming system using genus and species (e.g., Homo sapiens).

Evolution and Scientific Method

• Evolution by Natural Selection: Theory proposed by Charles Darwin explaining how species change over time due to differential survival and reproduction.

• Scientific Method: Steps include observation, hypothesis, experiment, data collection, and conclusion.

• Quantitative vs. Qualitative Data: Quantitative data is numerical; qualitative data is descriptive.

• Parts of an Experiment: Control (baseline), variables (independent and dependent).

Chapter 2: Chemistry of Life

Atoms and Elements

All matter is composed of atoms, which are the smallest units of elements.

• Periodic Table: Organizes elements by atomic number and properties.

• Atomic Structure: Protons, neutrons (nucleus), and electrons (orbitals).

• Valence Electrons: Electrons in the outermost shell; important for chemical bonding.

Chemical Bonds and Molecules

• Types of Chemical Bonds:

  • Ionic Bonds: Transfer of electrons between atoms.

  • Covalent Bonds: Sharing of electrons between atoms.

  • Hydrogen Bonds: Weak attractions between polar molecules.

• Molecules: Two or more atoms bonded together.

• Orbitals: Regions where electrons are likely to be found; shape influences chemical properties.

Chemical Reactions

• Reactants and Products: Substances that start and result from a chemical reaction.

• Conservation of Matter: Matter is not created or destroyed in chemical reactions.

• Chemical Equilibrium: State where reactants and products are balanced.

Chapter 3: Water and Life

Properties of Water

Water is essential for life due to its unique chemical and physical properties.

• Polarity: Water is a polar molecule, meaning it has partial positive and negative charges.

• Hydrophilic vs. Hydrophobic: Hydrophilic substances interact with water; hydrophobic substances do not.

• Emergent Properties: Cohesion, adhesion, high specific heat, high heat of vaporization, and solvent abilities.

pH and Buffers

• pH Scale: Measures hydrogen ion concentration.

  • Acidic: pH < 7 (high H+ concentration)

  • Basic: pH > 7 (low H+ concentration)

  • Neutral: pH = 7

• Buffers: Substances that minimize changes in pH in biological systems.

Chapter 4: Organic Molecules

Organic Molecules and Carbon

Organic molecules are carbon-based compounds essential for life.

• Valence Electrons: Carbon has four valence electrons, allowing for diverse bonding.

• Variation in Shape: Length, branching, double bonds, rings, and isomers contribute to molecular diversity.

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

  • Structural Isomers: Differ in covalent arrangement.

  • Cis-trans Isomers: Differ in spatial arrangement around double bonds.

  • Enantiomers: Mirror images due to asymmetric carbon.

Chemical Groups and Function

• Functional Groups: Groups of atoms that influence molecular properties and reactions.

  • Polar, hydrophilic, and reactive groups (e.g., hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl).

  • Methyl group is nonpolar and affects gene expression.

Chapter 5: Macromolecules and Proteins

Macromolecules, Polymers, and Monomers

Macromolecules are large, complex molecules essential for life, built from smaller units called monomers.

• Four Major Classes: Carbohydrates, lipids, proteins, and nucleic acids.

• Polymers: Long chains of monomers linked by covalent bonds.

Enzymes

• Definition: Enzymes are biological catalysts that speed up chemical reactions.

• Denaturation: Loss of enzyme structure and function due to environmental changes (e.g., temperature, pH).

Proteins and Genomics

• Proteins: Composed of 20 different amino acids; structure determines function.

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

• Genome: The complete set of genetic material in an organism.

• Genomics: Study of genomes, including gene structure, function, and mapping.

Summary Table: Major Classes of Biological Macromolecules

Class	Monomer	Function	Example
Carbohydrates	Monosaccharides	Energy storage, structural support	Glucose, cellulose
Lipids	Glycerol and fatty acids	Energy storage, membrane structure	Fats, phospholipids
Proteins	Amino acids	Catalysis, structure, transport	Enzymes, hemoglobin
Nucleic Acids	Nucleotides	Genetic information storage and transfer	DNA, RNA

Key Equations

• pH Calculation:

$\text{pH} = -\log_{10}[\text{H}^+]$

• Chemical Reaction Example:

$\text{Reactants} \rightarrow \text{Products}$

Example: The hydrolysis of ATP to ADP releases energy for cellular processes.