General Biology Exam Study Guide: Key Concepts and Topics

01 - Course Introduction

Emergent Properties and Major Themes in Biology

Biology is the study of living organisms and their interactions with the environment. Understanding its major themes and foundational concepts is essential for further study.

• Emergent Property: An emergent property is a characteristic of a system that arises from the interaction of its parts, but is not present in the individual components. Example: Life is an emergent property of complex molecular interactions within cells.

• Major Themes in Biology: Includes evolution, structure and function, information flow, energy transformations, and systems interactions.

02 - Life and Evolution

Domains of Life, Kingdoms, and Evolutionary Evidence

Biologists classify life into hierarchical categories to understand relationships and evolutionary history.

• Three Domains of Life:

  • Bacteria

  • Archaea

  • Eukarya

• Kingdoms: Within Eukarya, major kingdoms include Plantae, Animalia, Fungi, and Protista.

• Differences: Domains differ in cell structure, genetic makeup, and metabolic pathways.

• Unity and Diversity: All life shares common features (e.g., DNA), but diversity arises from evolutionary processes.

• Homology vs. Analogy: Homologous structures are inherited from a common ancestor; analogous structures arise independently due to similar selective pressures.

• Evidence for Evolution: Fossil records, comparative anatomy, molecular biology, and biogeography support evolutionary theory.

• Descent with Modification: Species change over time, giving rise to new species.

03 - Natural Selection

Mechanisms and Outcomes of Natural Selection

Natural selection is the process by which organisms better adapted to their environment tend to survive and reproduce.

• Charles Darwin: Proposed natural selection as the mechanism for evolution.

• Adaptation: Traits that improve survival and reproduction become more common in populations.

• Artificial Selection: Humans select for desirable traits in organisms, demonstrating the principles of selection.

• Situations for Natural Selection: Environmental changes, competition, and predation can drive selection.

04 - Support for Evolution

Evidence and Concepts Supporting Evolution

Multiple lines of evidence support the theory of evolution and help explain how species change over time.

• Directly Observed Evolutionary Change: Examples include antibiotic resistance in bacteria and changes in beak size in finches.

• Homology: Similar structures in different species due to shared ancestry.

• Fossil Record: Shows transitional forms and chronological changes in species.

• Biogeography: Study of the geographic distribution of species; supports patterns of evolution.

05 - Phylogeny

Phylogenetic Trees and Classification

Phylogeny is the study of evolutionary relationships among organisms, often represented as trees.

• Phylogeny: The evolutionary history and relationships among species.

• Phylogenetic Tree: Diagram showing evolutionary relationships; branches represent lineages.

• Nodes: Points where lineages diverge; represent common ancestors.

• Clade: A group consisting of an ancestor and all its descendants.

• Linnaean Hierarchical Classification:

  • Domain

  • Kingdom

  • Phylum

  • Class

  • Order

  • Family

  • Genus

  • Species

06 - Chemical Bonds

Atoms, Elements, and Types of Chemical Bonds

Chemical bonds are forces that hold atoms together in molecules and compounds, essential for biological structure and function.

• Atom: Basic unit of matter, composed of protons, neutrons, and electrons.

• Element: Substance consisting of one type of atom.

• Trace Elements: Elements required in small amounts for life (e.g., iron, iodine).

• Chemical Bond: Attractive force holding atoms together. Types:

  • Covalent Bonds: Atoms share electrons.

  • Ionic Bonds: Atoms transfer electrons, forming charged ions.

• Polar Covalent Bonds: Electrons are shared unequally, creating partial charges.

• Electronegativity: Measure of an atom's ability to attract electrons.

• Hydrogen Bonding: Weak attraction between a hydrogen atom and an electronegative atom (e.g., oxygen, nitrogen).

• Water as a Polar Molecule: Water's polarity allows it to form hydrogen bonds, making it an excellent solvent.

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

07/08 - Organic Compounds

Carbon Chemistry and Biological Macromolecules

Organic molecules are carbon-based compounds essential for life, including carbohydrates, lipids, proteins, and nucleic acids.

• Organic Molecule: Compound containing carbon atoms bonded to hydrogen and other elements.

• Carbon's Special Properties: Forms four covalent bonds, allowing for diverse structures.

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

• Functional Groups: Specific groups of atoms that confer particular properties (e.g., hydroxyl, carboxyl, amino).

• Macromolecules: Large molecules formed by polymerization of monomers. Types:

  • Carbohydrates

  • Lipids

  • Proteins

  • Nucleic Acids

• Polymerization: Process of joining monomers to form polymers.

• Carbohydrates: Provide energy and structural support. Monomers: Monosaccharides.

• Lipids: Include fats, oils, and steroids; used for energy storage and membrane structure.

• Proteins: Made of amino acids; perform structural, enzymatic, and regulatory functions.

• Protein Structure:

  • Primary: Sequence of amino acids.

  • Secondary: Alpha helices and beta sheets.

  • Tertiary: 3D folding.

  • Quaternary: Multiple polypeptides.

• Denaturation: Loss of protein structure due to environmental changes.

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

• Nucleotide: Monomer of nucleic acids; consists of a sugar, phosphate, and nitrogenous base.

• DNA vs. RNA: DNA is double-stranded, RNA is single-stranded; they differ in sugar and bases.

• Base-Pairing Rules: In DNA, adenine pairs with thymine, cytosine pairs with guanine.

Additional Info

• Equation Example: The general formula for photosynthesis is: $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$

• Classification Table:

  Level	Example
  Domain	Eukarya
  Kingdom	Animalia
  Phylum	Chordata
  Class	Mammalia
  Order	Primates
  Family	Hominidae
  Genus	Homo
  Species	Homo sapiens