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

• Subfields: Genetics, physiology, evolutionary biology, etc.

Key Traits of Living Organisms

Living organisms share several defining characteristics.

• Key Traits: Organization, metabolism, homeostasis, growth, reproduction, response to stimuli, and adaptation.

• Examples: Plants grow and reproduce; animals respond to their environment.

• Cell Theory: Every organism consists of one or more cells.

Domains and Taxonomy

Biological classification organizes life into hierarchical categories.

• Three Domains: Bacteria, Archaea, 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 Natural Selection

Evolution explains the diversity of life through gradual changes over time.

• Darwin's Observations: Variation exists in populations; more offspring are produced than can survive; traits are inherited.

• Natural Selection: Individuals with advantageous traits survive and reproduce.

Scientific Method and Experimentation

Scientific inquiry relies on systematic observation and experimentation.

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

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

Chapter 2: Chemistry of Life

Atoms and Elements

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

• Atomic Structure: Protons, neutrons, electrons.

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

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

Chemical Bonds and Molecules

Atoms interact to form molecules through various types of chemical bonds.

• Ionic Bonds: Transfer of electrons between atoms.

• Covalent Bonds: Sharing of electrons.

• Polar vs. Nonpolar Molecules: Polar molecules have unequal electron sharing; nonpolar have equal sharing.

• Orbitals: Regions where electrons are likely to be found; shape affects bonding.

Chemical Reactions

Chemical reactions involve the rearrangement of atoms to form new substances.

• Reactants and Products: Substances entering and resulting from a reaction.

• Conservation of Matter: Matter is not created or destroyed.

• Chemical Equilibrium: Reversible reactions reach a state where reactant and product concentrations remain constant.

Chapter 3: Water and Its Properties

Polarity and Hydrogen Bonding

Water is a polar molecule, which gives it unique properties essential for life.

• Polarity: Unequal sharing of electrons creates partial charges.

• Hydrogen Bonds: Weak attractions between water molecules.

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

Emergent Properties of Water

Water exhibits several emergent properties due to its molecular structure.

• Cohesion: Water molecules stick together.

• Adhesion: Water molecules stick to other surfaces.

• High Specific Heat: Water resists temperature changes.

• Solvent Abilities: Water dissolves many substances.

pH and Buffers

pH measures the concentration of hydrogen ions in a solution.

• pH Scale: Ranges from 0 (acidic) to 14 (basic); 7 is neutral.

• Acids: Low pH, high hydrogen ion concentration.

• Bases: High pH, low hydrogen ion concentration.

• Buffers: Substances that stabilize pH in biological systems.

Chapter 4: Organic Molecules

Organic Molecules and Carbon

Organic molecules are based on carbon and form the foundation of biological macromolecules.

• Carbon's Importance: Forms four covalent bonds; allows for complex structures.

• Variation in Shape: Length, branching, rings, and isomers.

• Isomers: Molecules with the same formula but different structures (structural, cis-trans, enantiomers).

Chemical Groups and Function

Chemical groups attached to carbon skeletons influence molecular properties and functions.

• Polar Interactions: Affect solubility and reactivity.

• Methyl Group: Nonpolar; affects gene expression and molecular identity.

• Functional Groups: Hydroxyl, carboxyl, amino, phosphate, etc.

Chapter 5: Macromolecules and Proteins

Macromolecules, Polymers, and Monomers

Biological macromolecules are large molecules composed of repeating subunits.

• Types: Carbohydrates, lipids, proteins, nucleic acids.

• Monomers: Simple subunits (e.g., amino acids, nucleotides).

• Polymers: Chains of monomers (e.g., proteins, DNA).

Enzymes

Enzymes are biological catalysts that speed up chemical reactions.

• Structure: Usually proteins.

• Function: Lower activation energy, increase reaction rate.

• Denaturation: Loss of structure and function due to environmental changes.

Proteins and Genomics

Proteins are diverse macromolecules with various functions; genomics studies their genetic basis.

• Amino Acids: 20 types; asymmetric carbon.

• Protein Structure: Four levels (primary, secondary, tertiary, quaternary).

• Genome: Complete set of genetic material; genomics studies gene function and expression.

Key Table: Types of Chemical Bonds

Bond Type	Description	Example
Ionic	Transfer of electrons between atoms	NaCl (sodium chloride)
Covalent	Sharing of electrons between atoms	H2O (water)
Hydrogen	Weak attraction between polar molecules	Between water molecules
Van der Waals	Weak, transient interactions	Between nonpolar molecules

Key Equations

• Chemical Reaction: $\text{Reactants} \rightarrow \text{Products}$

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