Biology Exam 1 Study Guide: Foundations, Chemistry, Water, Carbon, and Macromolecules

Chapter 1: Evolution, the Themes of Biology, and Scientific Inquiry

Characteristics of Living Things

• Order: Living things exhibit complex but ordered organization.

• Regulation (Homeostasis): Organisms maintain a stable internal environment.

• Growth and Development: Organisms grow and develop according to inherited instructions.

• Energy Processing: Living things acquire and use energy for metabolic processes.

• Response to Environment: Organisms respond to environmental stimuli.

• Reproduction: Organisms reproduce their own kind.

• Evolutionary Adaptation: Populations evolve over generations through adaptations.

Scientific Inquiry (Scientific Method)

• Observation: Gathering information about phenomena.

• Question: Formulating a question based on observations.

• Hypothesis: A testable, falsifiable statement that explains observations.

• Prediction: Logical outcomes expected if the hypothesis is correct.

• Experiment: Testing the hypothesis under controlled conditions.

• Analysis: Interpreting data to draw conclusions.

• Conclusion: Accepting, rejecting, or revising the hypothesis.

• Good Hypothesis: Must be testable and falsifiable. Example: "If plants are given fertilizer, then they will grow taller than plants not given fertilizer."

Experimental Design Terms

• Control Group: The group not exposed to the experimental variable; used for comparison.

• Experimental Group: The group exposed to the variable being tested.

• Independent Variable: The factor that is changed or manipulated.

• Dependent Variable (Responding Variable): The factor that is measured.

• Controlled Variables: Factors kept constant across all groups.

Cells and Genetic Information

• Cell: The basic unit of life.

• Prokaryotic Cells: Lack a nucleus (e.g., bacteria, archaea).

• Eukaryotic Cells: Have a nucleus and membrane-bound organelles (e.g., plants, animals, fungi, protists).

• Genetic Information: DNA encodes instructions for life and is passed from generation to generation, connecting all living things through evolution.

Biological Organization (Least to Most Complex)

• Atom → Molecule → Organelle → Cell → Tissue → Organ → Organ System → Organism → Population → Community → Ecosystem → Biosphere

Key Terms

• Evolution: Change in populations over time; explains unity and diversity of life.

• Natural Selection: Mechanism of evolution where organisms better adapted to their environment tend to survive and reproduce.

• Adaptation: Inherited trait that increases an organism's chance of survival.

Chapter 2: The Chemical Context of Life

Atoms and Subatomic Particles

• Atom: Smallest unit of an element retaining its properties.

• Proton: Positive charge, found in nucleus, defines atomic number.

• Neutron: No charge, found in nucleus, contributes to atomic mass.

• Electron: Negative charge, orbits nucleus, involved in chemical bonding.

• Atomic Number: Number of protons in an atom.

• Atomic Mass: Sum of protons and neutrons. $\text{Atomic Mass} = \text{Number of Protons} + \text{Number of Neutrons}$

Isotopes

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

• Some isotopes are radioactive and can be used as tracers in biology.

Valence Electrons and Chemical Bonds

• Valence Electrons: Electrons in the outermost shell; determine chemical reactivity.

• Covalent Bond: Sharing of electron pairs between atoms.

• Polar Covalent Bond: Unequal sharing of electrons (e.g., in water).

• Nonpolar Covalent Bond: Equal sharing of electrons (e.g., in O2).

• Ionic Bond: Transfer of electrons from one atom to another, forming ions (e.g., NaCl).

• Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom (e.g., between water molecules).

Periodic Table Usage

• Elements are organized by atomic number.

• Groups indicate similar chemical properties.

Key Terms

• Element, Atom, Proton, Neutron, Electron, Valence Shell, Ions, Reactants, Products

Chapter 3: Water and Life

Properties of Water

• Cohesion: Water molecules stick to each other due to hydrogen bonding.

• Adhesion: Water molecules stick to other substances.

• Surface Tension: Measure of how difficult it is to stretch or break the surface of a liquid.

• High Specific Heat: Water can absorb or release large amounts of heat with little temperature change. Important for stabilizing temperatures in organisms and environments.

• Heat of Vaporization: Amount of energy required to convert 1g of liquid to gas.

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

• Hydrophilic: Substances that dissolve in water.

• Hydrophobic: Substances that do not dissolve in water.

Solutions, Molecular Mass, and Molarity

• Solution: Homogeneous mixture of solute dissolved in solvent.

• Molecular Mass: Sum of atomic masses in a molecule. Example: $\text{Molecular Mass of H_2O} = 2 \times 1 + 16 = 18$

• Molarity (M): Moles of solute per liter of solution. $\text{Molarity} = \frac{\text{Moles of Solute}}{\text{Liters of Solution}}$

pH Scale and Buffers

• pH: Measure of hydrogen ion concentration. $\text{pH} = -\log_{10}[H^+]$

• Acid: Substance that increases [H+] in solution (pH < 7).

• Base: Substance that decreases [H+] or increases [OH-] (pH > 7).

• Neutral: pH = 7 (pure water).

• Buffer: Substance that minimizes changes in pH by accepting or donating H+.

Key Terms

• Hydrogen Bonds, Cohesion, Adhesion, Surface Tension, High Specific Heat, Heat of Vaporization, Universal Solvent, Hydrophilic, Hydrophobic, Molecular Mass, Molarity, Hydrogen Ion, Hydroxide Ion, Hydronium Ion, pH, Acid, Base, Neutral, Buffers

Chapter 4: Carbon and the Molecular Diversity of Life

Importance of Carbon

• Carbon forms four covalent bonds, allowing for a diversity of stable organic molecules.

• Main elements in organic compounds: Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Sulfur (CHONPS).

Isomers of Carbon Compounds

• Structural Isomers: Differ in covalent arrangement of atoms.

• Cis-Trans Isomers (Geometric Isomers): Differ in spatial arrangement around double bonds.

• Enantiomers: Mirror images of each other; important in pharmaceuticals.

Carbon Skeletons

• Can be chains, branched chains, or rings.

Organic vs. Inorganic Molecules

• Organic Molecules: Contain carbon and hydrogen, often complex (e.g., glucose).

• Inorganic Molecules: Do not contain both carbon and hydrogen (e.g., CO2).

Functional Groups

• Hydroxyl (-OH): Alcohols; polar, forms hydrogen bonds.

• Carbonyl (C=O): Aldehydes and ketones; polar.

• Carboxyl (-COOH): Acts as an acid.

• Amino (-NH2): Acts as a base.

• Sulfhydryl (-SH): Forms disulfide bonds in proteins.

• Phosphate (-PO4): Contributes negative charge, found in ATP.

• Methyl (-CH3): Affects gene expression.

Key Terms

• Organic Compound, Inorganic Compound, Hydrocarbons, Chains, Rings, Branched Chains, Structural Isomer, Cis-trans Isomer, Enantiomers, Functional Groups, Hydroxyl, Carbonyl, Carboxyl, Amino, Sulfhydryl, Phosphate, Methyl

Chapter 5: The Structure and Function of Large Biological Molecules

Macromolecules: Overview

• Four major classes: Carbohydrates, Lipids, Proteins, Nucleic Acids.

• Monomers: Small building blocks (e.g., monosaccharides, amino acids, nucleotides).

• Polymers: Long chains of monomers (e.g., polysaccharides, polypeptides, nucleic acids).

Polymerization Reactions

• Dehydration Synthesis: Joins monomers by removing water.

• Hydrolysis: Breaks polymers into monomers by adding water.

Carbohydrates

• Monosaccharides: Simple sugars (e.g., glucose).

• Disaccharides: Two monosaccharides joined (e.g., sucrose).

• Polysaccharides: Many monosaccharides (e.g., starch in plants, glycogen in animals, cellulose in plants, chitin in fungi/arthropods).

• Functions: Energy storage, structural support.

Lipids

• Fats (Triglycerides): Glycerol + 3 fatty acids; energy storage.

• Saturated Fats: No double bonds; solid at room temperature.

• Unsaturated Fats: One or more double bonds; liquid at room temperature.

• Trans Fats: Unsaturated fats with trans double bonds; unhealthy.

• Phospholipids: Glycerol + 2 fatty acids + phosphate group; form cell membranes (amphipathic).

• Steroids: Four fused rings (e.g., cholesterol).

Proteins

• Amino Acids: Monomers of proteins; 20 types.

• Peptide Bond: Covalent bond between amino acids.

• Levels of Structure:

  • Primary: Sequence of amino acids.

  • Secondary: Alpha helices and beta sheets (hydrogen bonds).

  • Tertiary: 3D folding due to side chain interactions.

  • Quaternary: Multiple polypeptides together.

• Enzymes: Proteins that catalyze reactions; can be denatured by heat, pH, etc.

Nucleic Acids

• Nucleotides: Monomers (sugar, phosphate, nitrogenous base).

• DNA: Double helix, antiparallel strands, bases A-T, G-C.

• RNA: Single-stranded, bases A-U, G-C.

• Functions: Store and transmit genetic information, gene expression (transcription/translation).

Key Terms

• Polymer, Monomer, Dehydration Synthesis, Hydrolysis, Carbohydrates, Monosaccharides, Disaccharides, Polysaccharides, Starch, Glycogen, Chitin, Cellulose, Fats, Glycerol, Fatty Acids, Phospholipids, Steroids, Triglyceride, Saturated Fat, Unsaturated Fat, Trans Fat, Amphipathic, Phospholipid Bilayer, Cholesterol, Protein, Amino Acid, Enzymes, Peptide Bond, Peptides, Denatured, Biological Catalyst, Nucleic Acid, Nucleotide, DNA, RNA, Bases (A, T, G, C, U), Antiparallel, tRNA, rRNA, mRNA, Gene Expression (Transcription/Translation)

Macromolecule	Monomer	Polymer	Function	Example
Carbohydrate	Monosaccharide	Polysaccharide	Energy, Structure	Starch, Glycogen, Cellulose
Lipid	Fatty Acid, Glycerol	Triglyceride, Phospholipid	Energy Storage, Membranes	Fats, Oils, Phospholipids
Protein	Amino Acid	Polypeptide	Catalysis, Structure, Transport	Enzymes, Hemoglobin
Nucleic Acid	Nucleotide	DNA, RNA	Genetic Information	DNA, RNA

Additional info: This guide expands on the provided review outline with academic definitions, examples, and context for each topic, ensuring a comprehensive and self-contained study resource for introductory biology students.