BIO 1111 Study Guide: Introduction to Biology and Basic Chemistry (Chapters 1-4)

Unit 1: Introduction to Biology and Basic Chemistry

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

This chapter introduces the foundational concepts of biology, the characteristics of life, and the scientific method. Understanding these principles is essential for further study in biological sciences.

• Biology: The scientific study of life and living organisms, including their structure, function, growth, evolution, distribution, and taxonomy.

• Characteristics of Life:

  • Order (organized structure)

  • Regulation (homeostasis)

  • Growth and development

  • Energy processing

  • Response to environment

  • Reproduction

  • Evolutionary adaptation

• Cell Theory: All living things are composed of cells; the cell is the basic unit of life; all cells arise from pre-existing cells.

• Types of Organisms:

  • Unicellular: Single-celled organisms (e.g., Escherichia coli)

  • Multicellular: Organisms composed of multiple cells (e.g., humans, plants)

  • Prokaryotic: Cells without a nucleus (e.g., bacteria, archaea)

  • Eukaryotic: Cells with a nucleus (e.g., animals, plants, fungi, protists)

• Three Domains of Life:

  • Bacteria: Prokaryotic, unicellular organisms

  • Archaea: Prokaryotic, often extremophiles

  • Eukarya: Eukaryotic organisms (includes plants, animals, fungi, protists)

• Hierarchy of Classification: Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species

• DNA as the Molecule of Inheritance: DNA stores genetic information and is passed from parent to offspring, ensuring continuity of life.

• Evolution: Change in the genetic composition of a population over time.

• Natural Selection: Process by which organisms with advantageous traits survive and reproduce, leading to adaptation.

• Adaptations: Traits that enhance survival and reproduction, arising through natural selection.

• Tree of Life: Diagram showing evolutionary relationships among organisms.

• Scientific Method Steps:

  1. Observation

  2. Question

  3. Hypothesis

  4. Experiment

  5. Data Collection

  6. Analysis

  7. Conclusion

• Hypothesis vs. Theory: A hypothesis is a testable explanation; a theory is a well-supported, broad explanation.

• Support vs. Prove: Hypotheses can be supported or disproved, but not proven absolutely due to the possibility of new evidence.

• Control Group vs. Experimental Group: Control group receives no treatment; experimental group receives the variable being tested.

• Variables:

  • Controlled Variables: Kept constant

  • Independent Variable: Manipulated by the experimenter

  • Dependent Variable: Measured outcome

• Qualitative vs. Quantitative Data:

  • Qualitative: Descriptive (e.g., color, shape)

  • Quantitative: Numerical (e.g., height, mass)

Chapter 2: The Chemical Context of Life

This chapter covers the basic chemical principles underlying biological processes, including atomic structure, bonding, and chemical reactions.

• Matter: Anything that has mass and occupies space.

• Element: A substance that cannot be broken down into simpler substances by chemical means.

• Periodic Table: Reference for atomic symbol, atomic number, and atomic mass.

• Mass Number: Sum of protons and neutrons in an atom.

• Main Elements in Living Organisms: Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N) — make up ~96% of living matter.

• Element vs. Atom: An element is a type of atom; an atom is the smallest unit of an element.

• Subatomic Particles:

  • Proton: Positive charge

  • Neutron: No charge

  • Electron: Negative charge

• Atomic Structure: Protons and neutrons in nucleus; electrons in shells around nucleus.

• Electron Shells: K (2 electrons), L (8 electrons), M (18 electrons)

• Excited Electron: Electron absorbs energy and moves to a higher shell.

• Valence Shell: Outermost electron shell; Valence Electrons: Electrons in the valence shell.

• Chemical Properties: Determined by valence electrons; atoms bond to achieve stable electron configurations.

• Stable (Inert) Atom: Full valence shell; Unstable Atom: Incomplete valence shell.

• Charged Atom (Ion): Atom with unequal numbers of protons and electrons; Neutral Atom: Equal numbers.

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

• Ion: Charged atom; Cation: Positive charge; Anion: Negative charge.

• Atomic Diagrams: Bohr model (shells), Lewis dot (valence electrons).

• Molecular Formula vs. Structural Formula: Molecular shows types and numbers of atoms; structural shows arrangement.

• Covalent Bond: Sharing of electrons; Single: 1 pair; Double: 2 pairs; Triple: 3 pairs.

• Electronegativity: Atom's ability to attract electrons; determines bond polarity.

• Polar Covalent Bond: Unequal sharing; Non-polar: Equal sharing.

• Ionic Bond: Transfer of electrons; forms ionic compounds (e.g., NaCl).

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

• Chemical Reaction: Making/breaking chemical bonds; reactants → products.

• Chemical Equilibrium: Forward and reverse reactions occur at equal rates.

Chapter 3: Water and Life

This chapter explores the unique properties of water and its critical role in supporting life.

• Water Formula: Molecular: H2O; Structural: O bonded to two H atoms.

• Polarity of Water: Oxygen is more electronegative, creating partial charges.

• Hydrogen Bonds: Form between water molecules, leading to unique properties.

• Properties of Water:

  • Cohesion: Water molecules stick together (surface tension)

  • Adhesion: Water molecules stick to other substances

  • High Specific Heat: Water resists temperature change

  • High Heat of Vaporization: Requires much energy to evaporate

  • Lower Density as Solid: Ice floats; important for aquatic life

  • Good Solvent: Dissolves many substances

• Cohesion vs. Adhesion: Cohesion is attraction between water molecules; adhesion is attraction to other surfaces. Capillary Action: Movement of water in plants.

• Hydrophilic: Water-loving; dissolves in water. Hydrophobic: Water-fearing; does not dissolve.

• Importance of Liquid Water: Essential for biochemical reactions and life processes.

• High Heat Capacity: Water buffers temperature changes, stabilizing environments.

• High Heat of Vaporization: Evaporation cools organisms (e.g., sweating).

• Ice Floats: Due to lower density; insulates aquatic life in winter.

• Water in Measurements: Basis for temperature (Celsius), mass (gram), and energy (calorie).

• Solution: Solvent (e.g., water) dissolves solute (e.g., salt).

• Aqueous Solution: Solution where water is the solvent.

• Molecular Weight: Sum of atomic masses in a molecule.

• Mole: 6.022 x 1023 particles (Avogadro's number); used to count atoms/molecules.

• Calculating Moles and Mass:

  • $\text{Moles} = \frac{\text{Mass (g)}}{\text{Molar Mass (g/mol)}}$

  • $\text{Mass (g)} = \text{Moles} \times \text{Molar Mass (g/mol)}$

• Molarity: Measure of concentration; $\text{Molarity} = \frac{\text{Moles of solute}}{\text{Liters of solution}}$

• Percentage: $\text{Percent} = \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100$

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

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

• Acids: Increase H+ concentration; Bases: Decrease H+ concentration.

• Buffers: Maintain pH by absorbing or releasing H+.

Chapter 4: Carbon and the Molecular Diversity of Life

This chapter discusses the importance of carbon in organic molecules and the diversity created by functional groups and isomers.

• Inorganic vs. Organic Substances:

  • Inorganic: Does not contain carbon-hydrogen bonds (e.g., NaCl, H2O)

  • Organic: Contains carbon-hydrogen bonds (e.g., glucose, proteins)

• Hydrocarbon Structure: Chains or rings of carbon atoms bonded to hydrogen.

• Functional Groups: Chemical groups attached to hydrocarbons, affecting properties.

  • Hydroxyl (-OH): Found in alcohols

  • Carbonyl (C=O): Found in ketones and aldehydes

  • Keto (C=O within carbon chain): Found in ketones

  • Aldehyde (C=O at end): Found in aldehydes

  • Carboxyl (-COOH): Found in organic acids

  • Amino (-NH2): Found in amino acids

  • Sulfhydryl (-SH): Found in proteins

  • Phosphate (-PO4): Found in nucleic acids

  • Methyl (-CH3): Found in many organic molecules

• Isomers: Molecules with same formula but different structures.

  • Structural Isomers: Different covalent arrangements

  • Geometric Isomers (cis-trans): Different spatial arrangement around double bonds

  • Enantiomers: Mirror-image isomers (stereoisomers)

Example Table: Functional Groups and Their Properties

Functional Group	Structure	Common Molecule	Property
Hydroxyl	-OH	Alcohols	Polar, forms hydrogen bonds
Carbonyl	C=O	Ketones, Aldehydes	Polar
Carboxyl	-COOH	Organic acids	Acidic
Amino	-NH2	Amino acids	Basic
Sulfhydryl	-SH	Proteins	Forms disulfide bonds
Phosphate	-PO4	Nucleic acids	Negative charge
Methyl	-CH3	Many molecules	Nonpolar

Example: Glucose and fructose are structural isomers; cis-trans isomers differ in arrangement around double bonds; enantiomers are mirror images (e.g., L- and D-amino acids).

Additional info: Academic context and examples have been added to ensure completeness and clarity for exam preparation.