BIO1210 Comprehensive Study Notes Summary & Study Notes

🧩 Overview — Carbon Chemistry

Carbon has four valence electrons, which explains its ability to form four covalent bonds and build diverse backbones for biological molecules. The number and type of bonds (single vs. double) influence molecular geometry: a single bond allows free rotation and a straighter backbone, while a double bond introduces a kink that restricts rotation.

🔗 Hydrocarbons & Bonding

Hydrocarbons are molecules of carbon and hydrogen only; they form chains and rings that serve as the skeletons of many biomolecules. Hydrocarbon oxidation releases large amounts of energy, which is important in metabolism.

🔀 Isomers: Structural, Cis‑Trans, Enantiomers

• Structural (constitutional) isomers share a molecular formula but differ in the connectivity of atoms (e.g., pentane vs. 2‑methylbutane, both $C_5H_{12}$). Different connectivities yield different physical and chemical properties.
• Cis‑trans (geometric) isomers have the same covalent bonds but differ in the spatial arrangement around a double bond or ring, affecting shape and function.
• Enantiomers are non‑superimposable mirror images. Two enantiomers can have dramatically different biological activities; often only one enantiomer is biologically active.

🧪 Functional Groups

Functional groups are specific atom clusters that confer characteristic chemical behaviors to organic molecules. The type, number, and arrangement of functional groups determine reactivity and molecular interactions in biological systems.

💧 Water: Structure & Hydrogen Bonding

A water molecule, $H_2O$, is a polar covalent molecule. Oxygen is more electronegative and carries a partial negative charge (δ–), while the hydrogens carry partial positive charges (δ+). Hydrogen bonds form between the δ+ hydrogen of one water molecule and the δ– oxygen of another; these are intermolecular attractions that greatly influence water's properties.

❄️ States of Water & Anomalous Expansion

In ice, water molecules form a hexagonal lattice stabilized by stable hydrogen bonds, producing more open structure and lower density than liquid water. Liquid water at temperatures near 4°C is denser because hydrogen bonds are less stable and molecules pack more closely. This anomalous expansion (ice floats) is vital for aquatic life.

🌊 Water as Solvent & Thermal Properties

Water is a universal solvent: polar solutes and ions (e.g., $Na^+$, $Cl^-$) are stabilized by hydration shells. High specific heat (due to hydrogen bonds) means water absorbs/loses large amounts of heat with little temperature change, moderating climates and organismal temperatures (e.g., oceans warm slower than sand).

🌱 Cohesion, Adhesion, Capillary Action

Cohesion (water–water) and adhesion (water–other polar surfaces) underlie surface tension and capillary action, enabling processes like transport in plant xylem.

⚖️ Acids, Bases, pH & Buffers

• Acids increase free protons ($H^+$) in solution; bases increase hydroxide ($OH^-$) or accept $H^+$. Examples: $HCl$ dissociates to $H^+$ and $Cl^-$; $NaOH$ dissociates to $Na^+$ and $OH^-$.
• The pH scale measures $[H^+]$ (0–14; 7 neutral).
• Buffers resist abrupt pH shifts by donating or absorbing $H^+$ or $OH^-$, stabilizing biological pH.

⚛️ Basic Atomic Structure & Particles

Atoms consist of protons (positive, in nucleus), neutrons (neutral, in nucleus), and electrons (negative, in shells). The atomic number equals the number of protons (and, in neutral atoms, electrons). Valence electrons (outer shell) determine bonding behavior.

🔋 Electron Shells & Electron Configuration

Electron shells have characteristic capacities (first shell up to 2 e–, second up to 8 e–, etc.). Knowing an element's electron configuration predicts its valence and likely bonds (e.g., hydrogen has 1 valence electron; carbon has 4).

🧩 Isotopes & Radioisotopes

Isotopes are atoms of the same element with different neutron counts (e.g., $^{12}C$, $^{13}C$, $^{14}C$). Radioisotopes (like $^{14}C$) decay over time and are useful for dating (carbon‑14 dating uses a half‑life of ~5730 years) and medical imaging (PET scans).

🔗 Chemical Bonding: Covalent, Ionic, and Intermolecular Forces

• Covalent bonds: sharing of electron pairs (polar vs. nonpolar depends on electronegativity differences).
• Ionic bonds: electron transfer creates oppositely charged ions (cations and anions) held by electrostatic attraction; ionic compounds often form crystal lattices.
• Weak forces: hydrogen bonds, hydrophobic interactions, and Van der Waals forces are crucial for macromolecular structure and interactions.

🧬 Macromolecules & Polymers

Macromolecules are large polymers built from repeating monomers. Dehydration reactions join monomers (loss of $H_2O$); hydrolysis breaks polymers (addition of $H_2O$).

🍞 Carbohydrates

Monosaccharides (glucose, fructose, galactose) are monomers that form polysaccharides via glycosidic linkages. The orientation of glycosidic bonds (e.g., 1,4 alpha vs. 1,4 beta) dictates digestibility and structure — starch (α linkages) is digestible by many animals; cellulose (β linkages) is not.

🧪 Nucleic Acids

Nucleotides = nitrogenous base + sugar + phosphate. Phosphodiester linkages join nucleotides to form polynucleotides. DNA is typically double‑stranded with antiparallel backbones and complementary base pairing ($A$–$T$, $C$–$G$). RNA is usually single‑stranded and uses uracil instead of thymine.

🧴 Lipids

Lipids are hydrophobic molecules (fats, phospholipids, steroids). Triglycerides form from glycerol + fatty acids via ester linkages; saturated fatty acids lack double bonds and are typically solid at room temp, while unsaturated contain one or more double bonds and are liquid. Phospholipids have hydrophilic heads and hydrophobic tails and self‑assemble into bilayers.

🧠 Proteins: Amino Acids & Structure

Proteins are polymers of amino acids linked by peptide bonds. Protein structure levels:

• Primary: amino acid sequence
• Secondary: local folding (α‑helices, β‑sheets)
• Tertiary: overall 3D shape from R‑group interactions
• Quaternary: assembly of multiple polypeptides Single amino acid substitutions (e.g., sickle‑cell mutation) can disrupt structure and function.

🧭 Course Context & Scientific Process

BIO*1210 integrates foundational concepts and the scientific method: observation, hypothesis, experimentation, and iterative refinement. The course emphasizes applying these principles to real‑world problems.

🧫 Microbes & Antibiotic Resistance

Microbes (bacteria, fungi, protozoa) are central to human health and disease. The antibiotic resistance crisis arises from microbial evolution: selective pressure from antibiotic use favors resistant strains. Understanding spread, mechanisms, and stewardship is essential. Projects like Tiny Earth crowdsource soil microbes to discover new antibiotics.

🔬 Research Relevance

Learning objectives include characterizing life, explaining molecular structure–function relationships, and applying experimental thinking to problems like antibiotic discovery and tracking resistant pathogens.