General Biology Study Guide: Foundations, Chemistry of Life, Macromolecules, and Nucleic Acids

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This section introduces the criteria for life, the history of cell theory, and the scientific method as applied to biology.

Five Points to Define Life: Living things are organized, acquire materials and energy, reproduce, respond to stimuli, and adapt to their environment.
Spontaneous Generation: The outdated belief that living organisms could arise from nonliving matter.
Robert Hooke: First observed and named "cells" in cork tissue using a microscope.
Anton van Leeuwenhoek: Improved the microscope and observed single-celled organisms ("animalcules").
Rudolph Virchow's Theory: Proposed that all cells arise from pre-existing cells (Cell theory)
Redi and Pasteur's Experiments: Disproved spontaneous generation by showing that life does not arise from nonliving matter without contamination.
Chromosomal Theory of Inheritance: Genes are located on chromosomes, which are the basis for inheritance.
Scientific Method: A systematic approach involving observation, hypothesis, experimentation, and conclusion.

Understanding how organisms are classified and the role of natural selection in evolution.

Central Dogma of Molecular Biology: Information flows from DNA to RNA to protein.
Natural Selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring.
Types of Mutations: Changes in DNA sequence; can be beneficial, neutral, or harmful.
Three-Domain System: Classification of life into Bacteria, Archaea, and Eukarya.
Archaea vs. Bacteria: Both are prokaryotes, but Archaea are more closely related to Eukarya than to Bacteria.
Scientific Nomenclature: The system of naming organisms using genus and species (binomial nomenclature).
Phylogenetic Tree: A Diagram showing evolutionary relationships among organisms.

This section covers the basic chemistry relevant to biology, including atomic structure, isotopes, and types of chemical bonds.

Radioactive Isotopes: Atoms with unstable nuclei that decay, emitting radiation; used in dating and medical imaging.
Blocking Radioactive Isotopes: Shielding with lead or other dense materials can block radiation.
Electronegativity: The tendency of an atom to attract electrons in a bond.
Covalent Bonds: Atoms share electrons; can be polar (unequal sharing) or non-polar (equal sharing).
Hydrophilic vs. Hydrophobic: Hydrophilic substances interact with water; hydrophobic substances do not.
Ionic Bonds: Formed when electrons are transferred from one atom to another, creating charged ions.
Hydrogen Bonds: Weak attractions between a hydrogen atom and an electronegative atom (e.g., O or N).
Water's Properties: High specific heat, high heat of vaporization, cohesion, and adhesion due to hydrogen bonding.

Endothermic Reactions: Absorb energy from surroundings.
Exothermic Reactions: Release energy to surroundings.
Functional Groups: Specific groups of atoms within molecules that determine chemical reactivity (e.g., hydroxyl, carboxyl, amino).

Macromolecules are large, complex molecules essential for life, including proteins, carbohydrates, lipids, and nucleic acids.

Dehydration (Condensation) Reaction: Joins monomers by removing water to form polymers.
Hydrolysis: Breaks polymers into monomers by adding water.
Carbon Dioxide and the Ocean: CO2 dissolves in water, affecting pH and marine life.

Amino Acid Structure: Central carbon, amino group, carboxyl group, hydrogen atom, and R group (side chain).
Peptide Bond: Covalent bond formed between amino acids during protein synthesis.
Levels of Protein Structure:
- Primary: Sequence of amino acids.
- Secondary: Local folding (α-helix, β-sheet) due to hydrogen bonding.
- Tertiary: 3D shape formed by interactions among R groups.
- Quaternary: Association of multiple polypeptide chains.
Denaturation: Loss of protein structure due to heat, pH, or chemicals.
Reducing Agents: Chemicals that break disulfide bonds in proteins.
Protein Function: Determined by shape; mutations can alter function and cause disease (e.g., sickle cell anemia).
Chaperone Proteins: Assist in proper protein folding.
Myoglobin vs. Hemoglobin: Myoglobin stores oxygen in muscles; hemoglobin transports oxygen in blood.
Polypeptide vs. Peptide: Peptides are short chains of amino acids; polypeptides are longer and can form proteins.

Nucleic acids (DNA and RNA) store and transmit genetic information.

Nucleotide Structure: Composed of a phosphate group, a five-carbon sugar (ribose or deoxyribose), and a nitrogenous base.
Ribose vs. Deoxyribose: Ribose has a hydroxyl group at the 2' carbon; deoxyribose lacks it.
Purines and Pyrimidines: Purines (adenine, guanine) have two rings; pyrimidines (cytosine, thymine, uracil) have one ring.
Phosphodiester Bond: Links nucleotides in a nucleic acid chain.
Polymerization Reaction: Nucleotides are joined by dehydration synthesis, forming phosphodiester bonds.

Watson, Crick, and Franklin: Discovered the double helix structure of DNA; Franklin's X-ray diffraction images were critical.
Chargaff's Rule: In DNA, the amount of adenine equals thymine, and guanine equals cytosine.
DNA Synthesis Direction: DNA is synthesized in the 5' to 3' direction.
DNA Polymerase: The enzyme that synthesizes new DNA strands during replication.
Semi-Conservative Replication: Each new DNA molecule consists of one old strand and one new strand.
RNA vs. DNA: RNA contains ribose and uracil; DNA contains deoxyribose and thymine.

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Bases	A, T, G, C	A, U, G, C
Strands	Double-stranded	Single-stranded
Function	Genetic information storage	Protein synthesis, gene regulation

Some context and definitions were inferred to provide a complete, self-contained study guide.