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

1.1: Unifying Themes of Biology

Biology is the scientific study of life, encompassing a wide range of topics from molecular processes to ecosystem dynamics. Several unifying themes help organize biological knowledge.

• Emergent Properties: New properties arise at each level of biological organization that are not present at the preceding level. Example: The functioning of a cell is more than the sum of its organelles.

• Structure and Function: The form of a biological structure is closely related to its function. Example: The shape of bird wings enables flight.

• Genetic Information: DNA is the genetic material that stores and transmits hereditary information.

• Energy and Matter: Life requires the transfer and transformation of energy and matter. Example: Photosynthesis converts solar energy into chemical energy.

• Interactions: Organisms interact with each other and their environment, affecting both.

• Evolution: The core theme of biology, explaining the unity and diversity of life.

1.2: Evolution as the Core Theme of Biology

Evolution explains the diversity and unity of life. It is the process by which populations change over generations through mechanisms such as natural selection.

• Natural Selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring.

• Taxonomy: The science of classifying organisms into groups such as domain, kingdom, phylum, class, order, family, genus, and species.

1.3: Scientific Inquiry

Scientific inquiry involves making observations, forming hypotheses, and testing them through experiments. It uses both qualitative and quantitative data.

• Hypothesis: A testable explanation for an observation.

• Deductive Reasoning: Drawing specific conclusions from general principles.

• Inductive Reasoning: Drawing generalizations from specific observations.

• Controlled Experiment: An experiment in which only one variable is changed at a time.

Chapter 2: Atoms, Elements, Water, & Macromolecules

2.1: Matter, Elements, and Compounds

All matter is composed of elements, which are substances that cannot be broken down by chemical means. Compounds are substances formed from two or more elements in fixed ratios.

• Element: A substance consisting of one type of atom.

• Compound: A substance made of two or more elements chemically combined.

• Atoms: The smallest unit of an element, consisting of protons, neutrons, and electrons.

• Atomic Number: Number of protons in an atom.

• Mass Number: Sum of protons and neutrons.

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

2.2: Chemical Bonds

Atoms combine through chemical bonds to form molecules and compounds. The main types of bonds are covalent, ionic, and hydrogen bonds.

• Covalent Bond: Sharing of electron pairs between atoms.

• Ionic Bond: Transfer of electrons from one atom to another, resulting in oppositely charged ions.

• Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom (often oxygen or nitrogen).

• Valence Electrons: Electrons in the outermost shell, important for bonding.

2.3: Water and Life

Water is essential for life due to its unique properties, which arise from its polarity and ability to form hydrogen bonds.

• Cohesion: Water molecules stick to each other.

• Adhesion: Water molecules stick to other substances.

• High Specific Heat: Water can absorb a lot of heat before changing temperature.

• Evaporative Cooling: As water evaporates, it removes heat from surfaces.

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

• Ice Floats: Solid water is less dense than liquid water due to hydrogen bonding.

Chapter 3: The Structure & Function of Biological Molecules

3.1: Macromolecules and Polymers

Biological macromolecules are large molecules necessary for life, including carbohydrates, lipids, proteins, and nucleic acids. Most are polymers made from monomers.

• Polymer: A long molecule consisting of many similar building blocks (monomers).

• Dehydration Reaction: Joins monomers by removing water.

• Hydrolysis: Breaks polymers into monomers by adding water.

3.2: Carbohydrates

Carbohydrates are sugars and polymers of sugars. They serve as energy sources and structural materials.

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

• Disaccharides: Two monosaccharides joined by a glycosidic linkage (e.g., sucrose).

• Polysaccharides: Long chains of monosaccharides (e.g., starch, glycogen, cellulose).

3.3: Lipids

Lipids are hydrophobic molecules, including fats, phospholipids, and steroids. They are important for energy storage, membrane structure, and signaling.

• Fats: Composed of glycerol and fatty acids; used for energy storage.

• Phospholipids: Major component of cell membranes; have hydrophilic heads and hydrophobic tails.

• Steroids: Lipids with a carbon skeleton of four fused rings (e.g., cholesterol).

3.4: Proteins

Proteins are polymers of amino acids and perform a wide variety of functions in cells, including catalysis, structure, and transport.

• Amino Acids: Building blocks of proteins; 20 different types.

• Peptide Bond: Covalent bond linking amino acids.

• Protein Structure: Four levels—primary (sequence), secondary (alpha helix, beta sheet), tertiary (3D folding), quaternary (multiple polypeptides).

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

3.5: Nucleic Acids

Nucleic acids (DNA and RNA) store and transmit hereditary information. They are polymers of nucleotides.

• Nucleotide: Monomer consisting of a sugar, phosphate group, and nitrogenous base.

• DNA: Double helix structure; stores genetic information.

• RNA: Single-stranded; involved in protein synthesis.

• Base Pairing: Adenine pairs with thymine (DNA) or uracil (RNA); cytosine pairs with guanine.

Table: Comparison of Macromolecules

Key Equations and Concepts

• Atomic Mass:

• Molarity:

• pH:

Additional info: Some content was inferred and expanded for clarity and completeness, as the original notes were fragmented and abbreviated.