CHAPTER 1: Foundations of Life and Scientific Inquiry

Properties of Life

Living organisms share several key properties that distinguish them from non-living matter.

• Order: Organized structure, often in the form of cells.

• Regulation: Ability to maintain stable internal conditions (homeostasis).

• Growth and Development: Consistent growth and development controlled by inherited DNA.

• Energy Processing: Use of energy to power activities and chemical reactions.

• Response to Environment: Ability to respond to environmental stimuli.

• Reproduction: Ability to produce new organisms.

• Evolutionary Adaptation: Populations evolve over generations through adaptations.

Unifying Themes in Biology

Biology is organized around several unifying themes that connect all forms of life.

• Organization: Life is structured in a hierarchical manner.

• Information: Genetic information is stored and transmitted via DNA.

• Energy and Matter: Life requires energy transfer and transformation.

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

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

Levels of Biological Organization

Biological systems are organized from smallest to largest:

• Atoms → Molecules → Organelles → Cells → Tissues → Organs → Organ Systems → Organisms → Populations → Communities → Ecosystems → Biosphere

Structure and Function

Structure and function are closely related in biology; the shape of a structure often determines its function.

• Example: The structure of red blood cells (biconcave shape) increases surface area for gas exchange.

Feedback Regulation

Biological systems use feedback mechanisms to regulate processes.

• Negative Feedback: The output reduces the original effect of the stimulus (e.g., body temperature regulation).

• Positive Feedback: The output enhances the original stimulus (e.g., blood clotting).

Domains of Life

All life is classified into three domains:

• Bacteria

• Archaea

• Eukarya

Charles Darwin and Evolution

Charles Darwin proposed the theory of natural selection, explaining how species evolve over time due to heritable traits that enhance survival and reproduction.

Scientific Method

Scientists use a systematic process to investigate the natural world:

• Observation

• Question

• Hypothesis

• Experiment

• Analysis

• Conclusion

Experiments may be controlled, with independent and dependent variables.

• Independent Variable: The factor manipulated by the researcher.

• Dependent Variable: The factor measured in response.

CHAPTER 2: Chemistry of Life

Importance of Chemistry in Biology

Understanding basic chemistry is essential for studying biological processes, as all life is composed of chemical elements and reactions.

Essential Elements

Four elements make up about 96% of living matter: carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).

Atomic Structure

• Atom: Smallest unit of matter, composed of protons, neutrons, and electrons.

• Atomic Number: Number of protons in the nucleus.

• Mass Number: Sum of protons and neutrons.

Periodic Table

The periodic table organizes elements by increasing atomic number and similar chemical properties.

Chemical Bonds

• Covalent Bonds: Atoms share electrons.

• Ionic Bonds: Transfer of electrons from one atom to another.

• Hydrogen Bonds: Weak attractions between polar molecules.

• Van der Waals Interactions: Weak, transient interactions between molecules.

Chemical Reactions

• Reactants: Starting materials.

• Products: Substances formed.

• Chemical Equation Example:

Potential vs. Kinetic Energy

• Potential Energy: Stored energy (e.g., chemical bonds).

• Kinetic Energy: Energy of motion (e.g., heat, movement).

CHAPTER 3: Water and Life

Emergent Properties of Water

Water's unique properties make it essential for life:

• Cohesion: Water molecules stick together via hydrogen bonds.

• Moderation of Temperature: High specific heat helps stabilize temperatures.

• Expansion Upon Freezing: Ice is less dense than liquid water.

• Versatility as a Solvent: Water dissolves many substances.

Acids, Bases, and pH

• Acid: Substance that increases H+ concentration (e.g., HCl).

• Base: Substance that reduces H+ concentration (e.g., NaOH).

• pH Scale: Measures H+ concentration; ranges from 0 (acidic) to 14 (basic).

Formula:

CHAPTER 4: Carbon and the Molecular Diversity of Life

Carbon: The Backbone of Life

Carbon's ability to form four covalent bonds makes it the foundation of organic molecules.

Functional Groups

Functional groups are specific groups of atoms that confer particular properties to organic molecules.

ATP (Adenosine Triphosphate)

ATP is the primary energy carrier in cells.

• Chemical Formula:

• Releases energy when a phosphate group is removed (hydrolysis).

CHAPTER 5: Macromolecules

Macromolecules and Polymers

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

• Polymers: Long chains of monomers joined by covalent bonds.

• Dehydration Synthesis: Builds polymers by removing water.

• Hydrolysis: Breaks down polymers by adding water.

Carbohydrates

• Monomers: Monosaccharides (e.g., glucose, fructose).

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

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

• Bonds: Glycosidic linkages.

• Functions: Energy storage, structural support.

Lipids

• Types: Fats, phospholipids, steroids.

• Composition: Mostly hydrocarbons; fats are made from glycerol and fatty acids.

• Saturated vs. Unsaturated: Saturated fats have no double bonds; unsaturated have one or more.

• Phospholipids: Major component of cell membranes.

• Functions: Energy storage, membrane structure, signaling.

Proteins

• Monomers: Amino acids (20 types).

• Peptide Bonds: Link amino acids.

• Functions: Enzymes, structure, transport, defense, signaling.

• Enzymes: Proteins that catalyze biochemical reactions.

Levels of Protein Structure

• Primary: Sequence of amino acids.

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

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

• Quaternary: Association of multiple polypeptides.

Nucleic Acids

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

• Types: DNA and RNA.

• Bases: Purines (adenine, guanine), Pyrimidines (cytosine, thymine, uracil).

• Structure: DNA is double-stranded helix; RNA is usually single-stranded.

Additional info: These notes provide a comprehensive overview of foundational topics in General Biology, suitable for exam preparation and further study.