General Biology: Quiz 1/Exam 1 Review Study Notes (Chapters 1–3)

Chapter 1: Introduction to Biology

Characteristics of Living Things

• Order: Living things exhibit complex but ordered organization.

• Regulation: Organisms maintain stable internal conditions (homeostasis).

• Growth and Development: Organisms grow and develop according to specific instructions coded in their DNA.

• Energy Processing: Living things obtain and use energy for maintenance and growth.

• Response to Environment: Organisms respond to environmental stimuli.

• Reproduction: Organisms reproduce their own kind.

• Evolutionary Adaptation: Populations evolve over generations as individuals with traits best suited to their environment have greater reproductive success.

Two Basic Cell Types

• Prokaryotic Cells: Lack a nucleus and membrane-bound organelles; found in Bacteria and Archaea.

• Eukaryotic Cells: Have a nucleus and membrane-bound organelles; found in Eukarya (plants, animals, fungi, protists).

Three Domains of Life

• Bacteria: Prokaryotic, unicellular organisms.

• Archaea: Prokaryotic, often found in extreme environments.

• Eukarya: Eukaryotic organisms, including animals, plants, fungi, and protists.

Hierarchy of Life

• Biosphere → Ecosystem → Community → Population → Organism → Organ System → Organ → Tissue → Cell → Organelle → Molecule → Atom

Evolutionary Adaptation

• Definition: A trait that increases an organism's fitness and is favored by natural selection.

• Example: Camouflage in insects to avoid predators.

Chapter 2: Chemistry of Life

Elements, Atoms, and Compounds

• Element: A substance that cannot be broken down into other substances by chemical means (e.g., carbon, hydrogen).

• Compound: A substance consisting of two or more elements in a fixed ratio (e.g., H2O).

• Periodic Table: Organizes elements by atomic number and properties.

Atomic Structure

• Protons: Positively charged, found in nucleus; number determines atomic number.

• Neutrons: Neutral, found in nucleus; number plus protons equals mass number.

• Electrons: Negatively charged, orbit nucleus; involved in chemical bonding.

Isotopes and Ions

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

• Ion: Atom or molecule with a net electric charge due to loss or gain of electrons.

Octet Rule

• Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outer shell (stable configuration).

Chemical Bonds

• Ionic Bonds: Transfer of electrons from one atom to another (e.g., NaCl).

• Non-polar Covalent Bonds: Equal sharing of electrons (e.g., O2).

• Polar Covalent Bonds: Unequal sharing of electrons (e.g., H2O).

• Hydrogen Bonds: Weak attraction between a hydrogen atom and an electronegative atom (e.g., between water molecules).

pH and the pH Scale

• pH: Measure of hydrogen ion concentration; scale from 0 (acidic) to 14 (basic).

• Formula: $\text{pH} = -\log_{10}[H^+]$

Properties of Water

• Cohesion: Water molecules stick to each other (surface tension).

• Adhesion: Water molecules stick to other substances.

• States: Exists as solid, liquid, and gas at normal temperatures on Earth.

• High Specific Heat: Water resists temperature change.

• Solvent Properties: Water dissolves many substances ("universal solvent").

Chemical Reactions

• Reactants: Starting substances in a reaction.

• Products: Substances formed by the reaction.

• Catabolic Reactions: Break down molecules, releasing energy.

• Anabolic Reactions: Build complex molecules from simpler ones, requiring energy.

Chapter 3: Biomolecules

Organic Molecules

• Definition: Molecules containing carbon and hydrogen, often with oxygen, nitrogen, phosphorus, or sulfur.

• Examples: Carbohydrates, lipids, proteins, nucleic acids.

Functional Groups

• Specific groups of atoms within molecules that determine the chemical properties of those molecules (e.g., hydroxyl, carboxyl, amino, phosphate).

Carbohydrates

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

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

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

• Functions: Energy source, energy storage, structural support (cellulose in plants).

Lipids

• Types: Fats, oils, phospholipids, steroids.

• Components of Fats: Glycerol and fatty acids.

• Functions: Long-term energy storage, insulation, cell membrane structure (phospholipids), hormones (steroids).

Proteins

• Monomers: Amino acids.

• Functions: Enzymes, structural support, transport, defense, signaling, movement.

Nucleic Acids

• Monomers: Nucleotides (composed of a sugar, phosphate group, and nitrogenous base).

• Types: DNA and RNA.

• Functions: Store and transmit genetic information, direct protein synthesis.

Identification of Biological Molecules

• Be able to recognize the general structure of carbohydrates (ring structures), lipids (long hydrocarbon chains), proteins (amino acid chains with peptide bonds), and nucleic acids (phosphate-sugar backbone with nitrogenous bases).

• Example: Glucose is a six-carbon ring; triglycerides have three fatty acid chains attached to glycerol.

• Additional info: Practice with diagrams and models can help in visual identification.