BIO121 Unit 1 Study Guide: Foundations of General Biology

Chapter 1: Biology – The Study of Scientific Life

Characteristics of Living Things

Biology is the scientific study of life. Living organisms share several key characteristics that distinguish them from non-living matter.

• Order: Living things are highly organized, from the molecular to the organismal level.

• 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 growth and maintenance.

• Response to Environment: Organisms respond to environmental stimuli.

• Reproduction: Living things reproduce their own kind.

• Evolutionary Adaptation: Populations evolve over generations through adaptations.

Biological Organization and Hierarchy

• Biological systems are organized into a hierarchy: atom → molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere.

• Each level has emergent properties not present at lower levels.

Classification of Living Things

• Living things are classified into three domains: Bacteria, Archaea, and Eukarya.

• Within domains, organisms are grouped into kingdoms and further subdivisions based on evolutionary relationships.

Interactions with the Environment

• Organisms interact with their environment and other organisms, exchanging energy and matter.

• Energy flows through ecosystems, while nutrients cycle within them.

Evolution and Natural Selection

• Charles Darwin's theory of evolution by natural selection explains the diversity and unity of life.

• Natural selection is the process by which organisms with advantageous traits survive and reproduce more successfully.

The Scientific Method

• Science relies on observation, hypothesis formation, experimentation, and analysis.

• Scientific theories are broad explanations supported by extensive evidence.

Vocabulary and Application

• Be able to define and apply bold-faced vocabulary terms from your textbook.

Chapter 2: The Chemical Basis of Life

Atoms, Elements, and Compounds

All matter is composed of atoms, which are the smallest units of elements. Elements combine to form compounds.

• Atom: Consists of protons, neutrons, and electrons.

• Element: A substance that cannot be broken down into other substances by chemical means.

• Compound: A substance consisting of two or more elements in a fixed ratio.

Atomic Structure

• Protons (+), neutrons (0), and electrons (−) are subatomic particles.

• Atomic number = number of protons; mass number = protons + neutrons.

• Isotopes are atoms of the same element with different numbers of neutrons.

Chemical Bonds

• Covalent bonds: Atoms share electrons.

• Ionic bonds: Atoms transfer electrons, resulting in oppositely charged ions.

• Hydrogen bonds: Weak attractions between polar molecules, important in water and biological molecules.

Water and Life

• Water is a polar molecule, forming hydrogen bonds that give it unique properties (cohesion, adhesion, high specific heat, solvent abilities).

• Acids and bases affect the pH of solutions; buffers help maintain stable pH in organisms.

Chemical Reactions

• Chemical reactions rearrange matter without creating or destroying atoms.

• Reactants are transformed into products.

Chapter 3: The Molecules of Cells

Organic Molecules and Carbon

Organic molecules are carbon-based compounds essential for life. Carbon's bonding properties allow for molecular diversity.

• Carbon forms four covalent bonds, enabling complex structures (chains, rings, branches).

• Functional groups (e.g., hydroxyl, carboxyl, amino, phosphate) confer specific chemical properties.

Macromolecules and Polymers

• Macromolecules are large molecules built from smaller units (monomers).

• Four major classes: carbohydrates, lipids, proteins, nucleic acids.

• Polymers are formed by dehydration synthesis (removal of water); broken down by hydrolysis (addition of water).

Carbohydrates

• Monosaccharides (simple sugars), disaccharides, and polysaccharides (complex carbohydrates).

• Functions: energy storage (starch, glycogen), structural support (cellulose, chitin).

Lipids

• Hydrophobic molecules including fats, phospholipids, and steroids.

• Functions: energy storage, membrane structure, signaling molecules.

Proteins

• Polymers of amino acids; structure determines function.

• Levels of structure: primary, secondary, tertiary, quaternary.

• Functions: enzymes, transport, support, defense, signaling.

Nucleic Acids

• DNA and RNA store and transmit genetic information.

• Central dogma: DNA → RNA → Protein.

Enzymes

• Proteins that catalyze biochemical reactions by lowering activation energy.

• Specificity determined by active site structure.

Vocabulary and Application

• Be able to define and apply bold-faced vocabulary terms from your textbook.

Table: Comparison of Major Macromolecules

Macromolecule	Monomer	Bond Type	Main Functions
Carbohydrates	Monosaccharides	Glycosidic linkage	Energy storage, structure
Lipids	Fatty acids, glycerol	Ester linkage	Energy storage, membranes, signaling
Proteins	Amino acids	Peptide bond	Catalysis, structure, transport, signaling
Nucleic Acids	Nucleotides	Phosphodiester bond	Genetic information storage and transfer

Key Equations

• Photosynthesis (generalized): $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$

• Cellular Respiration (generalized): $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$

Additional info: This study guide synthesizes the main learning objectives and foundational concepts from the first three chapters of a General Biology course, providing definitions, examples, and a comparative table for macromolecules.