Exam 1 Study Guide: Chapters 1-2 (Introduction to Biology & Chemistry of Life)

Vocabulary flashcards covering key terms and concepts from Chapters 1 and 2, including organization, chemistry of life, and biomolecules.

Biological Organization

The hierarchical levels from cell to biosphere: cell, tissue, organ, organ system, organism, population, community, ecosystem, and biosphere.

Atom

The smallest unit of an element, composed of protons, neutrons, and electrons.

Molecule

Two or more atoms bonded together.

Cell

The structural and functional unit of life; the basic unit of life.

Tissue

A group of cells with a common structure and function (e.g., nervous tissue, leaf tissue).

Organ

A structure made of tissues working together to perform a specific task (e.g., brain, leaves).

Organ System

Several organs working together (e.g., nervous system).

Organism

An individual made up of several organ systems (e.g., human, tree).

Population

A group of individuals of the same species in a particular area.

Community

Interaction of various populations in a given area.

Ecosystem

A community plus the physical (abiotic) environment.

Biome

A large region characterized by its climate and typical communities (e.g., rainforest, desert).

Biosphere

All the ecosystems on Earth; the highest level of biological organization.

Homeostasis

Maintenance of a constant internal environment (e.g., body temperature, pH).

Metabolism

All chemical reactions in a cell; includes energy capture and use (e.g., photosynthesis).

Photosynthesis

Process by which plants convert solar energy into chemical energy (sugars).

Adaptation

Heritable traits that improve survival and reproduction, often via natural selection.

Evolution

Modification by descent; gradual changes in populations over time leading to new species.

Species

Interbreeding organisms that produce viable and fertile offspring.

Binomial Nomenclature

Two-part scientific name (Genus species) used to identify species.

Linnaeus

18th-century scientist who proposed the hierarchical taxonomy system.

Taxonomy

The science of identifying and classifying organisms into a hierarchical system.

Systematics

Determining the evolutionary relationships among organisms.

Observation

A data-gathering step in the scientific method from direct perception or literature.

Hypothesis

A tentative, testable statement about the natural world.

Prediction

A statement of expected results used to test a hypothesis.

Experiment

A controlled test designed to test a hypothesis, including variables and controls.

Fact

An observation repeatedly confirmed and generally accepted as true, though not absolute.

Law

A descriptive generalization about how some aspect of the natural world behaves under certain conditions.

Theory

A well-substantiated explanation that integrates facts, laws, and tested hypotheses.

Scientific Method

A cyclical process of observation, hypothesis, experimentation, and conclusion; not strictly linear.

Three Domains

Bacteria, Archaea, and Eukarya—the highest taxonomic ranks; Bacteria and Archaea are prokaryotes, Eukarya are eukaryotes.

Prokaryote

Organism lacking a nucleus (e.g., Bacteria and Archaea).

Eukaryote

Organism with a nucleus and membrane-bound organelles (e.g., plants, animals, fungi, protists).

Bacteria

Domain of prokaryotic organisms.

Archaea

Domain of prokaryotes often in extreme environments.

Eukarya

Domain containing protists, fungi, plants, and animals.

Protists

Mostly unicellular eukaryotes within Eukarya.

Fungi

Heterotrophic eukaryotes with chitin-containing cell walls.

Plants

Multicellular, photosynthetic eukaryotes with cell walls of cellulose.

Animals

Multicellular, heterotrophic eukaryotes.

Water

Polar molecule essential to life; solvent; exhibits cohesion, adhesion, high surface tension, high heat capacity; ice is less dense than liquid water.

Solvent

Substance that dissolves solutes to form a solution.

Hydrophilic

Water-loving; substances that readily dissolve in water.

Hydrophobic

Water-hating; substances that do not readily dissolve in water.

Cohesion

Attraction between water molecules.

Adhesion

Attraction between water molecules and other polar surfaces.

Surface Tension

The cohesive forces at the surface of a liquid that make it act as if its surface were covered with a tight skin.

pH

A scale (0-14) measuring hydrogen ion concentration; 7 is neutral; lower is acidic, higher is basic (alkaline).

Acid

A substance that increases H+ concentration, lowering pH.

Base

A substance that decreases H+ concentration, raising pH.

Buffer

A substance that helps maintain a stable pH by neutralizing added acids or bases.

Monosaccharide

Simple sugar; the building block of carbohydrates (e.g., glucose).

Disaccharide

Two monosaccharides linked together (e.g., sucrose, maltose).

Polysaccharide

Many monosaccharides linked; energy storage (glycogen, starch) or structural (cellulose, chitin).

Glucose

Most common monosaccharide and primary energy source.

Glycogen

Animal storage polysaccharide in liver and muscles.

Starch

Plant storage polysaccharide.

Cellulose

Plant structural polysaccharide forming cell walls.

Chitin

Structural polysaccharide in arthropods (exoskeletons) and some fungi.

Lipids

Macromolecules (fats, oils, phospholipids, steroids) that store energy, protect, and waterproof; mostly hydrophobic.

Glycerol

Backbone molecule for fats and phospholipids.

Fatty Acids

Long hydrocarbon chains that compose fats; can be saturated or unsaturated.

Phospholipid

Lipid with a hydrophilic head and two hydrophobic tails; primary component of cell membranes.

Steroid

Lipid with four fused rings; includes cholesterol and steroid hormones.

Saturated Fatty Acid

Fatty acid with no double bonds; typically solid at room temperature.

Unsaturated Fatty Acid

Fatty acid with one or more double bonds; usually liquid at room temperature.

Proteins

Macromolecules made of amino acids; perform structural, enzymatic, signaling, and transport roles; peptide bonds link amino acids.

Amino Acid

Monomer of proteins; building blocks linked by peptide bonds.

Peptide Bond

Covalent bond linking amino acids in a protein.

Nucleic Acids

DNA and RNA; polymers of nucleotides involved in genetic information and protein synthesis.

DNA

Deoxyribonucleic acid; double helix; stores genetic information; bases A, T, C, G.

RNA

Ribonucleic acid; usually single-stranded; bases A, U, C, G; involved in protein synthesis.