Biology 120 Exam 1 - Chapters 1-5 (Vocabulary)

Vocabulary flashcards covering key terms and definitions from Chapters 1–5 of Biology 120.

Atom

The smallest unit of matter that preserves the identity of an element.

Molecule

A stable group of atoms held together by chemical bonds.

Cell

The basic unit of life; the smallest unit capable of performing life processes.

Tissue

A group of similar cells performing a common function.

Organ

A structure composed of two or more tissues working together.

Organ System

A group of organs that collaborate to perform a major body function.

Organism

An individual living thing.

Population

All individuals of a species living in a given area.

Community

Different populations living together in an area.

Ecosystem

A community plus the physical environment.

Biosphere

All life on Earth and its environments.

Metabolism

All chemical reactions in an organism that maintain life.

Growth and Development

Increase in size and complexity of an organism.

Reproduction

The production of offspring.

Response to Environment

Ability to react to stimuli from the environment.

Homeostasis

Maintenance of stable internal conditions.

Organization

Structured, ordered arrangement of biological systems.

Evolutionary adaptation

Genetic changes over time that improve fitness.

Science

Systematic study based on observation, experimentation, and evidence.

Domain

The largest taxonomic level in the DKPCOFGS hierarchy.

Kingdom

Second highest taxonomic rank after domain.

Phylum

Taxonomic rank below kingdom.

Class

Taxonomic rank below phylum.

Order

Taxonomic rank below class.

Family

Taxonomic rank below order.

Genus

Taxonomic rank below family.

Species

Smallest taxonomic unit; organisms that can interbreed.

Bacteria

Prokaryotic domain; bacteria.

Archaea

Prokaryotic domain; often in extreme environments.

Eukarya

Domain of all eukaryotic organisms.

Binomial nomenclature

Two-word format for scientific names (Genus species).

Genus species

Example of binomial name; italicized.

Homo sapiens

Human species as an example of binomial nomenclature.

Scientific Theory

Well-supported explanation backed by extensive evidence.

Everyday Theory

A guess or hypothesis not necessarily well-supported.

Control Group

Group with no treatment, used for baseline comparison.

Experimental Group

Group that receives the tested treatment.

Variable

Factor that can change in an experiment.

Independent Variable

Factor deliberately changed by the researcher.

Dependent Variable

Measured outcome of the experiment.

Observation

Information gathered through senses or instruments.

Question

Inquiry asked about a phenomenon or process.

Hypothesis

Testable educated guess predicting an outcome.

Experiment

Procedure used to test a hypothesis.

Analysis

Examination and interpretation of data.

Conclusion

Judgment about whether data support the hypothesis.

Nucleus

Center of an atom; contains protons and neutrons.

Proton

Positively charged subatomic particle in the nucleus.

Neutron

Electrically neutral subatomic particle in the nucleus.

Electron

Negatively charged subatomic particle orbiting the nucleus.

Atomic Number

Number of protons in the nucleus; defines the element.

Ion

Atom with a net charge due to gain or loss of electrons.

Cation

Positively charged ion.

Anion

Negatively charged ion.

Ionic Bond

Bond formed by transfer of electrons creating ions.

Covalent Bond

Bond formed by sharing electrons between atoms.

Hydrogen Bond

Weak attraction between polar molecules.

Octet Rule

Atoms tend to have eight electrons in outer shell (H ≈ 2).

Water polarity

Water is a polar molecule with uneven charge distribution.

Hydrogen bonding

Attractive interaction between a hydrogen atom and another electronegative atom.

High specific heat

Water’s capacity to resist temperature changes.

Cohesion

Water molecules sticking to each other.

Adhesion

Water molecules sticking to other surfaces.

Universal solvent

Water dissolves many substances.

Acid

Substance that donates H+ ions; pH < 7.

Base

Substance that accepts H+ ions or releases OH-; pH > 7.

Buffer

Substance that resists pH changes by releasing/absorbing H+.

Monosaccharide

Simple sugar; monomer of carbohydrates.

Glucose

A common six-carbon monosaccharide; main energy source.

Fructose

Six-carbon monosaccharide found in fruits.

Galactose

Six-carbon monosaccharide; component of lactose.

Starch

Plant storage polysaccharide composed of glucose.

Glycogen

Animal storage polysaccharide; glucose polymer.

Cellulose

Plant structural polysaccharide; glucose polymer with different linkages.

Triglyceride

Glycerol + three fatty acids; main form of dietary fat.

Saturated

Fatty acids with no double bonds; typically solid at room temp.

Unsaturated

Fatty acids with one or more double bonds; typically liquid.

Phospholipid

Lipid with glycerol, two fatty acids, and a phosphate group; forms cell membranes.

Sterol

Lipid with a ring structure; cholesterol is a key example.

Cholesterol

Sterol molecule important for membrane structure and fluidity.

Protein

Macromolecule with diverse roles including catalysis, structure, transport, signaling.

Enzyme

Protein that speeds up a chemical reaction.

Monomer

Small building block that polymerizes to form a macromolecule.

Amino acid

Monomer of proteins; linked by peptide bonds.

Peptide bond

Bond joining amino acids in a protein.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Localized folding patterns: alpha helices and beta sheets.

Tertiary structure

Three-dimensional folding of a single polypeptide.

Quaternary structure

Arrangement of multiple polypeptide subunits.

Denaturation

Loss of protein structure and function due to heat, pH, or chemicals.

Nucleic Acids

Polymers made of nucleotides (DNA and RNA).

Nucleotide

Monomer of nucleic acids.

DNA

Deoxyribonucleic acid; stores genetic information.

RNA

Ribonucleic acid; involved in protein synthesis.

Ribosome

Molecular machine where protein synthesis occurs.

Golgi apparatus

Organelle that modifies, sorts, and packages proteins.

Lysosome

Organelle that digests waste and cellular debris.

Vacuole

Storage organelle; large central vacuole in plants.

Mitochondrion

Organelle producing ATP via cellular respiration.

Chloroplast

Organelle where photosynthesis occurs in plants.