Chapter 1: Cells: The Fundamental Units of Life

100 vocabulary flashcards to study key concepts from Chapter 1: Cells: The Fundamental Units of Life.

Cell

The basic unit of life; a small, membrane-bound unit that can grow, replicate, and carry out metabolism.

Unity and Diversity of Cells

The idea that all cells share a common chemistry but vary greatly in size, shape, and function.

Prokaryotic Cell

A cell that lacks a nucleus and other membrane-bound organelles; includes bacteria and archaea.

Eukaryotic Cell

A cell with a true nucleus and membrane-bound organelles; typically larger and more complex.

Nucleus

The organelle that houses most of the cell’s DNA and controls gene expression.

Nuclear Envelope

A double membrane surrounding the nucleus that regulates transport between nucleus and cytoplasm.

Chromosome

A DNA-protein structure that becomes visible during cell division and carries genetic information.

DNA

Deoxyribonucleic acid; the molecule that stores genetic information in genes.

RNA

Ribonucleic acid; transcribed from DNA and used to guide protein synthesis and regulate genes.

Central Dogma

The flow of genetic information from DNA to RNA to protein.

Protein

A large molecule made of amino acids that performs many cellular roles, including structure and catalysis.

Amino Acid

Building blocks of proteins; 20 standard amino acids assemble into proteins.

Gene

A DNA sequence that encodes an RNA or protein product.

Genome

The complete set of genetic material in an organism.

Self-Replication

The ability of cells to duplicate their genetic material and divide to form two daughter cells.

Virus

A non-cellular parasite that contains DNA or RNA but cannot reproduce on its own.

Ancestral Cell

The common ancestor of all modern cells, believed to exist over 3 billion years ago.

Mutation

A change in the DNA sequence that can alter gene function or phenotype.

Evolution

The process by which populations accumulate heritable changes over generations.

Sexual Reproduction

Reproduction by fusion of two cells, shuffling DNA to create diverse offspring.

Model Organism

A species used to study biology with results applicable to other organisms.

Escherichia coli (E. coli)

A small, rapidly growing bacterium used as a model organism in molecular biology.

Saccharomyces cerevisiae

Budding yeast; a simple eukaryote used to study basic cellular processes.

Arabidopsis thaliana

A small weed model plant with a small genome used in plant biology.

Drosophila melanogaster

The fruit fly; a foundational genetic model organism for development and genetics.

Caenorhabditis elegans

A transparent nematode worm used for developmental biology and genetics.

Zebrafish

Danio rerio; a vertebrate model organism with transparent embryos for development studies.

Mus musculus

The house mouse; a primary model organism for mammalian genetics and disease.

In Vitro

Experiments conducted outside a living organism, typically in culture.

Prokaryote

An organism whose cells lack a nucleus and other membrane-bound organelles.

Archaea

A domain of single-celled microorganisms distinct from bacteria; often extremophiles.

Bacteria

A domain of prokaryotic organisms with diverse metabolisms and shapes.

Mitochondrion

Organelle that generates ATP through cellular respiration; has its own DNA.

Chloroplast

Plant/algae organelle that carries out photosynthesis and contains its own DNA.

Endosymbiotic Theory

Idea that mitochondria and chloroplasts originated from engulfed bacteria living inside ancestral cells.

Golgi Apparatus

Organelle that modifies, sorts, and packages proteins for secretion or delivery.

Endoplasmic Reticulum

Network of membranes where most protein and lipid synthesis occurs; rough ER has ribosomes.

Ribosome

Molecular machine that translates RNA into proteins; composed of RNA and protein.

Lysosome

Organelle that digests cellular waste and ingested materials.

Peroxisome

Organelle for lipid metabolism and detoxification; contains enzymes that handle hydrogen peroxide.

Vesicle

Small membrane-bound sac that transports cargo between cellular compartments.

Endocytosis

Process by which cells take up external material by engulfing it at the plasma membrane.

Exocytosis

Process by which vesicles fuse with the plasma membrane to release contents outside.

Cytosol

Aqueous gel-like fluid inside the cell, excluding organelles; site of many reactions.

Cytoplasm

All the contents of the cell outside the nucleus, including cytosol and organelles.

Cytoskeleton

Network of protein filaments that gives the cell shape, aids movement, and organizes transport.

Actin Filaments

Thin filaments involved in cell movement and muscle contraction.

Microtubules

Thick, hollow tubes that organize chromosomes and serve as tracks for transport.

Intermediate Filaments

Filaments that provide mechanical strength to cells.

Nucleolus

Nuclear subregion where ribosomal RNA genes are transcribed.

Chromatin

DNA-protein complex that condenses into chromosomes during cell division.

Nuclear Pore

Channels in the nuclear envelope that regulate traffic between nucleus and cytoplasm.

Plasma Membrane

Lipid bilayer that encloses the cell, mediating transport and signaling.

Cell Wall

Rigid layer outside the plasma membrane in plants and some microbes; mainly cellulose.

Vacuole

Membrane-bound storage organelle; central vacuole in plants maintains turgor.

Mitochondrial DNA

Circular DNA within mitochondria, inherited with maternal bias in many species.

Chloroplast DNA

DNA within chloroplasts supporting photosynthesis-related genes.

ATP

Adenosine triphosphate; the cell’s primary energy currency.

Cell Respiration

Metabolic process that uses oxygen to produce ATP from nutrients; releases CO2.

Photosynthesis

Process by which light energy is converted to chemical energy in chloroplasts, producing sugars and O2.

Endomembrane System

Interconnected membranes (ER, Golgi, lysosomes) that coordinate protein and lipid trafficking.

Vesicle Trafficking

Movement of vesicles between organelles and membranes within the cell.

Macromolecular Crowding

High concentration of macromolecules in the cytosol affecting diffusion and reactions.

Homeostasis

Maintenance of a relatively constant internal environment in a cell or organism.

Evolutionary Conservation

Core cellular mechanisms that are preserved across diverse species due to common ancestry.

Gamete

A reproductive cell (egg or sperm) carrying half the genome.

Mutation (Neutral/Beneficial/Harmful)

DNA changes that can have neutral, advantageous, or deleterious effects on organisms.

Transcription

Process of copying a DNA sequence into RNA.

Translation

Process of decoding an RNA sequence into a string of amino acids (protein).

Genome Size vs Gene Count

Genomes vary in size; gene count does not always scale with genome length.

Homologous Genes

Genes in different species that share a common ancestral origin and often similar function.

Proteome

All the proteins expressed by a cell, tissue, or organism.

Polypeptide

A polymer chain of amino acids linked by peptide bonds; a precursor to protein.

Three Domains of Life

The classification of life into Bacteria, Archaea, and Eukarya.

CDC Genes

Cell-division cycle genes in yeast that regulate progression through the cell cycle.

Cyclin

A family of proteins that regulate the cell cycle by activating cyclin-dependent kinases.

Cdc2

A key cyclin-dependent kinase involved in triggering cell-cycle events; conserved across species.

Schizosaccharomyces pombe (S. pombe)

Fission yeast; rod-shaped, divides by fission; a model for cell-cycle studies.

Saccharomyces cerevisiae (S. cerevisiae)

Budding yeast; model eukaryote used to study cell division and basic biology.

Hartwell

L. Hunt? (Note: In context, researcher: Lee Hartwell, Nobel Prize for cell-cycle research.)

Nurse

Paul Nurse; Nobel Prize-winning researcher who demonstrated conservation of cell-cycle control.

Arabidopsis thaliana

Model plant with a small genome; widely used in plant biology.

Drosophila melanogaster

Fruit fly; classic model for genetics and development.

Caenorhabditis elegans

Nematode worm; transparent; complete genome; developmental biology model.

Zebrafish

Vertebrate model organism with transparent embryos used for development studies.

Mouse (Mus musculus)

Model mammal; extensively used in genetics and disease research.

Human

Homo sapiens; studied directly and through cultured human cells for health research.

In Vivo

Experiments conducted in living organisms.

In Vitro Cultures

Cultures grown outside a living organism, in a controlled environment.

DNA Replication

Process of copying DNA so each daughter cell gets a complete genome.

RNA Polymerase

Enzyme that synthesizes RNA from a DNA template during transcription.

Ribosome Localization

Ribosomes can be free in cytoplasm or bound to the rough endoplasmic reticulum.

Nucleosome

Unit of DNA winding around histone proteins to form chromatin (in context of chromatin).

Mitochondrial Genome

Genome contained within mitochondria; typically circular and separate from nuclear genome.

Chloroplast Genome

Genome contained within chloroplasts; supports photosynthesis-related genes.

Nucleotide

Building block of DNA and RNA; consists of a sugar, phosphate, and base.

Base Pairs

Pairs of nucleotides across DNA strands that encode genetic information.

DNA Code

The sequence of nucleotides that stores genetic instructions.

Genetic Regulation

Control of when and where genes are turned on or off.

Noncoding DNA

DNA that does not code for proteins but can regulate gene activity.