Chapter 1: Cells: The Fundamental Units of Life

A comprehensive set of vocabulary-style flashcards covering core concepts from Chapter 1 of Essential Cell Biology (5th edition), including cell unity, prokaryotic/eukaryotic cells, organelles, microscopy techniques, model organisms, and genome concepts.

Unity and diversity of cells

All living cells share a similar basic chemistry and fundamental features, but vary widely in appearance and function.

Basic chemistry of living cells

Living cells use a common set of chemical building blocks and reactions despite diverse forms and orga nization.

Self-replicating collections of catalysts

Cells function as systems where catalytic molecules drive reactions and replication to sustain life.

Ancestral cell

All living cells are thought to have evolved from a single common ancestor.

Genes

Instructions encoded in DNA that direct the form, function, and behavior of cells and organisms.

DNA

Deoxyribonucleic acid; the genetic material that stores hereditary information.

RNA

Ribonucleic acid; involved in transcription and translation and acts as an intermediary in gene expression.

Proteins

Chains of amino acids that perform most cellular functions and form cellular structures.

Nucleotides

The building blocks of DNA and RNA.

Replication

Synthesis of DNA to copy genetic material for cell division.

Transcription

Synthesis of RNA from a DNA template.

Translation

Synthesis of proteins from mRNA at ribosomes.

Central dogma

Genetic information flows from DNA to RNA to protein.

Chromosome

A structured DNA-protein complex that carries genetic information.

Nucleus

The organelle that stores genetic information and coordinates gene expression.

Nuclear envelope

Double-membrane layer that surrounds the nucleus.

Mitochondrion

Organelle that generates usable energy from food molecules; often called the powerhouse.

Chloroplast

Organelle that captures light energy for photosynthesis in plants and algae.

Endoplasmic reticulum (ER)

Network of membranes involved in protein and lipid synthesis; rough ER has ribosomes, smooth ER does not.

Golgi apparatus

Organelle that processes, sorts, and ships proteins and lipids in vesicles.

Ribosome

Molecular machine that synthesizes proteins by translating mRNA.

Lysosome

Organelle containing enzymes for digestion of cellular waste and macromolecules.

Peroxisome

Organelle involved in detoxification and lipid metabolism.

Vesicle

Membrane-bound sac used to transport and store substances within the cell.

Cytosol

A concentrated aqueous gel of large and small molecules that fills the cell and is the site of numerous reactions.

Cytoskeleton

A network of protein filaments (microtubules, actin) that supports shape and enables movement.

Plasma membrane

Phospholipid bilayer that encloses the cell and regulates entry and exit of substances.

Cell wall

Rigid layer outside the plasma membrane in plants and many bacteria that provides structure and protection.

Prokaryotic cell

Cell type lacking a defined nucleus; includes Bacteria and Archaea.

Eukaryotic cell

Cell type with a defined nucleus and membrane-bound organelles.

Bacteria

One of the two prokaryotic domains; diverse and abundant microorganisms.

Archaea

One of the two prokaryotic domains; distinct from bacteria in genetics and biochemistry.

Model organisms

Species used to study basic biology due to ease of experimentation and relevance to other organisms (e.g., E. coli, yeast, Arabidopsis, Drosophila, C. elegans, mice).

E. coli

A bacterium used as a model prokaryote in genetics and molecular biology.

Saccharomyces cerevisiae

Baker’s yeast; a simple eukaryote used as a model organism.

Arabidopsis thaliana

Model plant species widely used in plant biology.

Drosophila melanogaster

Fruit fly; a key model organism in genetics and development.

Caenorhabditis elegans

Nematode worm; a model organism for developmental biology and genetics.

Genome size

Total amount of DNA contained in an organism's haploid genome, often measured in nucleotide pairs.

Protein-coding genome

Part of the genome that contains genes encoding proteins.

Genes vs genomes

Genes are units of heredity; genomes encompass the entire genetic material of an organism.

Model organisms and genomics

Studying model organisms helps reveal conserved genetic and cellular mechanisms across species.

Fluorescence microscopy

Microscopy that uses fluorescent dyes to label and visualize specific molecules.

Conventional light microscopy

Light-based imaging that magnifies up to about 1000x and resolves details near 0.2 μm.

Confocal fluorescence microscopy

A fluorescence technique that scans with a laser to produce optical sections and 3D imaging.

Super-resolution microscopy

A set of methods that surpass the conventional light microscopy resolution limit (~200 nm) to ~20 nm.

Transmission electron microscopy (TEM)

Electron-based microscopy providing high-resolution images of thin sections, up to ~1 nm resolution.

Scanning electron microscopy (SEM)

Electron-based microscopy that images surfaces with three-dimensional detail, ~3–20 nm resolution.

Resolution

The ability to distinguish two close objects as separate entities; limited by wavelength in light microscopy.

Light path components

Condenser, objective, tube lens, and eyepiece—essential elements to form an image in a light microscope.

Fixed samples

Tissues chemically fixed and sectioned for staining and visualization under the light microscope.

Living cells imaging

Observing living cells with minimal disruption, using methods like phase-contrast and interference-contrast optics.

Fluorescent probes

Fluorescent molecules or dyes used to label specific cellular components for visualization.

Fluorescent antibodies

Antibodies conjugated to fluorescent dyes that bind selectively to target molecules.

GFP

Green fluorescent protein used as a fluorescent marker to study protein localization and dynamics.

Optical section

A thin slice of a specimen produced by scanning or focusing at a specific depth in confocal microscopy.

Endocytosis

Process by which cells import material via vesicle formation from the plasma membrane.

Exocytosis

Process by which cells export materials via vesicle fusion with the plasma membrane.

Internal membranes

Membranes within the cell (ER, Golgi, vesicles) that create compartments with distinct functions.

Golgi apparatus architecture

Organelles with cis and trans faces that modify and sort proteins and lipids.

Mitochondrial membranes

Two membranes (outer and inner) that enclose the mitochondrial matrix and drive energy production.

Chloroplast membranes

Double membranes surrounding chloroplasts where photosynthesis occurs.

Nucleolus

A subnuclear structure where ribosomal RNA is synthesized and ribosome assembly begins.

Cytosol versus cytoplasm

Cytosol is the aqueous gel inside cells; cytoplasm includes cytosol plus organelles and inclusions.

Historical landmarks in cell biology

Key discoveries that revealed cell structure and organization over time (microscopy, organelles, membranes, cytoskeleton, GFP, super-resolution).