General Biology 1: Cell Theory, Structure, and Function

A comprehensive set of vocabulary flashcards covering General Biology 1 concepts including cell theory, organelles, cell types, cell division (mitosis/meiosis), transport mechanisms, and biomolecules.

Cell

The structural and functional unit of life.

Homeostasis

An organism’s ability to keep a constant internal state.

Zacharias Janssen

The scientist who invented the first primitive microscope between 1585–1632.

Robert Hooke

The scientist who observed cork cells under a microscope between 1635–1703.

Francesco Redi

The scientist who disproved the spontaneous generation theory between 1626–1697.

Anton van Leeuwenhoek

The scientist who observed microorganisms using his own practical microscope between 1632–1723.

Matthias Schleiden

The scientist who proposed that all plants are composed of cells.

Theodor Schwann

The scientist who proposed that all animals are composed of cells.

Rudolf Virchow

The scientist who proposed that all cells come from pre-existing cells.

Principle 1 of Cell Theory

Every living organism consists of one or more cells.

Principle 2 of Cell Theory

The cell is the fundamental unit of life, being the smallest structural and functional unit in all organisms.

Principle 3 of Cell Theory

Cells come from pre-existing cells and contain hereditary material passed to daughter cells.

Plasma Membrane

The cell’s primary barrier that separates the cytoplasm from the external environment.

Fluid Mosaic Model

A model describing the membrane structure as a mosaic of proteins, sugars, and cholesterol with fluidity due to its natural viscosity.

Selective Permeability

A property of the lipid bilayer that only allows certain molecules to move into and out of the cell.

Cytoskeleton

A network of protein fibers that gives the cell its structural framework and serves functions such as the movement of organelles.

Microtubules

Cytoskeletal elements consisting of helically arranged globular proteins called tubulin ($\alpha$-tubulin and $\beta$-tubulin subunits).

Microfilaments

The thinnest cytoskeleton elements, consisting of long fibers of actin protein.

Intermediate Filaments

Cytoskeletal elements that provide structural integrity to the plasma membrane, help maintain cell shape, and anchor the nucleus.

Cytoplasm

The region where all different subcellular structures are suspended, composed of the semi-fluid cytosol.

Cell Wall

A rigid structure surrounding the cell membrane that helps maintain shape and prevents the cell from bursting.

Peptidoglycan

The material that makes up the cell wall in most bacteria.

Endosymbiotic Theory

A theory suggesting that mitochondria and chloroplasts originated when a large eukaryotic cell engulfed a prokaryote.

Nucleus

A prominent, usually oval structure in eukaryotic cells that houses DNA.

Nuclear Pores

Openings in the nuclear envelope that permit the passage of ribosomal subunits and mRNA.

Ribosomes

Organelles that use instructions from the nucleus, written in mRNA, to build proteins.

Rough Endoplasmic Reticulum

An organelle with thousands of attached ribosomes whose main role is to produce proteins.

Smooth Endoplasmic Reticulum

An organelle without attached ribosomes that produces lipids.

Golgi Bodies

Organelles that serve as a warehouse and processing center for products from the Endoplasmic Reticulum.

Lysosomes

One of the digestion centers of the cell, often involved in breaking down materials.

Peroxisomes

Organelles containing enzymes that serve as metabolic assistance and specialize in synthesizing and breaking down lipids.

Vacuoles

Organelles that serve as storage for water, organic nutrients, salts, sugar, and some weak acids.

Mitochondrion

Commonly known as the 'powerhouse of the cell,' it is where cellular respiration occurs.

Chloroplast

An organelle unique to plant and algae cells that performs photosynthesis.

Prokaryotic Cell

A type of cell lacking compartments, with genetic material enclosed in a nucleoid region rather than a nucleus.

Eukaryotic Cell

A compartmentalized cell type where genetic material is enclosed within a nucleus.

Ploidy

The number of sets of chromosomes that a cell or an organism has.

Diploid ($2n$)

A cell containing two sets of chromosomes; in humans, this number is $46$.

Haploid ($n$)

A cell containing one set of chromosomes; in humans, this number is $23$.

Tissues

Groups of cells with a common origin and function.

Microvilli

Specialized structures in the small intestine that increase surface area for the absorption of nutrients.

Cilia

Hair-like structures in the respiratory tract that prevent mucus, bacteria, and dirt from entering the lungs.

Flagella

Tail-like structures that provide motility to cells, such as sperm or Euglena.

Cell Junctions

Structures in epithelial cells responsible for connecting adjacent cells, including tight, adherens, desmosomes, and gap junctions.

Trichomes

Epidermal outgrowths in plants responsible for preventing insect attacks, shading leaves, and trapping insects.

Root Hairs

Tiny hair-like structures in plants that facilitate the absorption of water from the substrate.

Mesophyll Cells

The primary site of photosynthesis in plant leaves, comprised of palisade and spongy cells.

Xylem and Phloem

Vascular tissues in plants responsible for transporting water, minerals, and food.

Cell Cycle

The series of events that a cell goes through as it grows, performs its functions, and divides.

DNA Replication

The process occurring in the S phase where an existing DNA produces an identical copy of itself using a semi-conservative method.

Mitosis

A type of cell division where a somatic cell divides to produce two new cells with identical genetic material.

Prophase

The phase of mitosis where chromatin condenses into chromosomes, the nucleolus disintegrates, and the mitotic spindle starts to form.

Metaphase

The phase of mitosis where chromosomes align at the center of the cell along the metaphase plate.

Anaphase

The phase of mitosis where the mitotic spindle pulls and separates sister chromatids toward opposite poles.

Telophase

The phase of mitosis where daughter chromatids decondense and two new nuclei form.

Cytokinesis

The division of the cytoplasm, marked by a cleavage furrow in animals or a cell plate in plants.

Meiosis

A reductional cell division process that produces four daughter cells (gametes) with half the original chromosome number.

Crossing Over

The exchange of segments between non-sister chromatids of homologous chromosomes during Prophase I to enhance genetic diversity.

Synapsis

The pairing of homologous chromosomes during Prophase I.

Nondisjunction

The failure of chromosomes or chromatids to separate properly during cell division, resulting in an abnormal amount of DNA.

Aneuploidy

A condition where the cell has an abnormal number of individual chromosomes.

Polyploidy

A condition where the cell has an abnormal number of complete sets of chromosomes.

Down Syndrome

A disorder caused by trisomy $21$, characterized by distinct facial characteristics.

Diffusion

The passive movement of molecules in a solvent from an area of higher solute concentration to lower concentration until dynamic equilibrium.

Osmosis

The diffusion of water across a selectively permeable membrane from high water concentration to lower water concentration.

Isotonic Solution

A solution where the solute concentration is equal inside and outside the cell, resulting in no net water movement.

Hypotonic Solution

A solution with a lower solute concentration than the cell, causing the cell to swell or burst.

Hypertonic Solution

A solution with a higher solute concentration than the cell, causing animal cells to shrink or shrivel.

Active Transport

A transport mechanism moving molecules against their concentration gradient with the expenditure of energy (ATP).

Sodium-Potassium Pump

An active transport mechanism that moves sodium ions ($Na^+$) out of the cell and potassium ions ($K^+$) into the cell.

Endocytosis

A bulk transport process where cells intake external materials by engulfing them with the cell membrane.

Phagocytosis

A form of endocytosis where the cell engulfs large particles by wrapping pseudopodia around them.

Exocytosis

A bulk transport process where cells expel materials by fusing a vesicle with the cell membrane.

Carbohydrates

Biomolecules whose primary function is to provide quick energy; their monomer is the monosaccharide.

Proteins

Biomolecules used to build and repair body tissues, composed of amino acid monomers.

Lipids

Biomolecules that store long-term energy and insulate the body, composed of fatty acids and glycerol.

Nucleic Acids

Biomolecules that store and transmit genetic information, composed of nucleotide monomers.

Enzyme

A protein biomolecule that speeds up metabolic reactions, consisting of an apoenzyme, a cofactor/coenzyme, and an active site.

Oxidation

A chemical reaction involving the loss of electrons.

Reduction

A chemical reaction involving the gain of electrons.