3.7: Key Terms
- Page ID
- 108192
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| Words (or words that have the same definition) | The definition is case sensitive | (Optional) Image to display with the definition [Not displayed in Glossary, only in pop-up on pages] | (Optional) Caption for Image | (Optional) External or Internal Link | (Optional) Source for Definition |
|---|---|---|---|---|---|
| (Eg. "Genetic, Hereditary, DNA ...") | (Eg. "Relating to genes or heredity") |  | The infamous double helix | https://bio.libretexts.org/ | CC-BY-SA; Delmar Larsen |
| Word(s) | Definition | Image | Caption | Link | Source |
|---|---|---|---|---|---|
| active transport | form of transport across the cell membrane that requires input of cellular energy | ||||
| amphipathic | describes a molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility | ||||
| anaphase | third stage of mitosis (and meiosis), during which sister chromatids separate into two new nuclear regions of a dividing cell | ||||
| anticodon | consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule | ||||
| autolysis | breakdown of cells by their own enzymatic action | ||||
| autophagy | lysosomal breakdown of a cell’s own components | ||||
| cell cycle | life cycle of a single cell, from its birth until its division into two new daughter cells | ||||
| cell membrane | membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as plasma membrane | ||||
| centriole | small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division | ||||
| centromere | region of attachment for two sister chromatids | ||||
| centrosome | cellular structure that organizes microtubules during cell division | ||||
| channel protein | membrane-spanning protein that has an inner pore which allows the passage of one or more substances | ||||
| checkpoint | progress point in the cell cycle during which certain conditions must be met in order for the cell to proceed to a subsequence phase | ||||
| chromatin | substance consisting of DNA and associated proteins | ||||
| chromosome | condensed version of chromatin | ||||
| cilia | small appendage on certain cells formed by microtubules and modified for movement of materials across the cellular surface | ||||
| cleavage furrow | contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves | ||||
| codon | consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid | ||||
| concentration gradient | difference in the concentration of a substance between two regions | ||||
| cyclin | one of a group of proteins that function in the progression of the cell cycle | ||||
| cyclin-dependent kinase (CDK) | one of a group of enzymes associated with cyclins that help them perform their functions | ||||
| cytokinesis | final stage in cell division, where the cytoplasm divides to form two separate daughter cells | ||||
| cytoplasm | internal material between the cell membrane and nucleus of a cell, mainly consisting of a water-based fluid called cytosol, within which are all the other organelles and cellular solute and suspended materials | ||||
| cytoskeleton | “skeleton” of a cell; formed by rod-like proteins that support the cell’s shape and provide, among other functions, locomotive abilities | ||||
| cytosol | clear, semi-fluid medium of the cytoplasm, made up mostly of water | ||||
| diffusion | movement of a substance from an area of higher concentration to one of lower concentration | ||||
| diploid | condition marked by the presence of a double complement of genetic material (two sets of chromosomes, one set inherited from each of two parents) | ||||
| DNA polymerase | enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication | ||||
| DNA replication | process of duplicating a molecule of DNA | ||||
| electrical gradient | difference in the electrical charge (potential) between two regions | ||||
| endocytosis | import of material into the cell by formation of a membrane-bound vesicle | ||||
| endoplasmic reticulum (ER) | cellular organelle that consists of interconnected membrane-bound tubules, which may or may not be associated with ribosomes (rough type or smooth type, respectively) | ||||
| exocytosis | export of a substance out of a cell by formation of a membrane-bound vesicle | ||||
| exon | one of the coding regions of an mRNA molecule that remain after splicing | ||||
| extracellular fluid (ECF) | fluid exterior to cells; includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body | ||||
| facilitated diffusion | diffusion of a substance with the aid of a membrane protein | ||||
| flagellum | appendage on certain cells formed by microtubules and modified for movement | ||||
| G0 phase | phase of the cell cycle, usually entered from the G1 phase; characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase | ||||
| G1 phase | first phase of the cell cycle, after a new cell is born | ||||
| G2 phase | third phase of the cell cycle, after the DNA synthesis phase | ||||
| gene | functional length of DNA that provides the genetic information necessary to build a protein | ||||
| gene expression | active interpretation of the information coded in a gene to produce a functional gene product | ||||
| genome | entire complement of an organism’s DNA; found within virtually every cell | ||||
| glycocalyx | coating of sugar molecules that surrounds the cell membrane | ||||
| glycoprotein | protein that has one or more carbohydrates attached | ||||
| Golgi apparatus | cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport | ||||
| helicase | enzyme that functions to separate the two DNA strands of a double helix during DNA replication | ||||
| histone | family of proteins that associate with DNA in the nucleus to form chromatin | ||||
| homologous | describes two copies of the same chromosome (not identical), one inherited from each parent | ||||
| hydrophilic | describes a substance or structure attracted to water | ||||
| hydrophobic | describes a substance or structure repelled by water | ||||
| hypertonic | describes a solution concentration that is higher than a reference concentration | ||||
| hypotonic | describes a solution concentration that is lower than a reference concentration | ||||
| integral protein | membrane-associated protein that spans the entire width of the lipid bilayer | ||||
| intermediate filament | type of cytoskeletal filament made of keratin, characterized by an intermediate thickness, and playing a role in resisting cellular tension | ||||
| interphase | entire life cycle of a cell, excluding mitosis | ||||
| interstitial fluid (IF) | fluid in the small spaces between cells not contained within blood vessels | ||||
| intracellular fluid (ICF) | fluid in the cytosol of cells | ||||
| intron | non-coding regions of a pre-mRNA transcript that may be removed during splicing | ||||
| isotonic | describes a solution concentration that is the same as a reference concentration | ||||
| kinetochore | region of a centromere where microtubules attach to a pair of sister chromatids | ||||
| ligand | molecule that binds with specificity to a specific receptor molecule | ||||
| lysosome | membrane-bound cellular organelle originating from the Golgi apparatus and containing digestive enzymes | ||||
| messenger RNA (mRNA) | nucleotide molecule that serves as an intermediate in the genetic code between DNA and protein | ||||
| metaphase | second stage of mitosis (and meiosis), characterized by the linear alignment of sister chromatids in the center of the cell | ||||
| metaphase plate | linear alignment of sister chromatids in the center of the cell, which takes place during metaphase | ||||
| microfilament | the thinnest of the cytoskeletal filaments; composed of actin subunits that function in muscle contraction and cellular structural support | ||||
| microtubule | the thickest of the cytoskeletal filaments, composed of tubulin subunits that function in cellular movement and structural support | ||||
| mitochondrion | one of the cellular organelles bound by a double lipid bilayer that function primarily in the production of cellular energy (ATP) | ||||
| mitosis | division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed | ||||
| mitotic phase | phase of the cell cycle in which a cell undergoes mitosis | ||||
| mitotic spindle | network of microtubules, originating from centrioles, that arranges and pulls apart chromosomes during mitosis | ||||
| multipotent | describes the condition of being able to differentiate into different types of cells within a given cell lineage or small number of lineages, such as a red blood cell or white blood cell | ||||
| mutation | change in the nucleotide sequence in a gene within a cell’s DNA | ||||
| nuclear envelope | membrane that surrounds the nucleus; consisting of a double lipid-bilayer | ||||
| nuclear pore | one of the small, protein-lined openings found scattered throughout the nuclear envelope | ||||
| nucleolus | small region of the nucleus that functions in ribosome synthesis | ||||
| nucleosome | unit of chromatin consisting of a DNA strand wrapped around histone proteins | ||||
| nucleus | cell’s central organelle; contains the cell’s DNA | ||||
| oligopotent | describes the condition of being more specialized than multipotency; the condition of being able to differentiate into one of a few possible cell types | ||||
| organelle | any of several different types of membrane-enclosed specialized structures in the cell that perform specific functions for the cell | ||||
| osmosis | diffusion of water molecules down their concentration gradient across a selectively permeable membrane | ||||
| passive transport | form of transport across the cell membrane that does not require input of cellular energy | ||||
| peripheral protein | membrane-associated protein that does not span the width of the lipid bilayer, but is attached peripherally to integral proteins, membrane lipids, or other components of the membrane | ||||
| peroxisome | membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances | ||||
| phagocytosis | endocytosis of large particles | ||||
| pinocytosis | endocytosis of fluid | ||||
| pluripotent | describes the condition of being able to differentiate into a large variety of cell types | ||||
| polypeptide | chain of amino acids linked by peptide bonds | ||||
| polyribosome | simultaneous translation of a single mRNA transcript by multiple ribosomes | ||||
| promoter | region of DNA that signals transcription to begin at that site within the gene | ||||
| prophase | first stage of mitosis (and meiosis), characterized by breakdown of the nuclear envelope and condensing of the chromatin to form chromosomes | ||||
| proteome | full complement of proteins produced by a cell (determined by the cell’s specific gene expression) | ||||
| reactive oxygen species (ROS) | a group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage | ||||
| receptor | protein molecule that contains a binding site for another specific molecule (called a ligand) | ||||
| receptor-mediated endocytosis | endocytosis of ligands attached to membrane-bound receptors | ||||
| ribosomal RNA (rRNA) | RNA that makes up the subunits of a ribosome | ||||
| ribosome | cellular organelle that functions in protein synthesis | ||||
| RNA polymerase | enzyme that unwinds DNA and then adds new nucleotides to a growing strand of RNA for the transcription phase of protein synthesis | ||||
| S phase | stage of the cell cycle during which DNA replication occurs | ||||
| selective permeability | feature of any barrier that allows certain substances to cross but excludes others | ||||
| sister chromatid | one of a pair of identical chromosomes, formed during DNA replication | ||||
| sodium-potassium pump | (also, Na+/K+ ATP-ase) membrane-embedded protein pump that uses ATP to move Na+ out of a cell and K+ into the cell | ||||
| somatic cell | all cells of the body excluding gamete cells | ||||
| spliceosome | complex of enzymes that serves to splice out the introns of a pre-mRNA transcript | ||||
| splicing | the process of modifying a pre-mRNA transcript by removing certain, typically non-coding, regions | ||||
| stem cell | cell that is oligo-, multi-, or pleuripotent that has the ability to produce additional stem cells rather than becoming further specialized | ||||
| telophase | final stage of mitosis (and meiosis), preceding cytokinesis, characterized by the formation of two new daughter nuclei | ||||
| totipotent | embryonic cells that have the ability to differentiate into any type of cell and organ in the body | ||||
| transcription | process of producing an mRNA molecule that is complementary to a particular gene of DNA | ||||
| transcription factor | one of the proteins that regulate the transcription of genes | ||||
| transfer RNA (tRNA) | molecules of RNA that serve to bring amino acids to a growing polypeptide strand and properly place them into the sequence | ||||
| translation | process of producing a protein from the nucleotide sequence code of an mRNA transcript | ||||
| triplet | consecutive sequence of three nucleotides on a DNA molecule that, when transcribed into an mRNA codon, corresponds to a particular amino acid | ||||
| unipotent | describes the condition of being committed to a single specialized cell type | ||||
| vesicle | membrane-bound structure that contains materials within or outside of the cell |