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anatomy CH3
Term/Definition
Term | Definition |
---|---|
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 |
G 0 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 |
messanger 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 cyytoskeletal 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 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 | 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 commited to a single specialized cell type |
vesicle | membrane-bound structure that contains materials within or outside of the cell |
homeostasis | a term used in biology that refers to a dynamic state of balance within parameters that are compatible with life |
cell recognition proteins | important group of proteins which serve to mark a cell's identity so that it can be recognized by other cells |
filtration | mechanism to passively transport materials between compartments; uses a hydrostatic pressure gradient that pushes fluid-and solutes within it-from a higher pressure area to a lower pressure area |
secondary active transport | the action of an active transport pump powers the passive transport of sodium ions by creating a concentration gradient; when active transport powers the trans port of another substance |
symporters | secondary active transporters that move two substances in the same direction |
antiporters | secondary active transport systems that transport substances in opposite directions |
endomembrane system | a set of three major organelles-endoplasmic reticulum, Golgi apparatus, and vesicles- working together to perform various cellular jobs, including the task of producing, packaging, and exporting certain cellular products |
rough endoplasmic reticulum (RER) | primary job is the synthesis and modification of proteins destined for the cell membrane or for export from the cell; its membrane is dotted with embedded granules-organelles called ribosomes, giving the RER a bumpy appearance |
smooth endoplasmic reticulum (SER) | main function is in the synthesis of lipids; sequesters and regulates the concentration of cellular Ca++; metabolizes some carbohydrates and performs a detoxification role, breaking down certain toxins; lacks the ribosomes of RER |
apoptosis | controlled cell death process |
oxidative stress | term used to describe damage to cellular components caused by reactive oxygen species (ROS) |
actin | a protein that forms chains; the primary component of microfilaments; important role during cell division, actin filaments work with myosin to create a cleavage furrow that eventually splits the cell down the middle, forming two new cells |
differentation | the process by which unspecialized cells become specialized to carry out distinct functions |