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| 93033593 | Signal transduction pathway | A mechanism linking a mechanical or chemical stimulus to a specific cellular response | |
| 93033594 | Local regulators | A secreted molecule that influences cells in the vicinity | |
| 93033595 | Hormones | In multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body to change their functioning | |
| 93033596 | Transduction | A type of horizontal gene transfer in which phages (viruses) carry bacterial DNA from the host cell to another. | |
| 93033597 | Response | (1) In cellular communication, the change in a specific cellular activity brought about by a transduced signal from outside the cell. (2) In homeostasis, a physiological activity that helps return a variable to a set point. | |
| 93033598 | Ligand | A molecule that binds specifically to another molecule, usually a larger one | |
| 93033601 | Receptor tyrosine kinases | A receptor protein in the plasma membrane. Often respond to the binding of a signaling molecule by dimerizing then phosphorylating a tyrosine on the cytoplasmic portion of the other receptor in the dimer. | |
| 93033602 | Ligand-gated ion channel | A protein pore in cellular membranes that opens or closes in response to a signaling chemical (its ligand), allowing or blocking the flow of specific ions. | |
| 93033603 | Protein kinase | An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein. | |
| 93033604 | Protein phosphatase | An enzyme that removes phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase. | |
| 93033605 | Second messengers | A small, nonprotein, water-soluble molecule or ion, such as a calcium ion (Ca2+) or cyclic AMP, that relays a signal to a cell's interior in response to a signaling molecule bound by a signal receptor protein. | |
| 93033606 | Cyclic AMP or cAMP | Cyclic adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. Its also a regulator of some bacterial operons. | |
| 93033607 | Adenylyl cyclase | An enzyme that converts ATP to to cyclic AMP in response to a signal | |
| 93033608 | Inositol triphosphate (IP3) | A second messenger that functions as an intermediate between certain nonsteriod hormones and a third messenger, a rise in cytoplasmic Ca2+ concentration. | |
| 93033609 | Diacylglycerol (DAG) | A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane | |
| 93033610 | Scaffolding proteins | A type of large relay protein to which several other realy proteins are stimultaneously attached, increasing the efficiency of signal transduction | |
| 93033611 | Apoptosis | A program of controlled cell suicide, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die. | |
| 93033612 | Cell division | The reproduction of cells | |
| 93033613 | Cell cycle | An ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two; the eukaryotic cell cycle is composed of interphase (including G1, S, and G2 subphases) and M phase (including mitosis and cytokinesis) | |
| 93033614 | Genome | The genetic material of an organism or virus; the complete compliment of an organism's or virus's genes along with its noncoding nucleic acid sequences. | |
| 93033615 | Chromosomes | A structure carrying genetic material, found in the nucleus of eukaryotic cells. Each chromosome consists of one very ong DNA molecule and associated proteins. | |
| 93033616 | Somatic cell | Any cell in a multicellular organism except a sperm or egg cell. | |
| 93033617 | Gamete | A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote | |
| 93033618 | Chromatin | The complex of DNA and proteins that makes up a eukaryotic chromosome. When the cell is not dividing, chromatin exists in its dispersed form, as a mass of very long, thin fibers that are not visible with a light microscope. | |
| 93033619 | Sister chromatid | Either of two copies of a duplicated chromosome attached to each other by proteins at the centromere and, sometimes, along the arms. While joined, two sister chromatids make up one chromosome; chromatids are eventually seperated during mitosis or meiosis II. | |
| 93033620 | Centromere | The specialized region of the chromosome where two sister chromatids are most closely attached. | |
| 93033621 | Mitosis | A process of nuclear division of eukaryotic cells conventionally divided into 5 stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by allocating replicated chromosomes equally to each of the daughter nuclei. | |
| 93033622 | Cytokinesis | The division of the cytoplasm to form teo seperate daughter cells immediatly after mitosis, meiosis I, or meiosis II | |
| 93033623 | Meiosis | A modified form of cell division in sexually reproducing organisms consisting of two rounds of cell division but only one round of DNA replication. It results in cells with half the number of chromosome sets as the original cell. | |
| 93033624 | Mitotic (M) phase | The phase of the cell cycle that includes mitosis and cytokinesis | |
| 93033625 | Interphase | The period in the cell cycle when the cell is not dividing. During interphase, cellular metabolic activity is high, chromosomes and organelles are duplicated, and cell size may increase. Interphase accounts for 90% of the cell cycle. | |
| 93033626 | G1 phase | The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins | |
| 93033627 | S phase | The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. | |
| 93033628 | G2 phase | The second gap, or growth phase, of the cell cycle, consisting of the portion of interphase after DNA synthesis begins. | |
| 93033629 | Prophase | The first stage of mitosis, in which the chromatin condenses, the mitotic spindle begins to form, and the nucleolus disappears, but the nucleus remains intact | |
| 93033630 | Prometaphase | the second stage of mitosis, in which descrete chromosomes consisting of identical sister chromatids appear, the nuclear envelope fragments, and the spindle microtubules attach to the kinetochores of the chromosomes. | |
| 93033631 | Metaphase | The third stage of mitosis, in which the spindle is complete and the chromosomes, attached to the microtubules at their kinetchores, are all aligned at the metaphase plate | |
| 93033632 | Anaphase | The fourth stage of mitosis, in which the chromatids of each chromosome have seperated and the daughter chromosomes are moving to the poles of the cell | |
| 93033633 | Telophase | The fifth and final phase of mitosis in which daughter nuclei are forming and cytokinesis has typically begun | |
| 93033634 | Mitotic spindle | An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis | |
| 93033635 | Centrosome | Structure present in the cytoplasm of animal cells, important during cell division; functions as a microtubule-organizing center. Has teo centrioles | |
| 93033636 | Aster | A radial array of short microtubules that extends from each centrosome toward the plasma membrane in a cell under going mitosis | |
| 93033637 | Kinetochore | A structure of proteins attached to the centromere that links each sister chromatid to the mitotic spindle | |
| 93033638 | Metaphase plate | An imaginary plane midway between the two poles of a cell in metaphase on which the centromeres of all the duplicated chromosomes are located | |
| 93033639 | Cleavage | (1) The process of cytokinesis in animal cells, chracterized by oinching of the plasma membrane. (2) The sucsession or rapid cell divisions without growth during early embryonic development that converts the zygote to a ball of cells. | |
| 93033640 | Cleavage furrow | The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate. | |
| 93033641 | Cell plate | A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis. | |
| 93033642 | Binary fission | A method of asexual reproduction by "division in half". In prokaryotes, bionary fission doesn't involve mitosis; but in single-celled eukaryotes that undergo binary fission, mitosis is a part of the process. | |
| 93033643 | Origin of replication | Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides. | |
| 93033644 | Cell cycle control system | A cyclically operating set of molecules in the eukaryotic cell that both triggers and coordinates key events in the cell cycle. | |
| 93033645 | Checkpoint | A control point in the cell cycle where stop and go-ahead signals can regulate the cycle. | |
| 93033646 | G0 phase | A nondividing state occupied by cells that have left the cell cycle. | |
| 93033647 | Cyclin | A cellular protein that occure in a cyclically fluctuating concentration and that plays an impotant role in regulating the cell cycle. | |
| 93033648 | Cyclin-dependent kinase (Cdk) | A protein kinase that is active only when attached to a particular cyclin | |
| 93033649 | Maturation-promoting factor (MPF) | A protein complex required for a cell to progress fom late interphase to mitosis. The active form consists of cyclin and a protein kinase | |
| 93033650 | Growth factor | (1) A protein that must be present in the extracellular environment (culture medium or animal body) for the growth and normal development of certian types of cells. (2) A local regulator that acts on nearby cells to stimulate cell proliferation differentiation | |
| 93033651 | Density-dependent inhibition | The phenomenon observed in normal animal cells that causes them to stop dividing when they come into contact with one another | |
| 93033652 | Anchorage dependence | The requirement that a cell must be attached to the substratum in order to divide | |
| 93033653 | Transformation | (1) The conversion of a normal animal cell to a cancerous cell. (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. | |
| 93033654 | Benign tumor | A mass of abnormal cells that remains at the site of the origin. | |
| 93033655 | Malignant tumor | A cancerous tumor that is invasive enough to impair the functions of one or more organs | |
| 93033656 | Metastasis | The spread of cancer cells to locations distant from their original site. | |
| 93090139 | G protein | A GTP-binding protein that relays signals from a plasma membrane signal receptor, know as a G-protein coupled receptor, to other signal transduction proteins inside the cell. | |
| 93090140 | G protein-coupled receptor | A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by acctivating a G protein. Also called a G protein-linked receptor. |
