Terms : Hide Images
| 9025303879 | homeostasis | steady internal state/maintenance of internal balance |  | 0 |
| 9025303880 | cells communicate directly via... | cell junctions | 1 | |
| 9025303881 | cells become different because _________ varies among cells. | gene expression | 2 | |
| 9025303882 | what is the major factor that influences which genes will be expressed? | environment | 3 | |
| 9025303883 | what types of signals can the cell sense? | chemical and physical | 4 | |
| 9025303884 | where do external signals come from? | biological sources (pathogen, bee sting), physical sources (light, heat), and other cells | 5 | |
| 9025303885 | juxtacrine signaling | signaling between cells in direct contact with each other |  | 6 |
| 9025303886 | gap junctions | in animal cells, these junctions allow ions and small molecules to pass quickly |  | 7 |
| 9025303887 | plasmodesmata | in plant cells, these are tunnels of cytoplasm between cells that allow movement of ions, amino acids, sugars, small proteins, and microRNA |  | 8 |
| 9025303888 | synaptic signaling | local electrochemical signaling occurring between nerve cells or nerve and muscle cells |  | 9 |
| 9025303889 | neurotransmitters | short-lived chemical signals that play a key role in synaptic signaling |  | 10 |
| 9025303890 | paracrine signaling | local communication; cells secrete substances that affect only nearby cells, like growth factors during early animal development |  | 11 |
| 9025303891 | endocrine signaling | long-distance communication; distributes signals throughout a multicellular organism (hormones) |  | 12 |
| 9025303892 | signal transduction pathway | series of steps by which a signal on a cell's surface is converted to a specific cellular response |  | 13 |
| 9025303893 | three stages of cell signaling | reception, transduction, response | 14 | |
| 9025303894 | step 1 of cell signaling: reception | a ligand from outside the cell binds to a receptor protein and the receptor changes shape | 15 | |
| 9025303895 | step 2 of cell signaling: transduction | series of molecule interactions that relay signals from receptor to target molecule, typically within the cell | 16 | |
| 9025303896 | step 3 of cell signaling: response | the specific cellular response to the signal molecule, usually transcription or cytoplasmic activities | 17 | |
| 9025303897 | ligand | signaling molecule | 18 | |
| 9025303898 | location of receptors | within the cell and on the plasma membrane | 19 | |
| 9025303899 | intracellular receptors | inside the cell; found in the cytoplasm or nucleus. the ligand must be hydrophobic/nonpolar/very small |  | 20 |
| 9025303900 | membrane receptors | anchored to the cell membrane. the ligand is water-soluble/hydrophilic/polar/large |  | 21 |
| 9025303901 | second messengers | molecules inside the cell that relay signals from the receptor to the target molecule | 22 | |
| 9025303902 | protein kinase | enzyme that phosphorylates and activates proteins at the next level | 23 | |
| 9025303903 | phosphorylation | the addition of a phosphate group, usually to active a molecule or transfer energy | 24 | |
| 9025303904 | phosphorylation cascade | a reaction that enhances and amplifies a signal |  | 25 |
| 9025303905 | apoptosis | controlled cell suicide, where the cell is systematically dismantled and digested, protecting neighboring cells from damage |  | 26 |
| 9025303906 | autocrine signaling | signals diffuse from one part of a cell to another part of the same cell |  | 27 |
| 9025303907 | sequence of a signal transduction pathway | signal (1st messenger) >>> receptor >>> proteins or other 2nd messengers >>> cellular responses | 28 | |
| 9025303908 | if a ligand is HYDROPHOBIC, what type of receptor will it bind to? | intracellular | 29 | |
| 9025303909 | if a ligand is HYDROPHILIC, what type of receptor will it bind to? | membrane | 30 | |
| 9025303910 | when a ligand binds to a receptor, what happens to the receptor? | it changes shape, initiating some sort of response | 31 | |
| 9025303911 | receptor proteins | molecules with binding sites for signaling molecules (ligands) | 32 | |
| 9025303912 | gated ion channel receptors | transmembrane protein with a gated channel that opens and closes in response to a specific signal; when open, a specific ion can pass through |  | 33 |
| 9025303913 | ligand-gated ion receptor | a ligand, or molecular signal, triggers the channel to open/close to allow an ion to pass |  | 34 |
| 9025303914 | voltage-gated ion receptor | open or close in response to voltage differences across a membrane |  | 35 |
| 9025303915 | typical ligand-gated ion sequence | signal received >>> ligand binds to receptor >>> receptor changes shape >>> channel opens and ions pass >>> ions initiate chemical response inside cell >>> ligand detaches from receptor and deactivates channel | 36 | |
| 9025303916 | what can cause a ligand to detach from a receptor? | ligand can be broken down by an enzyme, binding site can be blocked by an allosteric ligand, or the ion passage can be obstructed by a channel blocker | 37 | |
| 9025303917 | example of a ligand-gated ion channel | an active neuron releases acetylcholine (Ach) into synapse >>> Ach binds to ligand-gated receptor molecule of next neuron >>> receptor molecules open >>> Na+ enters cell >>> inside of cell becomes more positive >>> change in voltage initiates a nerve impulse | 38 | |
| 9025303918 | example of a voltage-gated ion channel | after Ach binds and Na+ enters the cytoplasm, the voltage inside the neuron becomes more positive. if strong enough, voltage-gated ion channels for Na+ and then K+ will open, allowing the impulse to travel along the neuron. | 39 | |
| 9025303919 | G-protein coupled receptor (GPCR) | a transmembrane protein that activates a G protein, which in turn activates another membrane protein, which triggers a cell response or activates a second messenger |  | 40 |
| 9025303920 | why is a G-protein receptor called that? | it has a GTP or a GDP attached to it instead of ATP or ADP (the difference is guanine instead of adenine) | 41 | |
| 9025303921 | typical G-protein coupled receptor sequence | ligand binds to receptor and it changes shape >>> receptor uses GTP to activate G protein >>> G protein binds to effector protein >>> effector is activated >>> effector initiates response >>> GTP is converted to GDP >>> receptor is deactivated | 42 | |
| 9025303922 | protein kinase receptors | transmembrane protein that is a kinase (enzyme that adds phosphate groups to a protein) |  | 43 |
| 9025303923 | protein kinase receptors are most important in... | cell reproduction and regulation | 44 | |
| 9025303924 | G-protein coupled receptors are most important in... | most things - it is the largest family of signal receptors and includes vision, taste, airborne signals, hormones, neurotransmitters, immune system | 45 | |
| 9025303925 | types of cell surface receptors | ion channel receptors, G-protein coupled receptors, and protein kinase receptors | 46 | |
| 9025303926 | ion channel receptors are most important in... | muscle contraction and nerve impulses | 47 | |
| 9025303927 | best understood protein kinase receptor | receptor tyrosine kinase (RTK) | 48 | |
| 9025303928 | typical protein kinase receptor sequence | ligand binds to receptor >>> receptor forms a dimer with another receptor >>> the receptors phosphorylate each other and activates the complex >>> relay protein attaches to receptor and is phosphorylated >>> relay proteins are released >>> relay proteins activate cellular response | 49 | |
| 9025303929 | how is a protein kinase receptor deactivated? | dephosphorylation of kinases OR when the membrane folds and encircles the receptor protein in a vesicle (endocytosis) | 50 | |
| 9025303930 | examples of protein kinase receptor signaling pathways | insulin signaling and mitogen-activated protein kinases (MAPK) | 51 | |
| 9025303931 | examples of hydrophobic chemical messengers for intracellular/cytoplasmic receptors | steroid hormones (testosterone, estrogen), thyroid hormones, nitric oxide gas (NO), second messengers | 52 | |
| 9025303932 | typical intracellular receptor signaling pathway | ligand enters cytoplasm >>> ligand binds to and activates receptor in cytoplasm or nucleus >>> complex acts as a transcription factor, binding to DNA and affecting gene expression | 53 | |
| 9025303933 | how is an intracellular receptor signaling pathway deactivated? | ligand or receptor proteins are enzymatically degraded | 54 | |
| 9025303934 | second messenger | molecules that relay a signal from the inside face of the receptor protein to other molecules that may initiate a cellular response or may act as additional second messengers | 55 | |
| 9025303935 | characteristics of a second messenger | small, nonprotein, and hydrophilic/hydrophobic/gaseous | 56 | |
| 9025303936 | cascade effect/signaling cascade | a series of enzymatic reactions where a small number of enzymes can activate more and more to initiate a large-scale response |  | 57 |
| 9025303937 | scaffold proteins | improve efficiency of a signaling cascade by holding enzymes involved in close proximity - keeps members of one signaling cascade isolated from others |  | 58 |
| 9025303938 | protein phosphatase | dephosphorylates a substrate (removes a phosphate group to deactivate it) | 59 | |
| 9025303939 | characteristics of signaling pathways | characterized by a signal, transduction, and a response. highly specific and regulated. one signal molecule can cause a cascade effect, releasing thousands inside the cell. these pathways evolved millions of years ago in a common ancestor. | 60 | |
| 9025303940 | advantages of signaling pathways | amplification (widespread), control (very accurate), and multiplicity (a single signaling molecule can activate many different pathways) | 61 |
