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17 Cards in this Set
- Front
- Back
First and Second messengers |
-first: ligand binds a cell surface receptor in plasma membrane -second: acts in the cytoplasm |
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G - proteins |
-link between 1st and 2nd messenger -complex coupled to membrane receptor -activated when ligand binds to receptor at membrane surface |
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Amplification |
-magnifies effect of signal on target cell -small number of signal molecules bind to membrane receptors -leads to thousands of second messengers in cell |
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How does phosphorylation of proteins produce a cellular response? |
-P of enzymes, structural proteins, transcription factors -influence structure and function of cell -increase energy production |
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Types of cell communication |
1. direct inercellular 2. contact - dependent 3. autocrine 4. paracrine 5. endocrine |
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How can differential gene regulation affect the cellular response? |
-differential expression of receptor or have a lot of it or have a little -two receptors with diff. affinities for the signal -different intracellular signal transduction proteins -expression of proteins controlled by signal transduction pathways varies |
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Indirect signaling |
-release of chemical messenger from signaling cell
-transport of messenger through extracellular environment of target cell -communication of signal to target cell |
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chemical messengers |
six classes: -amino acids/proteins -steroids -amines -lipids -purines -gases |
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Growth hormone |
direct metabolic effects indirect effects via IGf's on somatic growth |
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How does cell communication influence and coordinate the development of a complex, multicellular organism? |
-genomes and proteomes -metamorphosis -secretion of thyroid hormone increases during metamorphosis |
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Frog - stages of metamorphosis |
Tadpole - gills + skin for respiration, tail fin Early - hindlimbs grow Froglet - terrestrial lungs + legs, frontal eyes |
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Cells lost vs. cells gained during frog metamorphosis |
Gained: limbs - bone, muscle, connective tissue, blood vessels Lost: tail - notochord, muscle, connective tissue, blood vessel Trunk - little change |
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How does the thyroid hormone work? |
-gland releases hormone -travels through blood - transported across cell membrane -binds to thyroid hormone receptor |
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What happens in the nucleus after thyroid protein binds to receptor? |
In nucleus: hormone-receptor complex becomes a transcription factor and activates gene expression |
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How do the legs of frogs grow? |
-mitosis -cell differentiation - specialization of cells, produce new proteins |
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How is the tail lost in tadpoles? |
Transcription factors (new proteins) trigger apoptosis -cells die and tail is reabsorbed into the frog |
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Transcription factor |
Ex: target cells with Thyroid hormone have receptor - hormone receptor complex = transcription factor -Change gene expression allowing cells to become specialized - depends on concentration, receptor, development |