Genetic expression leading to different cell types in multicellular organism
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| 604573003 | Fertilized egg | zygote | 0 | |
| 604573004 | How are cells organized? What does this mean for any developmental program? | cells->tissues->organs->organ systems->whole organism; development must include producing cells of different types that form higher-level structures arranged in a particular way in 3-D | 1 | |
| 604573005 | 3 step process of zygote to organism: | 1. cell division 2. cell differentiation 3. morphogenesis | 2 | |
| 604573006 | Cell differentiation | process by which cells become specialized in structure and function, and are organized into tissues and organs; occurs during embryonic development | 3 | |
| 604573007 | Morphogenesis | physical processes that give an organism its shape | 4 | |
| 604573008 | Differential gene expression: liver vs. lens cell | -each cell has particular mix of specific activators -these activators turn on the collection of genes whose products are required in the cell | 5 | |
| 604573009 | How do different sets of activators come to be present in the two cells? | material placed in egg by mother triggers sequential program of gene regulation that occurs as cells divide; this program makes the cells different from each other | 6 | |
| 604573010 | What generates the 1st differences among cells in an early embryo? | specific genes expressed in any particular cell of a developing organism determines its path | 7 | |
| 604573011 | What controls the differentiation of all the various cell types as development proceeds? | 1. cytoplasmic determinants 2. surrounding environment | 8 | |
| 604573012 | Cytoplasmic determinants-definition: | -maternal substances in the egg that influence course of early development -after fertilization, early mitotic divisions spread zygote's cytoplasm into separate cells -nuclei of these cells are thus exposed to different cytoplasmic determinants | 9 | |
| 604573013 | Role of cytoplasmic determinants: | the combo of cytoplasmic determinants in a cell helps it determine its developmental fate by regulation expression of gene's during course of cell differentiation | 10 | |
| 604573014 | Examples of environmental factors of cell: | -signals impinging on an embryonic cell from other embryonic cells nearby -contact with cell-surface molecules on neighboring cells -binding of growth factors secreted by neighboring cells | 11 | |
| 604573015 | Induction-definition: | caused by signals in cell's environment; process in which signals cause changes in target cells | 12 | |
| 604573016 | Describe induction: | 1. signaling molecules cause changes in a cell's gene expression 2. leads to observable cellular changes 3. these changes send said cell down specific developmental path | 13 | |
| 604573017 | What do interactions between embryonic cells do? | help induce differentiation of many specialized cell types making up a new organism | 14 | |
| 604573018 | Determination-definition: | events leading to observable differentiation of a cell; marked by expression of genes for tissue-specific proteins (ie. mRNA) | 15 | |
| 604573019 | Transcription-define: | principle regulatory point for maintaining appropriate gene expression in a fully differentiated cell | 16 | |
| 604573020 | How did scientists identify "master regulatory genes?" | -researchers focused on muscle cell determination -grew myoblasts in culture -isolated different genes from myoblasts -caused each gene to be expressed in a separate embryonic precursor cell -looked for differentiation in myoblasts and muscle cells | 17 | |
| 604573021 | What does the study of muscle cells tell us about the molecular basis of determination? | determination is on the basis of expression of one or more master regulatory genes | 18 | |
| 604573022 | myoD-define: | master regulatory gene that encodes MyoD protein | 19 | |
| 604573023 | MyoD protein: | a transcription factor that binds to specific control elements in the enhancers of target genes; stimulates expression of myoD gene itself, perpetuating its effect in maintaining cell's differentiated state; can change fully differentiated nonmuscle cells into muscle cells | 20 | |
| 604573024 | Why can't MyoD change all kinds of fully differentiated cell into muscle cells? | activation of muscle-specific genes is not solely dependent on MyoD; combination of regulatory proteins is needed | 21 | |
| 604573025 | 2 big contributors to pattern formation: | 1. cytoplasmic determinants 2. inductive signals -contribute to development of spatial organization in which tissues and organs of organism are all in there characteristic places | 22 | |
| 604573026 | Pattern formation: | -in animals, begins in early embryo -before tissues/organs of bilaterally symmetrical animal appear, relative positions of animal's head, tail, right & left sides, back and front are set up | 23 | |
| 604573027 | Positional information: | -molecular cues that control pattern formation provided by cytoplasmic determinants and inductive signals | 24 | |
| 604573028 | What did the study of Drosophila development show? | -genes control development -understanding of key roles molecules play in defining position/differentiation | 25 | |
| 604573029 | Drosophila development from egg to larva: | 1. egg is surrounded by nurse & follicle cells 2. nurse cells shrink as they supply nutrients and mRNAs to developing egg (which grows larger); mature egg fills egg shell that is secreted by follicle cells 3. egg is fertilized within mother and then laid 4. embryonic development forms a larva 5. larva goes through three stages, ending in cocoon formation within which larva metamorphoses into adult | 26 | |
| 604573030 | Who was Edward B. Lewis? | American biologist; research supplied evidence that genes direct developmental processes | 27 | |
| 604573031 | Homeotic genes: | discovered by Lewis, genes that control pattern formation in the late embryo, larva & adult; | 28 | |
| 604573032 | Embryonic lethals: | mutations with phenotypes causing death at embryonic or larval stage; caused problem in research bc could not bread organisms for study bc did not reproduce | 29 | |
| 604573033 | Maternal effect gene: | gene that (when mutant in the mother) results in a mutant phenotype in the offspring | 30 | |
| 604573034 | Why are maternal effect genes also called egg-polarity genes? | because they control the orientation (polarity) of the egg and consequently of the fly | 31 | |
| 604573035 | Bicoid: | gene that means two-tailed; embryo whose mother has 2 mutant alleles of the bicoid gene will lack the front half of its body and will instead have to back ends | 32 | |
| 604573036 | what is the morphogen gradient hypothesis? what does the bicoid study have to do with it? | gradients of morphogens establish an embryo's axes and other features of its forms; bicoid protein specifies fly's anterior end | 33 |
