BICD 130 wi 07 FINAL

BICD 130 wi 07 FINAL - BICD 130 Embryos, Genes, and...

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BICD 130 — Embryos, Genes, and Development Winter 2007 Final Exam (Five parts, 200 points total) KEY ______________________________________________________ Please PRINT your name here PLEASE WRITE YOUR ANSWERS IN INK Part I (44 pts.)_________________________ Part II (70 pts.)________________________ Part III (35 pts.)________________________ Part IV (30 pts.)________________________ Part V (21 pts.)________________________ EXAM TIP: Be sure to read the ENTIRE question carefully, and let the question’s point value guide you as to how in-depth your answer should be.
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I. (44 pts.) 1. (18 pts.) (a) Describe in detail how cadherins bring about cell-cell adhesion. Include in your answer the protein domains and the molecular interactions required for proper cadherin function. Use a diagram to illustrate your answer. -Diagram (3 points) (-1 point if diagram or explanation does not show/indicate which domains are intracellular, extracellular, etc.) -Has an intracellular domain with phosphorylation sites and a binding site to catenin molecules (1 pt) which connect the cadherin to the actin cytoskeleton. (1 pt) -Has a transmembrane domain. (1 pt) -Has several extracellular domains including one with a Ca2+ binding site (1 pt) and an adhesive recognition site. (1pt) -cadherins are calcium-dependent. (1 pt) -when Ca2+ binds to Ca2+ binding site it causes a conformational change to expose the adhesive recognition site so that the cadherin of one cell can bind to the cadherin of another cell. (1pt) (b) Name two types of cadherin molecules, the developmental processes in which they are involved, and the cell types that express them. (1 point each for naming the class, 1 point each for naming the developmental process and the cells expressing them) Any two of the following: -E-cadherin: presumptive epidermis during neurulation, endoderm during neurulation, oocyte/posterior egg chamber during Drosophila oogenesis. -P-cadherin: placental/trophoblast cells during embryo implantation -N-cadherin: presumptive neural tube during neurulation; presumptive neural crest during neurulation, mesoderm cells during gastrulation, Drosophila cone cells in eye development (soap bubbles) -EP-cadherin/C-cadherin: blastomeres of Xenopus embryo during gastrulation -Protocadherin: Xenopus dorsal mesoderm undergoing convergent extension during gastrulation. (c) Name and describe the types of cell adhesion molecule (CAM) interaction. (2 points each) -homophilic/homotypic: when binding of the CAM of one cell to CAM of another cell is of the same type. -heterophilic/heterotypic: when binding of the CAM of one cell to CAM of another cell is of different types. -0.5 points if not mentioned anywhere that interacting CAMs are on different cells -0.5 points if “-philic” or “-typic” incorrect or missing
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2. (8 pts.) An XY mouse carries a mutation that inactivates the DNA-binding domain of the testosterone receptor (remember that testosterone is a steroid hormone, and so uses a member of the nuclear receptor family of transcription factors to carry the signal to the
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BICD 130 wi 07 FINAL - BICD 130 Embryos, Genes, and...

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