LIFSCI 7C XL - PEQ Week 1 Questions And Answers

((Given image)) A stem cell is fate determined once it has received the Self Renewal signal. As result, which genes are newly expressed? (Check all that apply) - -ID genes -DIV genes -DET genes ((Given)) Shown here are four ligands (M, H, K, and L) and their corresponding receptors along with three genes (U, V, and W) whose activity the receptor controls through signal transduction. The arrows indicate gene activation, the T-bars indicate gene repression. If either U or V is required to activate W, which ligand (or ligands) result in W being active? (Select all that apply.) - -Ligand M -Ligand K -Ligand H A cell in a chick embryo is tested to determine whether it is a stem cell of some kind. These tests find: 1. The SR receptor is present 2. DIV genes are on 3. The DIFF (skin) genes are blocked 4. TF of the neural pathway is in the cytoplasm 5. Transducer 2 of the skin pathway is not phosphorylated ((Given)) Based on these results, the transcription factor of the Skin pathway is in the cytoplasm. True or False? - True Figure 9.15 shows how normal signaling works with a Ras protein acting downstream of a receptor kinase. You examine a cell line in which Ras is always activated even in the absence of a signaling molecule. This causes constant activation of the kinases in the MAP kinase pathway. Which of the following conditions would be MOST likely to turn off this abnormally active signaling pathway? -The addition of a drug that prevents the final kinase from interacting with its target protein in the nucleus If a mutation occurred in the cadherin gene so that the cytoplasmic domain no longer attached to the cytoskeleton, which of the following would occur? - Cadherins in desmosomes would no longer be anchored to intermediate filaments In many cells, the adhesion to the extracellular matrix through integrins causes the activation of kinases in the cytoplasm. This suggests that: - Integrins promote the activation of signal-transduction pathways Macrophage cells undergo a process called phagocytosis in which material is brought into a cell in the form of membrane vesicles and then transported along microtubules toward the cell center. Assuming that the centrosome is near the cell center, you can predict that these vesicles are moving to the _____ end of microtubules using the motor protein _____. - Minus end; dynein Phosphatases are a family of enzymes that remove phosphate groups from specific proteins; these phosphate groups had been added to the proteins by protein kinases. Vanadate is an inhibitor of phosphatases in eukaryotic cells. What effect would vanadate have on the response of cells to signals received by receptor kinases? - The response of the cell would last longer than it normally would. Suppose there is a mutation in a laminin-binding integrin gene that causes a loss of function in the cytoplasmic domains of the integrin. Which of the following would you expect to observe as a result of this mutation? - The integrin would be unable to signal the cytoplasm when it had bound to laminin Vascular endothelial growth factor (abbreviated VEGF and pronounced "Veg-F") is a peptide signaling molecule related to platelet-derived growth factor. VEGF is important in the formation of the circulatory system because its signaling pathway causes the formation of blood vessels in developing embryos during normal development. Tumors also produce and secrete VEGF, causing the formation of new blood vessels that supply these tumors. Given what you know about the different kinds of cell signaling and VEGF, which one of the following statements is TRUE? - VEGF is a paracrine signaling molecule because it binds to receptors on cells at the site where new blood vessels are needed