If we knock out a gene, it can tell us something about how important that gene is or if other genes can compensate for its absence in a complex. To further establish the role of PSEN1 and PSEN2 in early onset Alzheimer's disease they are individually knocked out in mouse models. Knockout of PSEN1 leads to an embryonic lethal phenotype and dramatically reduced AB levels. However knockout of PSEN2 gives no obvious phenotype and essentially normal AB levels. Question 16) Which of the following hypotheses does this observation support? [10 Marks] a. Under normal circumstances y-secretase complexes contain equal ratios of PSEN1 and PSEN2 O b. O c. The knockout of PSEN1 and PSEN2 didn't work Under normal circumstances y-secretase complexes primarily contain PSEN2 rather than PSEN1 d. Under normal circumstances y-secretase complexes primarily contain PSEN1 rather than PSEN2 e. Under normal circumstances y-secretase complexes do not contain either PSEN1 or PSEN2

If we knock out a gene, it can tell us something about how important that gene is or if other genes can compensate for its absence in a complex. To further establish the role of PSEN1 and PSEN2 in early onset Alzheimer's disease they are individually knocked out in mouse models. Knockout of PSEN1 leads to an embryonic lethal phenotype and dramatically reduced AB levels. However knockout of PSEN2 gives no obvious phenotype and essentially normal AB levels. Question 16) Which of the following hypotheses does this observation support? [10 Marks] a. Under normal circumstances y-secretase complexes contain equal ratios of PSEN1 and PSEN2 O b. O c. The knockout of PSEN1 and PSEN2 didn't work Under normal circumstances y-secretase complexes primarily contain PSEN2 rather than PSEN1 d. Under normal circumstances y-secretase complexes primarily contain PSEN1 rather than PSEN2 e. Under normal circumstances y-secretase complexes do not contain either PSEN1 or PSEN2

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Description: If we knock out a gene, it can tell us something about how important that gene isor if other genes can compensate for its absence in a complex. To furtherestablish the role of PSEN1 and PSEN2 in early onset Alzheimer's disease theyare individually k

Biology Today and Tomorrow without Physiology (MindTap Course List)

5th Edition

ISBN:9781305117396

Author:Cecie Starr, Christine Evers, Lisa Starr

Publisher:Cecie Starr, Christine Evers, Lisa Starr

Chapter10: Biotechnology

Section: Chapter Questions

Problem 4DID

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Recently, scientists constructed a transgene that expresses a mutant form of Drosophila histone H3 inwhich lysine 27 in the histone tail was changed to methionine (H3K27M). Expression of the H3K27Mtransgene results in aberrant development of fruit fliesbecause of inappropriate expression of many differentgenes. Explain this finding.
Researchers know that Fru-M controls male sexualbehavior in Drosophila because inappropriate Fru-Mexpression in females causes them to behave likemales: Such females display male behaviors that areoriented toward other females.a. Describe a fru mutation that could cause the expression of Fru-M in females.b. Describe a transgene construct that scientistscould generate and insert into Drosophila femalesthat would have the same effect as the mutant youdescribed in (a).
The three homeodomain proteins Abd-B, Abd-A, andUbx are encoded by genes within the Bithorax complexof Drosophila. In wild-type embryos, the Abd-B gene isexpressed in the posterior abdominal segments, Abd-Ain the middle abdominal segments, and Ubx in the anterior abdominal and posterior thoracic segments. Whenthe Abd-B gene is deleted, Abd-A is expressed in both themiddle and the posterior abdominal segments. WhenAbd-A is deleted, Ubx is expressed in the posterior thoraxand in the anterior and middle abdominal segments.When Ubx is deleted, the patterns of Abd-A and Abd-Bexpression are unchanged from wild type. When bothAbd-A and Abd-B are deleted, Ubx is expressed in all segments from the posterior thorax to the posterior end ofthe embryo. Explain these observations, taking into consideration the fact that the gap genes control the initialexpression patterns of the homeotic genes
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