NAME: May 20th, 2009 Feinstein Grad Cell Bio Exam#3: Biol Cell Bio 2013/Feinstein/Old...آ 1...
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NAME:_______________ May 20th, 2009 Feinstein Grad Cell Bio Exam#3: Biol 714 Part II: 50pts A) 15pts. The data above suggests that the βgal+ neurons are choosing to express Class II ORs from their Class II promoters.
1) Design a simple experiment that would distinguish if the segregation of axons into two domains on the bulb reflects the neuronal lineage or Class of the OR.
2) Explain what your experiment would show.
B) 15pts Odorant receptors (ORs) provide some kind of homophilic code to axons. However, you don’t believe that ORs can homophilically bind to each other. (This should be formally tested as part of your experiment below.) Let’s say that you have identified CDH2 as the only accessory protein needed to read the structural code of the OR as depicted in the figure. Thus, the hypothesis is that CDH2 plus an OR gives rise to a homophilic code.
Design an in vitro (not in an animal) experiment to prove this hypothesis. Explain your experiment as to how you would interpret the results.
If I were to identify the cdh2 gene, which helped promote glomerular formation based on the identity of the OR, then
1) Why would mosaic analysis help me to study its function? (5pts) 2) Why would having the gene located on the X chromosome help me in my analysis
of the gene’s function. (5pts) 3) Unfortunately, the cdh2 gene is NOT on the X chromosome and the mouse dies
embryonically when a complete null allele is created in the genome. Design an in vivo (in the mouse) experiment that would help me understand how this gene operates. (10pts)
NAME:_______________ May 20th, 2009 Feinstein Grad Cell Bio Exam#3: Biol 714 Part III: 25pts Extra Credit (1pt per question) For TRUE (1pt) /FALSE (1/2pts) , If FALSE then you must give a short answer (1 sentence) as to why (1/2pts): Circle one.
1) NGF (nerve growth factor) is a Neurotrophic Neurotropic (circle one) factor because it acts to both allow for the proliferation of neurons and promote axon guidance.
2) Netrin is a Neurotrophic Neurotropic (circle one) factor because it acts to
promote axon guidance. 3) Odorant receptor proteins are GPCRs because they contain seven transmembrane
domains. (TRUE or FALSE). 4) All seven transmembrane domain proteins are GPCRs. (TRUE or FALSE). 5) Odorant receptors couple to Gproteins via the Galpha subunit. This interaction
catalyzes the release of the Gbetagamma subunits and the Galpha-GTP form is free to bind to Adenylate Cyclase (TRUE or FALSE).
6) Odorant binding to odorant receptors induce a conformational change to the seven transmembrane structure. (TRUE or FALSE).
7) Odorant binding to odorant receptors stabilize a conformational change to the seven transmembrane structure. (TRUE or FALSE).
8) During the process of ligand binding to the GPCR, a change in the 3rd transmembrane domain conformation relative to the rest of the molecule allows for the Galpha subunit to exchange GDP for GTP. (TRUE or FALSE).
9) Axonal fasciculation (axon-axon interactions) is what causes axons to project
together in the brain. (TRUE or FALSE).
10) Axons sense the path to grow by use of their leading edge, the growth cone. (TRUE or FALSE).
11) The primary role of integrins is to bind to the extracellular matrix proteins such as
collagen and fibronectin. (TRUE or FALSE).
12) The Ig superfamily of cell adhesion molecules is often referred to as IgCAM receptors. In class, knockouts of these receptors were shown to have dramatic effects on axon guidance and animal viability in mice. (TRUE or FALSE).
13) Ig is an abbreviation for_____________________.
14) Drosophila DsCAM is part of the IgCAM superfamily. (TRUE or FALSE).
15) IgCAM receptors require Ca+2 for homophilic binding. (TRUE or FALSE).
16) Like the mammalian immune system, Drosophila DsCAM has many isoforms because of random somatic mutations. (TRUE or FALSE).
17) DsCAM is published to bind homophilically via its 2nd, 3rd and 7th Ig domains. (TRUE or FALSE).
18) Classical cadherin receptors require_______(an element) for homophilic binding.
19) Like DsCAMs, Protocadherins undergo DNA recombination to produce different combinations of variable (V) and constant (C) region exons into the final mRNA (TRUE or FALSE).
20) Like classical cadherins, the protocadherin alpha receptor was shown to bind homophilically (TRUE or FALSE).
21) How many times does the boss protein pass the membrane?_______.
22) sev is a tyrosine kinase receptor. (TRUE or FALSE).
23) sev is expressed in the R8 cell within an omatidium. (TRUE or FALSE).
24) The boss protein gives a signal to the R8 cell in order for it to differentiate. (TRUE or FALSE).
25) sev binds to the boss protein and internalizes it, thus causing the activation of the ras pathway. (TRUE or FALSE).