#Question id: 11453
#Unit 7. System Physiology – Animal
Which type of receptor would you expect to be most abundant in the antennae of a moth?
#Question id: 7311
#Unit 5. Developmental Biology
According to the ABC model of flower development in Arabidopsis, three classes of organ identity genes— designated A, B, and C— are required to specify the identity of floral organs in each whorl of a flower. If wild type Arabidopsis were transformed with a chimeric gene composed of a C class promoter fused to a B class coding sequence, which of the following arrangements (outer to inner) would be predicted?
#Question id: 1521
#Unit 4. Cell Communication and Cell Signaling
we examine how the deregulation of growth-promoting and growth-inhibiting signaling pathways contributes to tumorigenesis. Mutations-
A. A mutation that alters a single amino acid (valine to glutamine) in the transmembrane region of the HER2 receptor
B. A deletion that causes loss of the extracellular ligand-binding domain in the EGF receptor Results-
i. dimerization of the receptor, even in the absence of the normal EGF-related ligand, transforming it into the oncoprotein, a constitutively active kinase
ii. to constitutive activation of the kinase activity of the resulting oncoprotein
iii. no dimerization, even in the presence of the normal EGF-related ligand, repression of kinase activity
which of the following results are displayed after these mutations?
#Question id: 5670
#Unit 5. Developmental Biology
Embryonic stem cells can be induced in the laboratory to differentiate into muscle, nerve, pancreatic, and other specialized cell types. It has recently become possible to trigger the dedifferentiation of somatic cells back into pluripotent cells (so-called induced pluripotent stem cells or iPS cells) by artificially enhancing the production of a relatively small number of key transcriptional factors known to be required for maintenance of pluripotency. Examples of such transcription factors are OCT4 and NANOG. The production of OCT4 and NANOG (and other key regulatory proteins) is stimulated by a transcription factor known as FOXP1, a member of the Forkhead family of DNA-binding proteins. There are two isoforms of FOXP1.
Which of the following statement regarding to FOXP1 is incorrect?
#Question id: 4104
#Unit 3. Fundamental Processes
Consider following statements for catalytic mechanism of RNA polymerase
A. RNA synthesis by RNA polymerase. The reaction involves two Mg2+ ions, coordinated to the phosphate groups of the incoming nucleoside triphosphates (NTPs)
B. Three Asp residues, which are highly conserved in the RNA polymerases of all species. One Mg2+ ion facilitates attack by the 39-hydroxyl group on the phosphate of the NTP; the other Mg2+ ion facilitates displacement of the pyrophosphate, and both metal ions stabilize the pentacovalent transition state.
C. About 17 bp of DNA are unwound at any given time. RNA polymerase and the transcription bubble move from left to right along the DNA as shown, facilitating RNA synthesis. Movement of an RNA polymerase along DNA tends to create negative supercoils (overwound DNA) ahead of the transcription bubble and positive supercoils (underwound DNA) behind it.
D. The RNA polymerase is in close contact with the DNA ahead of the transcription bubble as well as with the separated DNA strands and the RNA within and immediately behind the bubble. A channel in the protein funnels new NTPs to the polymerase active site. The polymerase footprint encompasses about 35 bp of DNA during elongation.