TLS Online TPP Program

#Question id: 7102


How is the Spemann organizer distinguished from the other mesodermal cells during induction by the cells of the vegetal region?

#Unit 5. Developmental Biology
  1. The cells of the Spemann organizer become different as they pass over the dorsal lip of the blastopore during gastrulation.
  2. Beta-catenin, which has become localized to the nucleus in the Nieuwkoop center as a result of cortical rotation, turns on high levels of the TGF- signalling molecule, Nodal, and this relatively high level distinguishes the adjacent cells of the Spemann organizer from the rest of the mesoderm.
  3. The Spemann organizer is formed from cells of the Nieuwkoop center, which have migrated upward in the embryo.
  4. BMP-4 signalling from ventral mesodermal cells toward the dorsal region specify the dorsal-most cells as organizer.
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TLS Online TPP Program

#Question id: 4071

#Unit 3. Fundamental Processes

The fact that a specific protein leaves a “footprint” on a DNA molecule is indicative of

a. a lack of interaction between the specific protein and DNA.

b. protection from DNAse by the specific protein.

c. binding of the specific protein to all types of DNA.

d. binding of the specific protein to a specific sequence of DNA.

TLS Online TPP Program

#Question id: 4072

#Unit 3. Fundamental Processes

The C-terminal activation domain of transcriptional activators is capable of

a. binding to DNA. 

b. stimulating transcription.

c. interaction with other transcriptional machinery.

d. functioning in a fusion with a DNA-binding domain from an unrelated transcriptional activator.

TLS Online TPP Program

#Question id: 4073

#Unit 3. Fundamental Processes

The expression of which gene(s) is (are) regulated by promoter proximal pausing?

TLS Online TPP Program

#Question id: 4074

#Unit 3. Fundamental Processes

The promoter sequences of RNA polymerase III-transcribed genes are located

TLS Online TPP Program

#Question id: 4075

#Unit 3. Fundamental Processes

Pre-mRNA molecules

a. exist as free RNA molecules in eukaryotic cells.

b. are associated with an abundant set of nuclear proteins.

c. are mostly located in the cytoplasm.

d. are located in the nucleus.

TLS Online TPP Program

#Question id: 4076

#Unit 3. Fundamental Processes

RNA-binding proteins

a. can be identified by chromatography of UV irradiated nuclear extracts over oligo-dT columns.

b. can be identified by sequence homology to known RNA-binding domains.

c. have a conserved structure as seen by X-ray crystallographic analysis.

d. alter the secondary structure of pre-mRNAs, which decreases interactions with other RNAs or proteins.

e. always remain in the nucleus.