TLS Online TPP Program

#Question id: 7140


In thinking about the development of the wing imaginal disc of Drosophila, what is the significance of 'compartments'?

#Unit 5. Developmental Biology
  1. A compartment is a signaling center that controls antero-posterior patterning
  2. Compartments are developmental units, in that the wing forms from the 'wing compartment'
  3. Compartments are epithelial sacs, set aside during embryogenesis, that will give rise to adult structures such as wings after metamorphosis.
  4. Since cells in adjacent compartments have different lineage histories, adjacent compartments can adopt different fates and differentiation patterns, as in the formation of the anterior and posterior portions of the wing blade.
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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.

TLS Online TPP Program

#Question id: 4077

#Unit 3. Fundamental Processes

Which of the following is (are) associated with most polyadenylation events?

a. cleavage of the 5ยด end of the RNA molecule

b. an assembly of a large, multiprotein complex

c. the AAUAAA site upstream of where polyadenylation will occur

d. a GU-rich or U-rich region near the cleavage site

e. slow addition of A residues followed by rapid addition of 200 to 250 more A residues

TLS Online TPP Program

#Question id: 4078

#Unit 3. Fundamental Processes

Which of the following is (are) required for splicing to occur?

a. two transesterification reactions

b. intact, naturally occurring introns

c. formation of a lariat like structure

d. a branch-point G residue

TLS Online TPP Program

#Question id: 4079

#Unit 3. Fundamental Processes

What is the evidence that pre-mRNAs are not synthesized unless machinery for processing is properly positioned?