Which of the following structural motifs are notcommonly found in the DNA-binding motifs of proteins that act as transcriptional regulators?
A. homeodomain
B. leucine zipper
C. -barrel
D. helix-turn-helix
Which of the following eukaryotic recombination proteins is structurally and functionally similar to RecA?
A. Spo11
B. RuvAB
C. Rad50
D. Sgs1
E. Dmc1
Condensation of DNA yields the 30 nm filament. This filament:
A. is the most compact form of eukaryotic DNA.
B. is moderately condensed DNA, as facilitated by H1 and the N-terminal tails.
C. is also called the chromosomal scaffold.
D. includes tetranucleosomes, each 30 nm in diameter.
E. would not include histone variants.
Which of the following statements about probes used in hybridization methods are true?
A. The probe could be a gene from another species.
B. They are usually radiolabelled or conjugated with a fluorescent tag so they can be visualized.
C. They can be synthetic DNA sequences based on known amino acid sequences.
D. They can be based on DNA sequence information from a sequence database.
E. All of these statements about hybridization probes are true.
Which of the following is not a characteristic of a riboswitch?
A. They are structures that can form in the 5' untranslated region of some mRNA molecules.
B. They exert gene expression control only at the level of translation.
C. They may physically bind to small-molecule metabolites.
D. Ligand-binding to a riboswitch may sequester the Shine-Dalgarno sequence.
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