Molecular Biology Module 5: Gene Regulation

(USMLoid) 5 different variably sized fragments of DNA upstream (5') of Human Gene Y, between +1 and -1500, were fused to the 5' end of a fragment of DNA encoding the Luciferase enzyme. The start of transcription is at +1, the root of the bent arrow. A scale is shown at top left. These reporter constructs were then transfected into a human cell line. Cytosol extracts were prepared 24 hours later and luciferase activity measured. The results are shown to the right for each construct. Which of the following segments of the 5' upstream sequence is most likely to contain an enhancer element.

1

מיין לפי

(USMLoid) The Trp operon repressor involved in tryptophan biosynthesis in prokaryotes binds to which of the following sequences?

1

מיין לפי

(USMLoid) Which of the following binds to specific DNA sequences immediately upstream of the start of transcription.

1

מיין לפי

(USMLoid) A researcher has discovered a strain of E.coli bearing a mutant RPOD gene, resulting in the production of an altered RNA polymerase sigma factor. This mutation would most likely affect recognition of which of the following cis-acting regulatory sequences?

1

מיין לפי

You have generated an E. coli that contains two copies of the Lac operon. One copy is I-P+O+Z-Y+A+ . The other copy is I+P+O-Z+Y+A+. ( + indicates a wild type copy and - indicates a null-mutant, non-functional copy.) You grow these bacteria on petri plates containing only lactose as a carbon source and on petri plates containing both glucose and lactose as carbon sources. Both plates contain X-gal, which turns blue in the presence of active ß- galactosidase. Which of the following describes the growth of the bacteria on the two plates?

1

מיין לפי

You have generated an E. coli that contains two copies of the Lac operon. One copy is I-P+O+Z-Y+A+ . The other copy is I+P+O-Z+Y+A+. ( + indicates a wild type copy and - indicates a null-mutant, non-functional copy.) You grow these bacteria on petri plates containing only lactose as a carbon source and on petri plates containing both glucose and lactose as carbon sources. Both plates contain X-gal, which turns blue in the presence of active ß- galactosidase. Which of the following describes the growth of the bacteria on the two plates?

1

מיין לפי

Shown here are the promoter regions for two genes - Boris (Brs) and Natasha (Nts). Transcription begins at the arrow. Boxes A - G indicate the locations of identified protein-binding sequences. Which of the following is most likely true.

1

מיין לפי

This image shows the 5' end of the trp operon transcript. The numbered shaded areas are copies of homologous sequences with their orientations indicated by the arrowed ends. Under conditions of no tryptophan, which regions will base-pair with each other?

1

מיין לפי

Which of the following protein domains or motifs are found in eukaryotic transcription factor DNA binding or activation domains.

1

מיין לפי

This schema shows the activation of transcription of a eukaryotic gene (gene X). Indicate what component (A to D) in the drawing corresponds to each of the following.

1

מיין לפי

Molecular Biology Module 5: Gene Regulation

Discuss, Learn and be Happy דיון בשאלות

(USMLoid) The Trp operon repressor involved in tryptophan biosynthesis in prokaryotes binds to which of the following sequences?

(USMLoid) Which of the following binds to specific DNA sequences immediately upstream of the start of transcription.

(USMLoid) A researcher has discovered a strain of E.coli bearing a mutant RPOD gene, resulting in the production of an altered RNA polymerase sigma factor. This mutation would most likely affect recognition of which of the following cis-acting regulatory sequences?

Shown here are the promoter regions for two genes - Boris (Brs) and Natasha (Nts). Transcription begins at the arrow. Boxes A - G indicate the locations of identified protein-binding sequences. Which of the following is most likely true.

This image shows the 5' end of the trp operon transcript. The numbered shaded areas are copies of homologous sequences with their orientations indicated by the arrowed ends. Under conditions of no tryptophan, which regions will base-pair with each other?

Which of the following protein domains or motifs are found in eukaryotic transcription factor DNA binding or activation domains.

This schema shows the activation of transcription of a eukaryotic gene (gene X). Indicate what component (A to D) in the drawing corresponds to each of the following.