Question

1. trans-acting factors are able to regulate target genes from any chromosome, whereas cis-acting elements can only regulate genes located in the same chromosome.

	a.	True only in operons. In Eukaryotic systems, trans-acting factors only regulate genes in the same chromosome.
	b.	True only in Eukaryotes. Prokaryotes don’t have cis-acting elements.
	c.	True for any organism.
	d.	False. The statement is erroneous

2. Unlike activators, repressors never affect chromatin structure. Repressors inhibit transcription only by binding to the binding sites of activators.

a.True

b. False

3. Which of the following best describes the mechanism by which steroid hormones control gene expression?

	a.	Steroid hormones enter a cell, bind directly to hormone response elements (HREs), and enhance transcription.
	b.	Chaperone proteins transport steroid hormones into the cell and guide them to their target genes.
	c.	Steroid hormones transport mRNA from the nucleus into the cytoplasm, where it is translated into protein.
	d.	Steroid hormones that enter the cell activate receptors. These hormone-receptor complexes then bind HREs and influence gene expression.

4. Insulators are ____

	a.	sequences that regulate the interactions of specific enhancers and their intended target promoters.
	b.	proteins that prevent the formation of DNA loops.
	c.	regions of DNA spanning the distance between enhancer and core promoter, sometimes 1 million bases long.
	d.	variations of silencer sequences only present in yeast.

Answer 1

Based on the given data,

1) The Trans-acting factors are intermolecular and the cis-acting elements are intramolecular. Both these factors present in Eukaryotes and prokaryotes. Hence, the correct option is (c) True for any organism.

2) True

3) Steroid hormones that enter the cell activate receptors. These hormone-receptor complexes then bind HREs and influence gene expression. Thus, the correct option is (d).

4) Sequences that regulate the interactions of specific enhancers and their intended target promoters. Thus, the correct option is (a).