Chapter 19, Problem 7TYU

Write the word TRUE if the statement is correct and if false, replace the underlined words with the correct one. 1. Heterochromatin is typically gene-rich and composed of loosely-packed DNA that is transcriptionally active. 2. Molecular switches regulate the expression of genes by directing where and when genes should be turned on or off depending on the cell signal. 3. DNA Methylation and acetylation of histones are inverselycorrelated 4. Specialized cells produce specialized proteins derived from luxury genes which are constitutively expressed. 5. In mammals, methylation patterns that regulate DNA structure and gene expression become evident from the gastrula stage.

The following image shows the 'beads-on-a-string' model of DNA and the effects of histone modification on chromatin structure. What effect does histone acetylation have on Gene 1? Gene 1 De-acetylation Acetylation Ac Ac Gene 1 Ac Ac Ac O Acetylation increases expression of Gene 1 O Acetylation decreases expression of Gene 1 O Acetylation causes a mutation in Gene 1 O There is no way to tell from this figure

You discover a histone variant that has more positive charge than conventional histone proteins. What effect do you predict this histone variant would have when it is inserted into chromatin? A decrease in the strength of histone-DNA interaction, making chromatin less condensed and increasing gene expression An increase in the strength of histone-DNA interaction, making chromatin less condensed and decreasing gene expression An increase in the strength of histone-DNA interaction, making chromatin more condensed and decreasing gene expression O A decrease in the strength of histone-DNA interaction, making chromatin less condensed and decreasing gene expression