When DNA is compacted by histones into 10-nm and 30-nm fibers,the DNA is unable to interact with proteins required for geneexpression. Therefore, to allow for these proteins to act, thechromatin must constantly alter its structure. Which processescontribute to this activity?
| a. | nucleotide removal |
| b. | hydrolysis of DNA molecules where they are wrapped around thenucleosome core |
| c. | DNA coiling at or around H1 |
| d. | accessibility of heterochromatin to deacetylase enzymes |
| e. | acetylation of histone proteins |
What accounts for a small number of protein-coding genes ascompared to the larger number of proteins made by human cells?
| a. | alternative splicing |
| b. | enhancers |
| c. | miRNA |
| d. | protein degradation |
| e. | operons  |
Deletion mutations were created to determine the location andfunction of possible upstream regulatory sequences. The followingresults were obtained.
E.g., Deletion region -10 - -30 means thatthe region 10-30 nucleotides upstream of transcription start weredeleted and the transcription rate was reduced to 0%.
Which mutation represents the deletion of an enhancer?
Mutant | Deletion Region | % Transcription |
Wild Type | None | 100% |
A | -10 — -30 | 0% |
B | -30 — -100 | 50% |
C | -500 — -700 | 100% |
D | -700 — -900 | 45% |
E | -900 — -1100 | 30% |
F | -1100 — -1300 | 100% |
G | -1300 — -1500 | 150% |
Deletion mutations were created to determine the location andfunction of possible upstream regulatory sequences. The followingresults were obtained.
E.g., Deletion region -10 - -30 means thatthe region 10-30 nucleotides upstream of transcription start weredeleted and the transcription rate was reduced to 0%.
Which mutant represents the deletion of a silencer?
Mutant | Deletion Region | % Transcription |
Wild Type | None | 100% |
A | -10 — -30 | 0% |
B | -30 — -100 | 50% |
C | -500 — -700 | 100% |
D | -700 —  -900 | 45% |
E | -900 — -1100 | 30% |
F | -1100 — -1300 | 100% |
G | -1300 — -1500 | 150% |
