Question

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; each word or phrase should be used only once. 1 point each = 5 points.

In eucaryotic cells, general transcription factors are required for the activity of all promoters transcribed by RNA polymerase II. The assembly of the general transcription factors begins with the binding of the factor __________________ to DNA, causing a marked local distortion in the DNA. This factor binds at the DNA sequence called the __________________ box, which is typically located 25 nucleotides upstream from the transcription start site. Once RNA polymerase II has been brought to the promoter DNA, it must be released to begin making transcripts. This release process is facilitated by the addition of phosphate groups to the tail of RNA polymerase by the factor __________________. It must be remembered that the general transcription factors and RNA polymerase are not sufficient to initiate transcription in the cell and are affected by proteins bound thousands of nucleotides away from the promoter. Proteins that link the distantly bound transcription regulators to RNA polymerase and the general transcription factors include the large complex of proteins called the__________________. The packing of DNA into chromatin also affects transcriptional initiation, and histone __________________ is an enzyme that can render the DNA less accessible to the general transcription factors.
activator
CAP
deacetylase
enhancer
lac
ligase
mediator
TATA
TFIIA
TFIID
TFIIH

Answer 1

The transcription initiation in eukaryotic cells involves several general transcription factors and their assembly, regulation by proteins that act over large distances, and modifications to chromatin impacting DNA accessibility for transcription.

Step-by-step explanation:

In eukaryotic cells, general transcription factors are essential for RNA polymerase II to transcribe DNA into RNA. The process begins with the binding of the general transcription factor known as TFIID to the DNA, causing a distortion at the TATA box. When RNA polymerase II is ready to start transcription, it undergoes a change facilitated by the addition of phosphate groups by TFIIH. However, this complex isn't sufficient alone, as it requires the interaction with proteins bound at enhancers, which can be thousands of nucleotides away. These interactions are often mediated by a large complex of proteins known as the mediator. Furthermore, the transcriptional initiation process is impacted by the packaging of DNA into chromatin, with the enzyme deacetylase being able to modify histones and affect the accessibility of DNA to transcription factors.