Ch. 2 Study Questions Flashcards
Name three processing steps undergone by mRNA
- Polyadenylation
- Capping
- Splicing
What is the function of polyadenylate polymerase?
Digests RNA and adds adenines to the 3’ end of the transcript
What is unusual about the phosphodiester bond formed between mRNA and its 5’ cap?
The 5’ cap is attached by an unusual 5’-to-5’ pyrophosphate linkage
The parts of the hnRNA that are translated into protein (open reading frames) are the _______.
exons
The intervening sequences that interrupt protein coding sequences in hnRNA are _______.
introns
Proteins that bind to DNA to control gene expression are called _______ factors
transcription
How might a single mRNA produce more than one protein product?
A single RNA may be alternatively spliced to produce more than one product
The type of transcription producing RNA that is continually required and relatively abundant in the cell is called _______ transcription.
constitutive
A set of structural genes transcribed together on one polycistronic mRNA is called an _______.
operon
Indicate whether the following events would increase or decrease expression of a gene:
a. Methylation of cytosine bases 5’ to the gene
b. Histone acetylation close to the gene
c. siRNAs complementary to the gene transcript
a. Decrease
b. Increase
c. Decrease
How does the complementaritry of siRNA to its mRNA differ from that of miRNA?
The complementarity of siRNA is exact, and that of miRNA is imperfect
What is imprinting in DNA?
Marking of selective areas of DNA usually by methylation
What sequence of structures in DNA, usually found 5’ to structural genes, are frequent sites of DNA methylation?
CpG islands 5’ to the structural genes
What is RISC?
RNA-indiced silencing complex
Mediates the specific interaction between siRNA or miRNA and the target RNA
The binding sites on DNA for proteins that control gene expression are _______.
cis factors
