Recent discoveries on causes of fragile- X syndrome, myotonic dystrophy, and Huntington disease indicate what type of genetic alteration?
expanding trinucleotide repeats
The ______ consists of modifications to histone proteins that affect the expression of DNA sequences.
transcriptionalrepression by methylation of DNA is most common in sequences called _____ islands.
The ____ is a type of _____ protein that binds to a region of DNA in the promoter of a gene called the _____ and prevents _____ from taking place.
repressor, regulatory, operator, transcription
Mutations in the lacI and lacO genes in the lactose system often lead to full production of the three structural genes related to the lac operon even with no lactose available to the organism. Such mutations would be called________.
The _________ can be used to quickly screen chemicals for their ability to be mutagenic (and hence potentially carcinogenic).
Mutations in the promoter region of the b-globin gene indicate that some areas are more sensitive than others. When mutations occur in consensus sequences (modular elements such as GC box, CAAT box, TATA box) transcription ________________.
_______________ is also known as RNA silencing and posttranscriptional gene silencing.
A _________________, which binds to a core promoter, consists of general transcription factors and RNA polymerase.
basal transcription apparatus
The process of error correction of mismatched bases carried out by DNA polymerases is called
Parts of chromosomes that are not methylated for inactivation, but rather are less dense-staining and are likely active in transcription in the cell.
One type of mutation involves the replacement of a purine with a purine. What general term is associated with this mutational phenomena?
The region of a protein that is capable of holding on to a particular nucleotide sequence in order to affect proper gene regulation.
DNA binding domain
The process by which excessive numbers of a sex chromosome are corrected, often by methylating the X chromosome to form a Barr body.
This term describes genetic elements that affect other elements only when they are located adjacent to them. For example, the operator has this effect on its structural genes.
________act as intermediaries between _______ and specific _____ sequences to modify chromatin structure and activate transcription.
transcriptional activators, chromatin remodeling complexes, DNA
_____________ are complexes where, among other activities, a great deal of RNA degradation takes place.
This process moves a nucleosome from the TATA box of a gene's promoter so that transcription can occur.
This structure forms when an extra X chromosome is methylated and largely inactivated. It is most commonly found in females.
These are factors that need not be adjacent to the genes they control. An example would be the lac operon's repressor protein.
Degradation of a eukaryotic mRNA is generally preceded by shortening of the _____________.
poly A tail
When siRNAs are present, the rate of mRNA degradation_____________ and the rate of protein production ___________.
Proteins that affect chromatin structure without altering histone chemical structure are called _______________.
chromatin remodeling complex
A highly-methylated region of a chromosome that has become largely deactivated and can be seen as dense-regions when viewed using electron microscopy.
Since the binding of the _________ to the _________ prevents it from binding to _________ by causing a conformational change in its structure, it is called an _________ protein.
inducer, repressor, DNA sequence, allosteric
Apurinic (and apyrimidinic) sites (AP sites) involve a spontaneous loss of ______________ in an intact double-helix DNA molecule
Indicate the level of activity of the lac operon under the medium conditions listed below:
a) No lactose present, no glucose present
b) Lactose present, no glucose present
c) No lactose present, glucose present
d) Lactose present, glucose present
Enter "high" or "off" , separated by a comma, in the order of the a, b, c, d scenarios into the answer box.
off, high, off, off
When regions around genes become sensitive to the enzyme ______________ this is an indication that those regions are becoming ______________ active.
DNAse I, transcriptionally
The ____________________ stabilizes the 5' cap, which must be removed before the mRNA molecule can be degraded from the 5' end.
poly A tail
A eukaryotic DNA sequence that affects transcription at distant promoters is called a(n) ________________.
(long answer) Name six different levels at which gene expression might be controlled.
gene structure, transcription, mRNA processing, RNA stability, translation, posttranslational modification
(long answer) List five levels at which gene control can take place in eukaryotes.
chromatin structure, RNA processing, RNA stability, RNA silencing, posttranslational modification