Chapter 15
Which of the following is a means of controlling eukaryotic gene expression?
-DNA packing -transcriptional regulation -mRNA processing -methylation of DNA
Which statement about feedback inhibition is true?
-It is typically found in anabolic pathways -It allows a cell to adapt quickly to fluctuation in the availability of important substances -The end produce of the metabolic pathway controls the activity of the first enzyme in the pathway -If the end product accumulates in the cell the whole pathway is shut down
Post-transcriptional controls...
-can include translational controls -can affect mRNA stability -may regulate the rate at which a molecule is translated -can regulate mRNA splicing
Enhancers...
-increase the rate of transcription -are found in eukaryotic genomes -may be located upstream or downstream from the genes they regulate -may be located thousands of base pairs away from the promoter
A scientist wishing to create an organism capable of breaking down several kinds of toxic waste combines genes from several species of bacteria to create a singles "superbacterium." Which of the following would be needed to do this?
-nucleic acid probes -DNA ligase -plasmids -restriction enzymes
A high rate of gene transcription in eukaryotic cells is usually dependent on...
-specific binding of activator molecules to enhancers -protein-protein interaction that are promoted by the activation domains of activator proteins
Why do both bacteria and humans need tryptophan?
It is one of the 20 amino acids used by all organisms to synthesize protein
You have inserted the gene for human growth factor into the E.coli lactose operon, replacing the structural genes with the gene for human growth factor. What substrate must you add to your culture of bacteria to cause them to produce human growth factor for you?
allolactose
Although the number of genes in the human genome is surprisingly low compared to less complex organisms, the number of possible products from those genes is greatly amplified by...
alternate arrangements of exons from a primary transcript
In prokaryotic genomes, groups of functionally related genes along with their promoter and operators are found together in...
an operon
DNA synthesized using a RNA template is called...
cDNA
DNA synthesized using an RNA template is called...
cDNA
A scientist clones a regulatory gene that is involved in controlling the expression of other genes, and discovers that the regulatory gene encodes a histone deacetylase enzyme. It is likely that this enzyme regulates gene expression by...
causing tighter packing of the chromatin at the target gene, thereby inhibiting transcription
A bacterium can make the amino acid glycine or absorb it from it surroundings. A biochemist finds that glycine binds to a repressor protein and causes the repressor to bind to the bacterial chromosome, turning off an operon. If it is like other similar operons, the presence of glycine will result in the...
cessation of the synthesis of glycine
In eukaryotes, DNA packing seems to affect gene expression primarily by...
controlling access to DNA
Gene expression in bacteria is regulated primarily by...
controlling the transcription of genes into mRNA
MicroRNAs and small interfering RNAs both function similarly in "silencing" genes. What are two ways in which they may act?
degrade mRNA and bind to complementary mRNA sequence to prevent translation
In a eukaryote, activating transcription factors may simulate gene expression by binding to a DNA site called a...
enhancer
Which of the following best describes the makeup of the human genome?
genes for noncoding RNA make up the majority of meaningful genetic information in the human genome
The expression of a gene located in a tightly coiled region of DNA can be promoted by...
histone acetylation
A nucleic acid probe is used to...
identify genes that have been inserted into bacterial plasmids or separated by electrophoresis
The control of gene expression is more complex in multicellular eukaryotes than in prokaryotes because...
in a multicellular eukaryote, different cells are specialized for different functions
What is the evolutionary significance of alternative RNA splicing?
it expands the number of proteins that can be coded for by one gene, increasing an organism's ability to produce novel proteins
What determines how long a particular mRNA molecule will persist in a eukaryotic cell?
nucleotide sequences in the poly-A tail
In general, operons that encode the enzymes of a biosynthetic (anabolic) pathway are___, and those encoding the enzymes of a catabolic pathway are___.
repressible and inducible
What is the source of the reverse trancriptase used in recombinant DNA technology?
retrovirus
Which arrangement of the following four enzymes represents the order in which they would be used in a typical gene-cloning experiment resulting in the insertion of a cDNA into a bacterial plasmid? Begin with the gene's mRNA transcript.
reverse transcriptase, DNA polymerase, restriction enzyme, DNA ligase
Which arrangement of the following four enzymes represents the order in which they would be used in a typical gene-cloning experiment resulting in the insertion of a cDNA into bacterial plasmid? Begin with the gene's mRNA transcript.
reverse transcriptase, DNA polymerase, restriction enzyme, DNA ligase
In some cases DNA methylation and histone deacetylation combine to...
silence certain genes
In an inducible operon, the inducer is often the___in the pathway being regulated; the inducer binds to the___, thus rendering it___.
substrae...repressor...inactive
Both repressible and inducible operons control gene expression at the level of...
transcription
Because eukaryotic genes contain introns, they cannot be translated by bacteria, which lack RNA-splicing machinery. But if you want to engineer a bacterium to produce a eukaryotic protein, you can synthesize a gene without introns. A good way to do this is to...
work backward form mRNA to make a version of the gene without introns
