Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
95 Cards in this Set
- Front
- Back
|
Which of these contain the helix-turn-helix motif
|
The homeodomain motif
|
|
|
Which of the following is not a method of posttranscriptional control in eukaryotic cells?
|
Digesting the DNA immediately after translation
|
|
|
Enhancers are
|
Distant sites where regulatory proteins bind
|
|
|
Operons are
|
In prokaryotic cells
|
|
|
Which of these is not a stage in a genetic experiment?
|
DNA fingerprinting
|
|
|
In screening clones, it is common to use
|
Antibiotics
|
|
|
In order for a gene to be transcribed, RNA polymerase must have access to the DNA helix and be able to bind the gene’s
|
Promoter
|
|
|
Catabolite repression in E. coli bacteria, involving the catabolite activator protein (CAP), is actually a type of positive regulation, because
|
cAMP-CAP helps RNA polymerase to initiate transcription
|
|
|
Jacob and Monod were intellectually primed to draw the conclusions they did concerning regulation of the lac operon. In part, this was due to their fascination with mechanisms of enzyme regulation. They knew that the activity of some enzymes was regulated when the reaction product bound to the enzyme, changing its shape and therefore activity. This knowledge allowed them to easily make the intellectual leap to propose:
|
allosteric control of the repressor
|
|
|
Extracellular glucose inhibits transcription of the lac operon by:
|
reducing the levels of intracellular cAMP
|
|
|
According the steric hindrance model for repressor function, if a DNA footprinting study were performed to examine the DNA sequence that constitutes the promoter, it would be found that:
|
This sequence would be protected from DNase digestion.
|
|
|
How does the inducer work to change the repressor’s affinity for DNA?
|
Inducer binding changes the repressor’s shape to alter the positioning of the DNA binding domains so they no longer interact with DNA.
|
|
|
Adenylyl cyclase is the enzyme that:
|
produces cAMP from ATP
|
|
|
Because the goal was to regulate expression of tyrosinase, what portion of the lac operon do you think was added to this mouse gene?
|
the lac operator
|
|
|
In addition to lac operon/mouse tyrosinase DNA, what other gene must be added to mice to regulate tyrosinase expression?
|
the lacI gene
|
|
|
If the genetically engineered albino mice were given no special treatment, how would the tyrosinase gene be expressed?
|
It would not be transcribed.
|
|
|
In what kind of population is random genetic drift most pronounced?
|
Drift is greatest in small populations
|
|
|
How did Cronin et al. activate expression of tyrosinase to change the color of a white (albino) mouse to brown?
|
They added IPTG, a lactose analog, to the drinking water.
|
|
|
Controlling the production of a pigment is interesting, but in itself seems more a stunt than a valuable research endeavor. What is the broader significance of the results of Cronin et al.?
|
This same genetic system potentially can be used to control the expression of almost any gene.
|
|
|
Both replica plates are sprayed with ONPG. The vast majority of colonies are white on the glucosecontaining plates and yellow on the lactose-containing plates, but you discover a single colony that is yellow on both types of plates. At this point, you suspect this rare colony contains:
|
a mutation in the lacI gene
|
|
|
Full induction of the lac operon occurs when:
|
lactose levels are high and glucose levels are low
|
|
|
Nevertheless, the percentage of different flower colors remains stable in the study population from year to year. Which of these statements might explain this observation?
|
Flower color is not heritable but is instead environmentally determined.
|
|
|
Imagine there are 100 people, and that 96 of those people have detached earlobes (a dominant trait). If this population is in Hardy Weinberg equilibrium, how many people are heterozygous for that trait?
|
32
|
|
|
bacterial colonies remain their normal white color. What is X-Gal likely to be?"
|
a compound chemically similar to lactose
|
|
|
Regulatory transcription factors:
|
influence the assembly of the basal transcription complex
|
|
|
How does a gene library differ from a gene clone?
|
A gene library contains many different sequences; a gene clone contains one type of sequence.
|
|
|
you find no human growth hormone is expressed. Why do you think this procedure failed?
|
Bacteria cannot carry out splicing.
|
|
|
What is alternative splicing?
|
mRNA processing events that lead to different combinations of exons being spliced together
|
|
|
What concentrations of the substances below will allow the lac operon to be frequently transcribed?
|
Cyclic AMP must be high, lactose must be high
|
|
|
Which of the following types of selection is most likely to be found in a lake with a high density of these fish?
|
Disruptive selection
|
|
|
Which of the following does NOT tend to promote speciation?
|
Gene flow
|
|
|
In eukaryotes, why are certain genes expressed only in certain types of cells?
|
Regulatory transcription factors vary from cell to cell.
|
|
|
A major function of the tumor suppressor protein p53 is to
|
Inhibit the transcription of genes that promote cell division.
|
|
|
A probe
|
Is used to find a DNA sequence of interest.
|
|
|
You make two replicate plates, one on glucose, one on lactose, which are treated with ONPG. One colony is yellow on both plates; that colony is a mutant for
|
lac I
|
|
|
One such source was studies of retrovirus replication. What aspect of a common cloning procedure makes direct use of this knowledge?
|
synthesizing cDNAs
|
|
|
If ONPG is cleaved (turns yellow) despite the absence of lactose, the cells must be:
|
lac I mutants
|
|
|
In the lac operon, what is the inducer?
|
Lactose
|
|
|
What DNA sequence information is critical to the success of PCR?
|
The sequence of the ends of the DNA to be amplified must be known.
|
|
|
The human genome project revealed that there are many more proteins than genes, indicating that one gene can code for several proteins. How is this possible?
|
mRNA can have alternative splicing
|
|
|
Lactose binding to the repressor protein is an example of
|
Negative control
|
|
|
What is the primary difference between PCR and more traditional cloning procedures?
|
PCR eliminates the need for restriction enzymes, vectors and cells.
|
|
|
The mechanism for the spread of LINES involves some unusual elements. One of these unusual features is:
|
the transport of mRNA from the cytoplasm to the nucleus
|
|
|
STAT’s are a form of
|
Regulatory transcription factors
|
|
|
If DNA were inflexible, which of the following forms of regulation would be most strongly affected?
|
the ability of enhancers to influence transcription
|
|
|
Which components of the lac operon might you expect to see utilized in the regulation of other genes?
|
The CAP binding site
|
|
|
Which of the following counteracts reproductive isolation?
|
Gene flow
|
|
|
Imagine you’ve isolated a yeast mutant that contains histones resistant to acetylation. What is the phenotype for this mutant?
|
The mutant shows generally low levels of gene expression.
|
|
|
If the researcher removes all slugs from the study population, what would you expect to happen to the distribution of flower colors in the population over time?
|
The percentage of pink flowers should increase over time.
|
|
|
How does a regulatory protein that binds to a specific DNA sequence recognize this sequence?
|
The regulatory protein detects the portion of the base pairs that projects into the grooves of the double stranded DNA.
|
|
|
The Sigma factor in prokaryotes is analogous to the _____ in eukaryotes.
|
The TATA binding protein
|
|
|
Prokaryotes and Eukaryotes share one method of gene regulation. Which of the following is common to both types of cells?
|
Transcriptional control
|
|
|
Which of the following biological processes leads to adaptation?
|
natural selection
|
|
|
What are the four requirements for evolution by natural selection in a given population?
|
(1) Individuals in a population vary; (2) the variation is heritable; (3) some individuals produce more offspring than others; (4) certain traits lead to greater reproductive success than other traits.
|
|
|
Which of these changes to the histone structure generates dissociation from DNA?
|
acetylation (negative charge)
|
|
|
A major function of the tumor suppressor protein p53 is to:
|
activate the transcription of genes that inhibit cell division
|
|
|
Genetic drift is an evolutionary process involving:
|
Random factors
|
|
|
Not long ago, it was believed that a count of the number of genes in an organism would provide a count of the number of gene products. This is now known to be incorrect, largely due to the discovery of widespread:
|
alternative splicing
|
|
|
Which of the following sequences is in the correct order for one cycle of PCR?
|
Denature DNA; anneal primers; extend primers.
|
|
|
Which of the following best describes pseudogenes?
|
Sequences of DNA that are similar to a functional gene, but do not produce a product
|
|
|
To begin the hunt for the human growth hormone gene, researchers created a cDNA library from cells in the pituitary gland. What did this library contain?
|
DNA versions of all the mRNAs in the pituitary-gland cells
|
|
|
What is the key property of DNase that makes it useful for assessing whether chromatin is in a closed (tightly condensed) or open (loosely packed) configuration?
|
DNase preferentially digests DNA not associated with protein.
|
|
|
In evolutionary terms, the most fit individual is the one who is:
|
The most reproductively productive
|
|
|
What does the lateral transfer of genes refer to?
|
the movement of genes from one species to another
|
|
|
Imagine you have isolated two different mutant colonies of E. coli that remain white when sprayed with ONPG. You name them mutant A and mutant B. Separate cultures of these mutants are grown, and the cells are harvested (collected) and lysed (broken open). ONPG is added to lysed cells (lysates) of each culture. The lysate of mutant A develops yellow color; the lysate of mutant B does not. What can you make of this?
|
A. Mutant A has a mutation in the lacY gene; mutant B has a mutation in the lacZ gene.
|
|
|
Compared to prokaryotes, eukaryotes have more complex regulation of transcription and translation. Which of these ways is considered post-transcriptional control?
|
Alternative splicing
|
|
|
What is the leading hypothesis to explain the paradox that large, complex eukaryotes such as humans have relatively small numbers of genes?
|
alternative splicing of mRNAs
|
|
|
A mutation in the lacI gene that resulted in a major conformational change in the repressor protein so that it was unable to bind to the operator would result in
|
continual production of ß-galactosidase.
|
|
|
The lac promoter is weak; for it to be fully induced:
|
cyclic AMP and lactose must be present
|
|
|
What is one reason that glucose and lactose are not metabolized at the same time in E. coli, even when both are present?
|
Glucose reduces transcription of lacZ and lacY.
|
|
|
Restriction Fragment Length Polymorphisms (RFLP’s):
|
individual variation in the size of DNA pieces cut with restriction enzymes. These variations are used to identify particular individuals or species
|
|
|
What does lac I do?
|
It makes the repressor protein
|
|
|
Which of the following is an example of a compound that is NOT involved in negative control of its own production
|
lactose
|
|
|
What are four mechanisms that cause allele frequencies to change?
|
mutation, selection, migration, and genetic drift
|
|
|
When glucose is present in a bacterial cell, either because it is in the medium, or as a product of lactose catabolism, ß-galactosidase production is reduced. This is an example of
|
negative control
|
|
|
Which of the following is involved in transcription of prokaryotes, but NOT in eukaryotic transcription?
|
operators
|
|
|
Proteins are often modified before they are functional. If these modifications do not occur, this would be a form of:
|
Post translational control
|
|
|
Extracellular glucose inhibits transcription of the lac operon by:
|
reducing the levels of intracellular cAMP
|
|
|
Which of the following shown proteins have analogous functions in eukaryotes and in E. coli?
|
TATA binding protein and sigma protein
|
|
|
What feature of the repressor protein accounts for the dyad symmetry of each operator of the lac operon?
|
The DNA binding domains of the repressor function as dimers.
|
|
|
Sticky ends:
|
The result of a restriction enzyme cutting DNA so that there is a 5’ overhanging end in the plasmid. This overhang facilitates insertion of novel DNA pieces.
|
|
|
If you forgot to treat filters (in cloning) with a chemical to make DNAs single stranded, then…
|
The X-ray film would not show any black spots.
|
|
|
What would happen if we did not use polymerase that was heat resistant during PCR?
|
There would be few copies of product DNA
|
|
|
Which of the treatments above would results in the production of Beta-galactosidase?
|
glucose+lactose
|
|
|
You would expect the expect the enzyme to cut:
|
in the open DNA
|
|
|
Which of these regulatory elements Is physically closested to a gene that is to be transcribed?
|
TATA box/promoter
|
|
|
Which of these is tissue specific?
|
regulatory proteins
|
|
|
Which of these events happen first?
|
HAT proteins provide an acetyl group to histones
|
|
|
Which of the following properties do you predict to be most critical to histone association with DNA?
|
Histones are positively charged
|
|
|
The phenotype associated with a mutan form of p53 that binds DNA much more tightly than wildtype p53 is predicted to be?
|
an arrent of cell division and triggering of cell death
|
|
|
The eukaryotic protein that functions most like the bacterial sigma factor is
|
TATA binding protein
|
|
|
Which one of these attributes of cells allows for the insection of a gene into a plasmid?
|
Endonucleases
|
|
|
How can an amino acid sequence be used to design a gene-specific hybridization probe?
|
use the codon table to deduce a set of nucleotide sequences
|
|
|
What is the use of a cDNA library
|
particular cloned genes (cDNA) can be isolated from a cDNA library
|
|
|
genetic engineering technies have developed…
|
using retroviruses as vectors to carry genes into bacterial cells
|
