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;
232 Cards in this Set
- Front
- Back
|
Motif
|
a common shape or domain of a protein.
|
|
|
p53
|
a gene that codes for a regulatory transcription factor; when this gene is mutated, the protein cannot bind to the enhancer for the tumor suppressor genes. The cell cycle goes on continuously.
|
|
|
Constitutively
|
a gene that is expressed all the time.
|
|
|
Operon
|
a group of genes with related functions in bacteria.
|
|
|
Inducer
|
a molecule that turns on a gene (i.e. lactose turns on the lac operon).
|
|
|
Repressor
|
a protein that binds to DNA so that the RNA polymerase is blocked.
|
|
|
Dyad or two fold symmetry
|
a sequence of DNA that is repeated symmetrically, so that binding proteins recognize a binding site.
|
|
|
Alternative splicing
|
different ways of completing a mRNA to make a variety of proteins.
|
|
|
Chromatin
|
DNA + histones. The chromatin must be remolded so that DNA is available before transcription.
|
|
|
Histones
|
DNA associated proteins.
|
|
|
Enhancers
|
DNA that binds proteins that encourage transcription of a gene by folding the DNA. These are usually located far away from a gene.
|
|
|
Nucleosomes
|
DNA wound around histones = a part of the chromatin.
|
|
|
Tumor suppressor genes
|
genes that stop the cell cycle.
|
|
|
Post-translational control
|
proteins are manufactured, but they may not be activated or completed until they are needed (i.e. no folding or phosphate groups).
|
|
|
Signal transducers and activators of transcription (STAT’s)
|
proteins that are in the cytoplasm and travel to the nucleus to bind to the enhancers to begin transcription. These are specialized for each type of cell.
|
|
|
Regulatory transcription factors
|
proteins that bind to the enhancers that cause the DNA to fold so that transcription is encouraged.
|
|
|
Basal transcription factors
|
proteins that bind to the promoter (in prokaryotes this would be the same as the sigma) so that the RNA polymerase will begin transcription.
|
|
|
Histone acetyl transferases (HAT’s)
|
proteins that change the charge of histones that allow DNA to be repelled, unwinding the chromatin.
|
|
|
Domains
|
regions of a large protein.
|
|
|
Positive control
|
something must be added for transcription to occur.
|
|
|
Negative control
|
something must be taken away for transcription to occur.
|
|
|
Operator
|
the binding site for the repressor.
|
|
|
Catabolite repression
|
the product of reaction inhibits transcription of the enzyme for that reaction.
|
|
|
Basal transcription complex
|
the promoter, the basal transcription factors and the RNA polymerase.
|
|
|
Transcriptional control
|
up or down regulation of mRNA production.
|
|
|
Translational control
|
up or down regulation of protein production.
|
|
|
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
|
|
|
Which of the following is NOT associated with inbreeding?
|
Allele frequencies change in a population.
|
|
|
Homology:
|
a basic ground plan of structures, genes or developmental sequence that is altered slightly between species that are related by common ancestry.
|
|
|
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
|
|
|
What is a plasmid?
|
a circular DNA molecule, found in many bacteria and certain eukaryotes, that replicates independently of the main chromosome(s)
|
|
|
An enhancer is
|
a coding region of DNA that may be located within an intron, Enhancers can be located 5’ or 3’ to the gene, or in introns.
|
|
|
Compared to prokaryotes, eukaryotes have more complex regulation of transcription and translation. Which of these ways is considered post-transcriptional control?
|
Alternative splicing
|
|
|
cDNA library:
|
a collection of bacteria that each contain a vector with one cDNA strand. The total amount of cDNA is found in the bacteria collectively.
|
|
|
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 compound known as X-Gal is widely used in molecular genetic research. When
wild-type (normal) E. coli is grown on medium containing X-Gal, the bacterial colonies turn blue. In contrast, when lacZ mutants are grown on medium containing X-Gal, the bacterial colonies remain their normal white color. What is X-Gal likely to be?" |
a compound chemically similar to lactose
|
|
|
What is a tumor suppressor?
|
a gene associated with tumor formation when its product does not function
|
|
|
The phenotype associated with a mutant form of p53 that binds DNA much more tightly than wild-type (normal) p53 is predicted to be:
|
an arrest of cell division and triggering of cell death
|
|
|
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.
|
|
|
What is a pseudogene?
|
a gene whose sequence is similar to functioning genes, but is not transcribed
|
|
|
Restriction endonuclease:
|
An enzyme that cuts unmethylated (viral/plasmid) DNA at a particular sequence of base pairs.
|
|
|
Reverse transcriptase:
|
an enzyme that makes DNA from an RNA template.
|
|
|
Evolution:
|
a genetically based change in characteristics of a population over time.
|
|
|
Gene pool:
|
a group of interbreeding individuals.
|
|
|
Which of the following results from convergent evolution?
|
Analogous traits result from convergent evolution
|
|
|
Taq polymerase:
|
a heat stable form of DNA polymerase that is used in PCR.
|
|
|
Some beetles and flies (insects) have antler-like structures on their heads, much like male deer (chordates) do. The existence of antlers in beetle, fly, and deer species with strong male-male competition is an example of:
|
analogy/convergent evolution
|
|
|
Adaptation:
|
a heritable trait that increases an individual’s fitness.
|
|
|
Which of the following is NOT a major source of genetic variation in bacteria?
|
binary fission
|
|
|
Inbreeding depression:
|
a loss of fitness that occurs because of an individual that is homozygous for a deleterious trait that originated from one individual.
|
|
|
What is catabolite repression?
|
a mechanism that turns off the enzymes responsible for catabolic reactions when the product is present
|
|
|
Vicariance refers to
|
a pattern of speciation in which a population is subdivided by a geographic barrier.
|
|
|
Gene expression in bacteria can be modified in bacterial cells
|
both quantitatively and qualitatively
|
|
|
Probe:
|
a piece of single stranded DNA that is designed to target a gene that it is complimentary to. The probe is labeled in some way, such as radioactivity or fluorescent markings.
|
|
|
Vector:
|
a plasmid that carries recombinant DNA into a new host, usually a bacterium. The vector is usually carried by a virus.
|
|
|
How is the pedigree of an individual generally constructed?
|
by interviewing the individual regarding the sex and physical traits of his or her family members
|
|
|
Population
|
a group of individuals that live in the same area and that regularly interbreed.
|
|
|
In the form of gene therapy used successfully for severe combined immunodeficiency syndrome (SCID)-X1, the genetic engineering of human cells is done:
|
by isolating the patient’s bone marrow cells, treating them with genetically engineered viruses, and injecting these cells back into the patient’s bone marrow
|
|
|
Which of the following is the best modern definition of evolution?
|
change in allele frequencies in a population over time
|
|
|
What is alternative splicing?
|
changes in mRNA processing that lead to different combinations of exons being spliced together
|
|
|
What does descent with modification refer to?
|
changes in populations through time
|
|
|
What is a helix-turn-helix motif?
|
a protein domain involved in DNA binding
|
|
|
One way to detect alternative splicing of a given gene is to:
|
compare the sequence of mature mRNAs made from this gene
|
|
|
Which of the following could be a mechanism to prevent cancer?
|
a protein similar in structure and function to p53
|
|
|
cDNA:
|
complimentary DNA; DNA that is made via reverse transcriptase from RNA.
|
|
|
If a bacteria were to develop resistance to an antibiotic, which of the following methods would most likely result in the development of antibiotic resistance in other species of bacteria that are located in close proximity to the resistant bacteria?
|
conjugation
|
|
|
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.
|
|
|
How can Darwinian fitness be estimated?
|
Count the number of offspring produced by different individuals in a population.
|
|
|
Polymerase chain reaction (PCR):
|
a three step process of denaturation, annealing, and elongation that is repeated numerous times, resulting in many copies of a segment of DNA
|
|
|
If you have an organism with 2 million base pairs, which of the following could be the first step that you use to sequence its genome?
|
create a genomic library
|
|
|
What is an adaptation?
|
a trait that improves the fitness of its bearer, compared to individuals without the trait
|
|
|
The lac promoter is weak; for it to be fully induced:
|
cyclic AMP and lactose must be present
|
|
|
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.
|
|
|
What concentrations of the substances below will allow the lac operon to be frequently transcribed?
|
Cyclic AMP must be high, lactose must be high
|
|
|
What three major lines of evidence did Darwin use to argue that species have changed through time?
|
Darwin’s three major lines of evidence that species change through time are that: i. fossils frequently resemble species found in the same area today, ii. many species have gone extinct, and iii. vestigial traits are common.
|
|
|
Which of the following is the best definition of Darwinian fitness?
|
Darwinian fitness is the ability of an individual to survive and reproduce.
|
|
|
Which of the following sequences is in the correct order for one cycle of PCR?
|
Denature DNA; anneal primers; extend primers.
|
|
|
Genetic map:
|
determination of the location of a gene using rates of recombination of genes on a chromosome.
|
|
|
Restriction enzymes could be used in which of the following forensic analyses?
|
DNA fingerprinting
|
|
|
The reason that the 6.5 feet of DNA in a typical human cell can be packed into a nucleus that is only a few micrometers in diameter is that
|
DNA is negatively charged, and histones are positively charged; and this close association allows them to be packed tightly together in nucleosomes.
|
|
|
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 what kind of population is random genetic drift most pronounced?
|
Drift is greatest in small populations
|
|
|
Which one of these attributes of cells allows insertion of a gene into a plasmid?
|
Endonucleases
|
|
|
Which of these is an example of natural selection?
|
Enzymes that are adapted to higher temperatures are found in fish that live in tropical oceans.
|
|
|
Estimating heritability of human traits such as IQ or height is more challenging than estimating heritability in plant traits such as height or flower size or traits such as height or intelligence in other animals. Why?
|
Estimating heritability of human traits such as IQ or height is challenging because it is unethical to raise humans in randomly selected environments
|
|
|
Why are mRNA sequences generally used in the study of genome sequences in eukaryotes?
|
Eukaryotes have a number of introns in their genes, so it is difficult to determine the coding regions.
|
|
|
Which of the following does NOT tend to promote speciation?
|
Gene flow
|
|
|
Which of the following counteracts reproductive isolation?
|
Gene flow
|
|
|
Which of these factors causes geographically proximal populations to look similar?
|
Gene flow
|
|
|
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.
|
|
|
Which of these events happen first?
|
HAT proteins provide an acetyl group to histones
|
|
|
Transposable elements:
|
have the ability to replicate themselves and to move from one location to another in a genome
|
|
|
Which of the following properties do you predict to be most critical to histone association with DNA?
|
Histones are positively charged.
|
|
|
Over time, the same bones in different vertebrates were put to different uses. This falls under the category of:
|
Homologous structures
|
|
|
Resistance to a wide variety of insecticides, fungicides, antibiotics, antiviral drugs, and herbicides has recently evolved in hundreds of insects, fungi, bacteria, viruses, and plants. Why?
|
Humans are altering the environments of these organisms, and the organisms are evolving by natural selection.
|
|
|
Cladistic methods of phylogenetics depend upon
|
identifying monophyletic groups based on shared, derived characters.
|
|
|
If a child has cystic fibrosis, a genetic disorder that affects the lungs, which of the following would be the best "gene therapy" for the child?
|
incorporating a functional gene into the DNA of the child using a virus
|
|
|
If the gene shown codes for production of growth hormone protein, which of the following would MOST LIKELY increase production of the hormone?
|
increased mRNA transcription
|
|
|
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
|
|
|
Which of the following scenarios illustrates heterozygote advantage?
|
Individuals heterozygous at a given locus are more fit than homozygous individuals.
|
|
|
Regulatory transcription factors:
|
influence the assembly of the basal transcription complex
|
|
|
A major function of the tumor suppressor protein p53 is to
|
Inhibit the transcription of genes that promote cell division.
|
|
|
Plasmids are very important tools in molecular biology. In the cases we examined, plasmids were used to:
|
insert daffodil genes in rice
|
|
|
If you have created a cDNA library of mRNA produced by a given cell type, what is the optimal next step in producing large numbers of the cDNA molecules that are coded for by each different mRNA?
|
insert the gene into a yeast or bacterial plasmid
|
|
|
Humans and pufferfish have a similar number of genes, yet the human genome is approximately nine times larger than the pufferfish genome. In what form is much of this extra DNA?
|
Introns
|
|
|
A probe
|
Is used to find a DNA sequence of interest.
|
|
|
Sickle-cell disease is a recessive genetic disorder in which hemoglobin is improperly synthesized. If you were searching for the gene involved in this disorder, which of the following would be the first step?
|
isolate mRNA from cells from the bone marrow and spleen, where red blood cells are synthesized, of an individual with sickle-cell anemia
|
|
|
If you were examining a group of individuals who were color-blind (an X-linked recessive trait where retinal cells do not detect all of the colors), which of the following would be most helpful in initial studies that are focused on finding the gene?
|
isolating mRNA from retinal cells
|
|
|
Why is genetic drift aptly named?
|
It causes allele frequencies to drift up or down, randomly.
|
|
|
Why isn’t inbreeding, or mating among relatives, considered an evolutionary mechanism?
|
It does not change allele frequencies.
|
|
|
What does it mean if an allele reaches "fixation"?
|
It has a frequency of 1.0
|
|
|
What is the effect of large numbers of regions of AT repeats on sequencing a genome?
|
It is difficult to determine the correct regions of overlap.
|
|
|
What does lac I do?
|
It makes the repressor protein
|
|
|
What evidence do biologists use to infer that a locus is part of a gene family?
|
Its sequence, structure, and composition are similar to another gene in the same genome.
|
|
|
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
|
|
|
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
|
|
|
Which of the following is an example of a compound that is NOT involved in negative control of its own production
|
lactose
|
|
|
Which of the following best describes gene flow:
|
Migration
|
|
|
Genetic diversity is required for natural selection to act, but natural selection can reduce or eliminate diversity. What forces restore or maintain diversity of a population?
|
Migration is an evolutionary force that restores or maintains diversity within a population.
|
|
|
Gene flow:
|
migration of individuals into a population. Over time, populations with high gene flow will resemble each other.
|
|
|
What is an important consequence of migration in natural populations?
|
Migration tends to reduce genetic differences among populations
|
|
|
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
|
|
|
What is alternative splicing?
|
mRNA processing events that lead to different combinations of exons being spliced together
|
|
|
Which evolutionary process is least important for conservation biologists concerned about the future direction of evolutionary change in endangered populations?
|
Mutation is not a major concern
|
|
|
What are four mechanisms that cause allele frequencies to change?
|
mutation, selection, migration, and genetic drift
|
|
|
Darwin proposed that the mechanism behind evolutionary change was:
|
Natural selection
|
|
|
Which of the following biological processes leads to adaptation?
|
natural selection
|
|
|
Lactose binding to the repressor protein is an example of
|
Negative control
|
|
|
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
|
|
|
For a biologist studying a small fish population in the lab, which Hardy-Weinberg condition is easiest to meet?
|
no gene flow
|
|
|
Vestigial traits and neutral changes in DNA sequences are good examples of:
|
nonadaptive traits
|
|
|
Which of the following is involved in transcription of prokaryotes, but NOT in eukaryotic transcription?
|
operators
|
|
|
Transgenic:
|
organisms that have been altered by genetic engineering technology.
|
|
|
What is the use of a cDNA library?
|
Particular cloned genes (in the form of cDNA) can be isolated from a cDNA library.
|
|
|
What is the primary difference between PCR and more traditional cloning procedures?
|
PCR eliminates the need for restriction enzymes, vectors and cells.
|
|
|
Proteins are often modified before they are functional. If these modifications do not occur, this would be a form of:
|
Post translational control
|
|
|
How would you use this method to test for strains of E. coli that are susceptible to the effects of the antibiotic Cipro?
|
Press a velvet block onto a master plate without Cipro, and then plate the replica plate on medium with Cipro
|
|
|
Assume that you are a researcher who is looking to see which of the sequences in this microarray may contain the gene that codes for the production of a specific protein hormone in the human ovary. How would you produce the labeled cDNA’s used to probe the microarray?
|
produce an mRNA sequence inferred from the amino acid sequence of the protein hormone, and use a solution of radioactive nucleotides and reverse transcriptase to produce the labeled cDNA
|
|
|
Which of the following regulatory elements is matched correctly to its chemical composition?
|
promoter-proximal element; DNA
|
|
|
Genetic drift:
|
random changes in allele frequencies.
|
|
|
Genetic drift is an evolutionary process involving:
|
Random factors
|
|
|
Inbreeding violates Hardy-Weinberg equilibrium by:
|
reducing genetic variation
|
|
|
Extracellular glucose inhibits transcription of the lac operon by:
|
reducing the levels of intracellular cAMP
|
|
|
Stabilizing selection:
|
reduction in the extreme conditions of a trait for a population.
|
|
|
Which of these is tissue specific?
|
Regulatory proteins
|
|
|
STAT’s are a form of
|
Regulatory transcription factors
|
|
|
In eukaryotes, why are certain genes expressed only in certain types of cells?
|
Regulatory transcription factors vary from cell to cell.
|
|
|
To create a viral vector for delivery of genes into mammalian cells, the virus must be engineered to:
|
remove select viral genes and add the mammalian genes to be delivered
|
|
|
Genetic engineering became possible after the discovery of which of the following compounds?
|
restriction enzymes and ligase
|
|
|
Which of the following is an application of recombinant DNA technology?
|
rice plants that produce rice with ß-carotene
|
|
|
Which statement restates the fact that rifampin resistance in Mycobacterium tuberculosis is an adaptation?
|
Rifampin resistance is a heritable trait that increases fitness of individuals compared to susceptible individuals.
|
|
|
A molecular biologist studying fungi discovers a gene family that is similar to a gene family known in the fruit fly. If she wants to determine whether the fungi and fruit-fly gene families are analogous or homologous, she should:
|
See if organisms in lines that branched off between fungi and insects have similar gene families.
|
|
|
What is the only evolutionary mechanism that leads to adaptation?
|
selection
|
|
|
Which of the following best describes pseudogenes?
|
Sequences of DNA that are similar to a functional gene, but do not produce a product
|
|
|
What are minisatellites and microsatellites?
|
short and simple repeated sequences in DNA
|
|
|
Which of the following is NOT involved in the initiation of transcription in eukaryotes?
|
sigma protein
|
|
|
Parasitic species tend to have simple morphologies. Which of the following statements best explains this observation?
|
Simple morphologies have been naturally selected for in most parasites.
|
|
|
Plasmids:
|
small piece of circular DNA in bacteria distinct from the bacterial circular chromosome
|
|
|
What are minisatellites and microsatellites?
|
small, extrachromosomal loops of DNA similar to plasmids
|
|
|
Which of the following is a statement of the law of succession?
|
Species in the fossil record were succeeded, in the same region, by similar species.
|
|
|
How are STAT’s altered to cause cancer?
|
STAT’s are protein dimers that cannot be separated, enhancing cell division
|
|
|
One such source was studies of retrovirus replication. What aspect of a common cloning procedure makes direct use of this knowledge?
|
synthesizing cDNAs
|
|
|
Which of the following shown proteins have analogous functions in eukaryotes and in E. coli?
|
TATA binding protein and sigma protein
|
|
|
Which of these regulatory elements is physically located closest to a gene that is to be transcribed?
|
TATA box/promoter
|
|
|
The eukaryotic protein that functions most like the bacterial sigma factor is:
|
TATA-binding protein
|
|
|
What two major components comprise the core transcription complex?
|
TFIID and the RNA polymerase complex
|
|
|
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
|
|
|
The Hardy-Weinberg principle acts as a null model because it describes the relationship between allele and genotypic frequencies under what circumstances?
|
The circumstance occurs when none of the four evolutionary forces is acting and mating is random.
|
|
|
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.
|
|
|
What is chromatin?
|
the DNA-protein complex found in eukaryotes
|
|
|
In an individual cell in a eukaryotic, multicellular organism
|
the expression of specific genes can be turned on and off by compounds secreted by cells adjacent to the cell.
|
|
|
Which of these statements is TRUE?
|
The fine tuning of the universe is evidence for intelligent design.
|
|
|
What does it mean to say that a genetic marker and a disease gene are closely linked?
|
The marker and the disease gene are in close physical proximity and tend to be inherited together.
|
|
|
Which of the following is NOT a claim promoted by creationists when objecting to the theory of evolution by natural selection?
|
The mechanism by which an offspring inherits a trait from parents is unknown.
|
|
|
What does the lateral transfer of genes refer to?
|
the movement of genes from one species to another
|
|
|
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.
|
|
|
Why have soapberry bugs feeding on nonnative hosts evolved shorter beaks than those feeding on their native host plant?
|
The nonnative host species have smaller fruits; natural selection favors bugs with a shorter beak length on these hosts.
|
|
|
Scientists studying the “normal,” benign E. coli and the pathogenic E. coli strain O157:H7 have made which of the following determinations?
|
The O157:H7 strain has gene sequences that are similar to Shigella bacteria that are not found in the benign strain.
|
|
|
Transformation:
|
the process in which a host cell takes in foreign DNA from a vector.
|
|
|
Recombinant DNA
|
the process of using restriction enzymes and plasmids to make novel DNA combinations.
|
|
|
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.
|
|
|
A current view of how the human and chimpanzee can share most of their nucleotide sequence yet exhibit significant phenotypic differences is:
|
The relatively few sequence differences affect regulatory sequences and proteins.
|
|
|
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.
|
|
|
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 Sigma factor in prokaryotes is analogous to the _____ in eukaryotes.
|
The TATA binding protein
|
|
|
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
|
|
|
The enormous complexity in initiating eukaryotic transcription seems at first glance to be wasteful. What is one plausible reason for requiring so many different proteins to assemble on a large array of DNA sequences in order to initiate transcription?
|
The use of large numbers of proteins and regulatory sequences in DNA opens many possibilities for the sophisticated gene regulation required by eukaryotes.
|
|
|
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 following is a characteristic common to inbreeding and sexual selection?
|
They are both forms of nonrandom mating
|
|
|
Why are homologous traits similar?
|
They are derived from a common ancestor.
|
|
|
Which of the following statements about enhancers is correct?
|
They are found in a variety of locations, and are active in any orientation.
|
|
|
Why are the loci involved in lactose metabolism considered an operon?
|
They are under the control of the same promoter
|
|
|
What do restriction enzymes do?
|
They cut DNA at specific sites known as recognition sequences
|
|
|
Which of the following is NOT true about eukaryotic regulatory sequences?
|
They have the same function in different cell types.
|
|
|
Monod found mutant E. coli that were unable to concentrate the lactose-like molecule TMG. What is the defect in these cells?
|
They lack a functional copy of galactoside permease
|
|
|
What are plasmids used for?
|
To insert a gene in DNA
|
|
|
Genes for enzymes in the glycolytic pathway are expressed constitutively. What does this mean?
|
Transcription occurs constantly
|
|
|
Prokaryotes and Eukaryotes share one method of gene regulation. Which of the following is common to both types of cells?
|
Transcriptional control
|
|
|
Translation of E. coli sugar metabolism genes
|
turn on or off, depending on the sugars present in the gastrointestinal tract
|
|
|
Imagine you’re studying regulation of a set of genes involved in cell-wall synthesis. You isolate mutations that alter the regulation of these genes and find that one of these regulatory mutations causes the cell-wall synthesis genes to be expressed at much higher than normal levels. At first, you propose that the regulatory mutation must increase the activity of the normal regulatory gene product. Instead, you find that this mutation is a so-called loss-of-function mutation, one that prevents expression of the gene product. From these results, you can conclude that the cell wall synthesis genes are:
|
under negative control
|
|
|
Dideoxy sequencing:
|
use of stop nucleotides to determine the exact sequences of bases in a DNA fragment.
|
|
|
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 that could encode the amino acid sequence, and use them to design a probe.
|
|
|
Heritability quantifies the proportion of variation in a population that is due to what?
|
variation in the genetic makeup of individuals
|
|
|
When does vicariance occur?
|
when a large, continuous population is fragmented into isolated subpopulations
|
|
|
When does sexual selection occur?
|
when individuals experience differential success in obtaining mates
|
|
|
When does speciation occur?
|
when populations become isolated by lack of gene flow, then diverge as a result of mutation, drift, and selection
|
|
|
Can a biologist test the four postulates of evolution by natural selection when the alleles responsible for variation are not known, or the molecular mechanism of adaptation has not been identified?
|
Yes, a biologist must determine whether the trait under investigation is heritable. This can be determined experimentally for quantitative traits
|
|
|
Genetic engineering techniques have developed by borrowing knowledge from unexpected sources. One such source was studies of retrovirus replication. What aspect of a common cloning procedure makes direct use of this knowledge?
|
Using retroviruses as vectors to carry genes into bacterial cells
|
|
|
In the context of genetic engineering, plasmids are used as vectors. This means that plasmids allow for:
|
transfer of foreign genes into a cell
|
|
|
Because dideoxy sequencing is based on the chain termination, why are normal deoxynucleotides also included in the reaction?
|
to allow production of a full range of synthesis products that terminate at every occurrence of a particular base
|
|
|
The basic idea of using RFLPs to map the location of a disease gene boils down to:
|
creating a genetic map using biochemical markers, such as the presence or absences or enzyme activity, and correlating these markers with the presence or absences of a disease
|
|
|
Which step in Southern blotting allows an investigator to identify a particular DNA fragment that is present within a complex mixture of fragments?
|
hybridization with a labeled probe
|
|
|
The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid 1700s. They do not marry with memeberse outside their own immediate community. Thoday, the Dunkers are genetically unique and differ in gene frequences, at many loci, fro all other populations including their original homeland. Which of the following likely explains the genetic uniqueness of this population?
|
Founder Effect and Genetic Drift ( isolated )
|
|
|
Full induction of the lac operon occurs when:
|
lactose levels are high and glucose levels are low
|
|
|
You've treated E coli cells wit hUV light, plated the cells on glucose cointaining medium, and allowed the cells to grow into colonies. Now using this master plate you prepare two replica plates, one on medium containing only glucose and the other on medium containing only lactose as an energy source. Both replica plates are sprayed with ONPG. The vast majority of colonies are white on the glucose containing plates and yellow on the lactose containing plates, but you discover a single cology that is yellow on both types of plates. At this point you suspect this rare colony contains...
|
a mutation in the lac I gene
(makes the repressor if its is working, it eats and eats so it will be yellow no matter where it goes) |
|
|
Imagine that you discover a baterial operon involved in the synthesis of vitamin B12 (product). This operon is regulated by a repressor protein that binds to an operator sequences. Vitamin B12 is the allosteric effector of the repressor - the molecule that binds to the repressor to regulate its activity. Predict how vitamin B12 will influence repress activity.
|
When bitamin B12 binds to the repressor the repressor binds to the operator (to stop transcription)
|
|
|
According to the steric hindrance (structure binds to dna) 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
|
|
|
What feature of the repressor protein accounts for the dyand symmetry of each operator of the lac operon?
|
The DNA binding domains of the repressor function as dimers
|
|
|
How does a regulatory protein that binds to a specific DNA sequence recognize this sequence?
|
The regulator protein detects the portion of the base pairs that projects into the grooves of double-stranded DNA
|
|
|
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
|
|
|
Eukaryotes utilize at least one method to control teir gene expression that is not seen in bacteria. These method are
|
1) control of chromatin remodeling and 2) control of RNA processing, especially splicing
|
|
|
Imagine you've isolated a yeast mutant that contains a constitutively (constantly) active histone deacetylase. What phenotype do you predict for this mutant?
|
The mutant will show generally low levels of gene expression
|
|
|
The primary difference between an enhancer and a promoter-proximal element is that:
|
enhances are at considerable distances from the promoter, promoter-proximal elements are close to the promoter
|
|
|
Fundamentally, what makes one cell different from another in a multicellular eukaryote
|
the different cells contain different sets of regulatory proteins
|
|
|
If a mutation deleted one copy of a proto-oncogene, this would
|
not make the cell more likely to divide uncontrollably
|
|
|
a major function of the tumor suppressor protein p53 is to:
|
activate the transcription of genes that inhibit cell division
|
