Chapter 19-21
Describe the basic components of a virus.
*Capsid *Capsomers *DNA: single or double stranded *RNA: single or double stranded *Enveloped/non-enveloped
Which of the following human diseases is caused by a virus that requires reverse transcriptase to transcribe its genome inside the host cell?
AIDS
Which of the following statements correctly describes one characteristic of a multigene family?
A multigene family includes genes whose sequences are very similar and that probably arose by duplication.
Why is sequencing an entire genome, such as that of C. elegans, a nematode, important for genetic research?
A sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates.
Which of the following statements best reflects what we know about how the flu virus moves between species?
An animal such as a pig is infected with more than one virus, genetic recombination occurs, the new virus mutates, the virus is passed to a new species such as a bird, and the virus mutates again and can now be transmitted to humans.
What is difference between an epidemic and a pandemic?
An epidemic is restricted to a local region; a pandemic is global.
Use the following information to answer the question. The figure shows a diagram of blocks of genes on human chromosome 16 and the locations of blocks of similar genes on four chromosomes of the mouse. Which of the following statements describes the result of the movement of these blocks?
Chromosomal translocations have moved blocks of sequences to other chromosomes.
Reproductive cloning of human embryos is generally considered unethical. However, on the subject of therapeutic cloning, there is a wider divergence of opinion. Which of the following statements provides a likely explanation?
Cloning to produce embryonic stem cells may lead to great medical benefits for many.
Describe prions and explain how they cause disease.
Prions: proteins that get misfolded and cannot be broken down Prions cause disease because they aggregate into a complex that converts normal proteins into prions that make their way to the brain, misfolding proteins and that causes cell death in the brain.
Which of the following tools of DNA technology is incorrectly paired with its use?
DNA ligase—cutting DNA, creating sticky ends of restriction fragments
Which of the following techniques would be most appropriate to test the hypothesis that humans and chimps differ in the expression of a large set of shared genes?
DNA microarray analysis
Describe DNA microarrays and explain why it is useful.
DNA microarrays: mRNA is isolated from tissue sample and color-coded with fluorescent tags and used to make cDNA. cDNA binds to complimentary base pairs in each of the spots on the array. Look for color difference. Useful because it lets you look at all the RNA in a genome at one time
What is the function of reverse transcriptase in retroviruses?
It uses viral RNA as a template for DNA synthesis.
Which of the following is not true of cDNA produced using human brain tissue as the starting material?
It was produced from pre-mRNA using reverse transcriptase.
Describe gel electrophoresis and explain why it is useful.
Gel electrophoresis: Uses a gel made of polymer to separate a mixture of nucleic acids or proteins based on size, charge, or other physical properties Useful because it is used to separate and visualize fragments produced
Describe gene annotation and explain its importance.
Gene annotation: identification of protein-coding genes within DNA sequences in a database Importance: Gene annotation helps give an insight of what genes do in the body
Studies in knockout mice have demonstrated an important role of the FOXP2 transcription factor in the development of vocalizations. Recent sequence comparisons of the FOXP2 gene in Neanderthals and modern humans show that while the DNA sequence may be different, the protein sequence it codes for is identical. Which of the following conclusions might logically be inferred from this information?
Human and Neanderthal vocalizations may have been more similar than previously thought.
Which of the following statements is a correct representation of gene density?
Humans have ~20,000 protein-encoding genes in a 3,000 Mb.
In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. Why is this the case?
Nonidentical genes produce different versions of globins during development.
Describe RNA-seq and explain why it is useful.
RNA-seq: Isolate mRNA and cut them into small fragments and are reverse transcribed, then are sequenced. Then map the RNA to the genome and look for an abundance. Useful because this should provide a grand view of how genes interact to form an organism and maintain its vital systems
Why do RNA viruses appear to have higher rates of mutation?
Replication of their genomes does not involve proofreading.
Why do typappear to have higher rates of mutation?
Replication of their genomes does not involve proofreading.
Describe the two bacterial defenses against phages.
Restriction enzymes: proteins that destroy DNA or RNA before it can make proteins and assemble itself CRISPR-Cas system: if cell survives infection, it can block any attempt of the same type of phase to reinfect it, RNAs are cut into pieces and bound by Cas proteins
Why might using retroviral vectors for gene therapy increase the patient's risk of developing cancer?
Retroviral vectors integrate recombinant DNA into the genome in ways that may misregulate the expression of genes at or near the site of integration.
In large scale, genome-wide association studies in humans, what types of genetic markers do researchers look for?
SNPs where one allele is found more often in persons with a particular disorder than in healthy controls
How do transposable elements and short tandem repeats (STRs) differ?
STRs make up only a small percentage of a given genome while transposable elements often make up larger parts of a given genome.
Which of the following statements correctly describes how RNA interference (RNAi) silences selected genes?
Synthetic double-stranded RNA molecules trigger the breakdown of a gene's messenger RNA.
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. The new phages produced would have?
T4 protein and T4 DNA.
What information is critical to the success of polymerase chain reaction (PCR) itself?
The DNA sequence of the ends of the DNA to be amplified must be known.
A person is most likely to recover from a cold due to viral infection if the infected cells are able to perform which of the following processes?
The cells can undergo normal cell division.
A researcher is using adult stem cells and comparing them to other adult cells from the same tissue. Which of the following findings is likely from this comparison?
The cells from the two sources exhibit different patterns of DNA methylation.
Why is sequencing of eukaryotic genomes more difficult than sequencing genomes of bacteria or archaea?
The large size of eukaryotic genomes and the large amount of eukaryotic repetitive DNA make sequencing difficult.
A microarray is a tool used in genetic research to determine the mRNAs being produced in a particular tissue, and their relative level of expression. Known genes can therefore be assayed for their expression in different situations. One use of the technology is in cancer diagnosis and treatment. If a known gene functions as a tumor suppressor, predict which of the following pieces of evidence would be most useful in diagnosis of a cancer due to a mutation in this tumor-suppressor gene.
The mRNAs for the targeted tumor suppressor sequence are not being produced.
Which of the following statements accurately describes the lysogenic cycle of lambda (λ) phage?
The phage genome is integrated in the host chromosome where it is replicated along with the host genome.
If a viral host cell has a mutation that interferes with the addition of carbohydrates to proteins in the Golgi apparatus, which of the following processes could likely result?
The viral envelope proteins would not have glycoproteins added to them and might not arrive at the host plasma membrane.
A researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). The cell contents are left in a covered test tube overnight. The next day this mixture is sprayed on tobacco plants. What would you expect to happen to the plants that were sprayed with the mixture?
The plants would develop the typical symptoms of TMV infection.
Which of the following statements correctly describes vaccines and how they help prevent viral infection?
Vaccines are inactive versions of a virus that stimulate an immune reaction in a person.
Which of the following statements correctly describes one of the characteristics of alternative splicing in vertebrate genomes?
Vertebrate genomes can produce more than one polypeptide from a single gene.
Which of the following descriptions correctly identifies the main structural differences between viruses with envelopes and viruses without envelopes?
Viruses with envelopes have a phospholipid membrane outside their capsid, whereas viruses without envelopes do not have a phospholipid membrane.
The first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent. Why was this the case with this clone?
X chromosome inactivation in the embryo is random and produces different patterns.
Which of the following statements is correct regarding viral infections in plants?
They can spread within a plant via plasmodesmata.
In a comparison of two DNA sequences found in the same location on homologous chromosomes, one of the homologs carries the sequence 5′-AACTACGA-3′, and the other homolog carries the sequence 5′-AACTTCGA-3′. Within a population, you discover that each of these sequences is common. Which of the following statements correctly describes theses sequences?
They contain a SNP that may be useful for genetic mapping.
Describe methods that can be used to treat viral infections and explain their limitations.
Vaccinations are given to prevent viruses by stimulating the immune system to mount defenses against the harmful pathogen, but they are not a treatment Antiviral drugs can help treat, but not cure viral infections by inhibiting synthesis of viral DNA and interfering with viral assembly Interferons interfere with replications of viruses
Which of the following statements correctly describes one characteristic of retrotransposons?
They use an RNA molecule as an intermediate in transposition.
Which of the following statements describes one of the technical reasons why gene therapy is problematic in humans?
Transferred genes may not have appropriately controlled activity.
A principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria is that ________.
bacteria cannot remove eukaryotic introns
When gene duplication occurs to its ultimate extent by doubling all genes in a genome, which of the following results has occurred?
creation of a polyploid
A population of viruses with similar characteristics is called a ________.
class
A recent study compared the Homo sapiens genome with that of Neanderthals. The results of the study indicated that there was a mixing of the two genomes at some period in evolutionary history. Which of the following potential discoveries of additional data might be consistent with this hypothesis?
a few modern H. sapiens with some Neanderthal sequences
Using modern techniques of sequencing by synthesis and the shotgun approach, sequences are assembled into chromosomes by ________.
computer analysis looking for sequence overlaps
In many ways, the regulation of the genes of a particular group of viruses will be similar to the regulation of the host genes. Therefore, which of the following regulation mechanisms would you expect of the genes of a bacteriophage?
control of more than one gene in an operon
For a particular microarray assay (DNA chip), cDNA has been made from the mRNAs of a dozen patients' breast tumor biopsies. Which of the following types of evidence will researchers be looking for in order to determine if the cells are cancerous?
a pattern shared among some or all of the samples that indicates gene expression differing from control samples
In DNA technology, the term vector can refer to
a plasmid used to transfer DNA into a living cell.
Which of the following types of genes or gene families may be created by mutations that occur in one member of a gene pair that arose from gene duplication?
a pseudogene, a gene with a new function, and a gene family with two distinct but related members
Plants are more readily manipulated by genetic engineering than are animals because
a somatic plant cell can often give rise to a complete plant.
Which of the following processes helps bacterial cells protect their own DNA from restriction enzymes (endonucleases)?
adding methyl groups to adenines and cytosines
Emerging viruses arise by
all of the above
Emerging viruses arise by
all of the above mutation of existing viruses. the spread of existing viruses to new host species. the spread of existing viruses more widely within their host species.
RNA viruses require their own supply of certain enzymes because
host cells lack enzymes that can replicate the viral genome.
Several of the different globin genes are expressed in humans, but at different times in development. Which of the listed mechanisms could allow for this?
differential gene regulation over time
Homeotic genes
encode transcription factors that control the expression of genes responsible for specific anatomical structures.
Bioinformatics can be used to scan for short sequences that specify known mRNAs, called ________.
expressed sequence tags
Which of the following processes correctly describes gene annotation in bioinformatics?
finding transcriptional start and stop sites, RNA splice sites, and ESTs in DNA sequences
DNA technology has many medical applications. Which of the following is not done routinely at present?
gene editing by the CRISPR-Cas9 system in viable human embryos to correct genetic diseases
Which of the following characteristics, structures, or processes is common to both bacteria and viruses?
genetic material composed of nucleic acid
Which of the following processes can be effective in preventing the onset of viral infection in humans?
getting vaccinated to certain viruses
Use the figure to answer the question. In the figure, at the arrow marked II, what enzyme is being utilized?
host cell DNA polymerase
Effective antiviral drugs are usually associated with which of the following properties?
interference with viral replication
Which of the following processes is most like the formation of identical twins?
organismal cloning
Many identical copies of genes cloned in bacteria are produced as a result of which of the following processes?
plasmid and bacterial cell reproduction
A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo (a bird). To compare a specific region of the DNA from a sample with DNA from living birds, which of the following would be most useful for increasing the amount of dodo DNA available for testing?
polymerase chain reaction (PCR)
Expression of a cloned eukaryotic gene in a bacterial cell involves many challenges. The use of mRNA and reverse transcriptase is part of a strategy to solve the problem of
post-transcriptional processing.
One possible use of transgenic plants is in the production of human proteins, such as vaccines. Which of the following issues is a possible hindrance that must be overcome in order for this process to work properly?
prevention of transmission of plant allergens to the vaccine recipients
A current view of how the human and chimpanzee can share most of their nucleotide sequences yet exhibit significant phenotypic differences is that many of the most important sequence differences alter ________.
regulatory sequences
What is metagenomics?
sequencing DNA from a group of species from the same ecosystem
During which of the following processes does exon shuffling occur?
meiotic recombination
The virus genome and viral proteins are assembled into virus particles during which of the following parts of the reproductive cycle?
the lytic cycle only
The host range of a virus is determined by ________.
the proteins on its surface and that of the host
What can proteomics reveal that genomics cannot?
the set of proteins present within a cell or tissue type
The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is ________.
the spread of viruses from trees and tall plants to bushes and other smaller plants, and horizontal transmission is the spread of viruses among plants of similar size
Fragments of DNA have been extracted from the remnants of extinct woolly mammoths, amplified, and sequenced. How can these fragments of DNA now be used?
to better understand the evolutionary relationships among members of related taxa
RNAi methodology uses double-stranded pieces of RNA to trigger breakdown of a specific mRNA or inhibit its translation. For which of the following processes might this technique be useful?
to decrease the production from a harmful mutated gene
For which of the following processes can dideoxyribonucleotides be used?
to sequence a DNA fragment
The difference between vertical and horizontal transmission of plant viruses is that vertical transmission is ________.
transmission of a virus from a parent plant to its progeny, and horizontal transmission is one plant spreading the virus to another plant
Describe the replication of RNA and DNA viruses.
1) Virus enters cell 2) Uncoats 3) DNA gets to the nucleus and inserts itself into host and goes through replication, transcription, and translation making proteins. RNA sense strand immediately goes through replication and produces proteins. The RNA antisense strand brought in proteins with it that makes mRNA and turn it into a sense strand. It goes through replication and produces proteins 4) They assemble 5) Exit cell
Use the following figure and information to answer the question(s) below. Cells were infected with approximately 1,000 copies of either virus A or virus B at the 0 time point. At five-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined. Using the data in the figure, how long does it take for virus A to go through one lytic cycle?
45 minutes
Which of the following sequences is most likely to be cut by a restriction enzyme?
5′-AATATT-3′ 3′-TTATAA-5′
Use the following figure and information to answer the question. Cells were infected with approximately 1,000 copies of either virus A or virus B at the 0 time point. At five-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined. Using the data in the figure, how long does it take for virus B to go through one lytic cycle?
60 minutes
Use the following figure and information to answer the question. Cells were infected with approximately 1,000 copies of either virus A or virus B at the 0 time point. At five-minute intervals, a sample of the virus and cell mixture was removed. The intact cells were removed from the sample, and the number of viruses per milliliter of culture was determined. Using the data in the figure, how long does it take for virus B to go through one lytic cycle?
60 minutes
Why is it so important to be able to amplify DNA fragments when studying genes?
A gene may represent only a millionth of the cell's DNA.
Which of the following characteristics is typical of the lytic cycle of a bacteriophage?
A large number of phages are released at a time.
In recent times, it has been shown that adult cells can be induced to become pluripotent stem cells (iPS). To make this conversion, what has been done to the adult cells?
A retrovirus is used to introduce four specific master regulatory genes.
Use the figure to answer the following question. The segment of DNA shown in the figure has restriction sites I and II, which create restriction fragments A, B, and C. Which of the gels produced by electrophoresis best represents the separation and identity of these fragments?
C A B
Comparisons of DNA sequences within the human species have revealed many variations. Which of the following variations involves duplication of relatively long stretches of DNA?
CNVs
Discuss comparative genomics and explain the information that can be gained.
Compares genes of species to different species Allows us to discover functionalities of genes and proteins based off similarities Compares interspecies (same species different individuals) Helps identify mutations and allows us to see the errors one individual may have Compare healthy genes to unhealthy genes within the same individual You can see where errors have occurred
A sequence database such as GenBank could be used to carry out which of the following processes?
Construct a tree to determine the evolutionary relationships between various bird species.
Why might the cricket genome have eleven times as many base pairs as that of Drosophila melanogaster?
Crickets must have more noncoding DNA.
What is the most favorable characteristic of retroviruses that makes them useful in gene therapy applications?
DNA copies of retroviral genomes become integrated into the genome of the infected cell.
Describe DNA duplications, rearrangements, and mutations and explain how they can lead to genome evolution.
DNA duplications: incorrect pairing of 2 homologs during meiosis results in crossing over of misaligned nonsister chromatids and nature changes copy of allele DNA rearrangements: thought to contribute to the generation of new species DNA mutations: differences between the genes arise from accumulation mutations Lead to genome evolution: Beneficial mutations can lead to biological fitness and eventually population evolution.
Which of the following can be duplicated in a genome?
DNA sequences, chromosomes, or sets of chromosomes
Describe DNA sequencing and explain why it is useful.
DNA sequencing: Genomic DNA is fragmented and each fragment is isolated with a bead. Use PCR 10^6 copies are made and attached to 5' end. Beads are then placed in well with DNA polymerase and primers. Solutions of each 4 nucleotides are added to all wells and then washed off. Entire process is repeated. Useful because technology is used to determine the order of the nucleotide sequence
Which of the following statements correctly describes one of the main differences between embryonic stem cells and adult stem cells?
Embryonic stem cells can give rise to all cell types in the organism, and adult stem cells cannot.
Describe exon duplicate and exon shuffling and explain how they can lead to genetic changes.
Exon duplication: duplication of exons within the same gene to give rise to the subsequent exon Exon shuffling: errors in meiotic recombination lead to some mixing and matching of exons within a gene or between 2 nonallelic genes Lead to genetic changes: Errors that are beneficial to the organism can lead to biological fitness that will be passed down to the child then there children's children, eventually leading to a gene change within the population of an organism.
Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
GGCC CCGG
Which of the following sequences in double-stranded DNA is most likely to be recognized as a cutting site for a restriction enzyme?
GGCC- CCGG
Describe how to clone a gene using bacteria and explain why it is useful.
Gene inserted into plasmid and restriction enzyme to cut open the vector plasmid. Use restriction enzyme to cut out gene of interest leaving sticky ends. Complimentary base pairing occurs and ligate links the fragments together. Plasmid is put into bacteria cell by transformation. Bacteria grown in culture to form a clone of cells called "cloned" gene of interest. Useful because it can alter bacteria for cleaning up toxic waste
One predicted aspect of climate change is that climates, including precipitation and temperature, over most of Earth will become more variable. Which of the following is a good strategy for genetically engineering crops if this is true?
Genetically engineer several genotypes within single crop types.
Describe genome size, gene number, and gene density and explain their impact on the complexity of an organism.
Genome size: range from 1 to 6 million base pairs in bacteria, eukaryotic genomes tend to be larger Gene number: 1,500-7,500 genes in free-living bacteria, about 5,000 genes in unicellular fungi, and at least 40,000 in multicellular eukaryotes Gene density: humans and mammals have lowest gene density in a given length of DNA and multicellular eukaryotes have many introns within genes and a large amount of noncoding DNA between genes Impact: Gene size, number, and density do not impact complexity.
Discuss genomics, proteomics, and bioinformatics and explain their impact on science.
Genomics: looking at all the genes of an organism at one time Proteomics: studying large sets of proteins and their properties Bioinformatics: taking data from experiment and using a computer to figure it out Impact: Took us form looking at one protein to looking at all the genes to see what is going on in a cell
Why do scientists consider HIV to be an emerging virus?
HIV suddenly became apparent and widespread in the 1980s.
Which of the following processes within viral replication is the greatest source of genetic variation in RNA virus populations?
High mutation rate due to lack of proofreading of RNA genome replication errors.
Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for the domain of a protein that binds to DNA in a regulatory developmental process. Which of the following statements is therefore correct regarding homeotic genes?.
Homeotic genes are selectively expressed as an organism develops
Homeotic genes contain a homeobox sequence that is highly conserved among very diverse species. The homeobox is the code for the domain of a protein that binds to DNA in a regulatory developmental process. Which of the following statements is therefore correct regarding homeotic genes?
Homeotic genes are selectively expressed as an organism develops.
Refer to the treatments listed to answer the question. You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, or prion. You have four methods at your disposal to analyze the substance and determine the nature of the infectious agent. I. Treat the substance with enzymes that destroy all nucleic acids, and then determine whether the substance is still infectious. II. Filter the substance to remove all elements smaller than what can be easily seen under a light microscope. III. Culture the substance on nutritive medium, away from any plant cells. IV. Treat the sample with proteases that digest all proteins, and then determine whether the substance is still infectious. If you already know that the infectious agent was either a virus or a prion, which method(s) listed above would allow you to distinguish between these two possibilities?
I only
Suppose that a researcher is successful at producing induced pluripotent stem cells (iPS) for replacement of pancreatic insulin-producing cells for people with type 1 diabetes. Which of the following could still pose problems for this individual? I. the possibility that, once introduced into the patient, the iPS cells produce non-pancreatic cells II. the failure of the iPS cells to take up residence in the pancreas III. the inability of the iPS cells to respond to appropriate regulatory signals
I, II, and III
Use the figures to answer the question. Which of the three types of viruses shown in the figure would you expect to include a capsid(s)?
I, II, and III
Bioinformatics includes ________. I. using computer programs to align DNA sequences II. creating recombinant DNA from separate species III. developing computer-based tools for genome analysis IV. using mathematical tools to make sense of biological systems
I, III, and IV
Refer to the treatments listed to answer the question. You isolate an infectious substance capable of causing disease in plants, but you do not know whether the infectious agent is a bacterium, virus, or prion. You have four methods at your disposal to analyze the substance and determine the nature of the infectious agent. I. Treat the substance with enzymes that destroy all nucleic acids, and then determine whether the substance is still infectious. II. Filter the substance to remove all elements smaller than what can be easily seen under a light microscope. III. Culture the substance on nutritive medium, away from any plant cells. IV. Treat the sample with proteases that digest all proteins, and then determine whether the substance is still infectious. If you already know that the infectious agent was either bacterial or viral, which method(s) listed above would allow you to distinguish between these two possibilities?
II or III
What is the most logical sequence of steps for splicing foreign DNA into a plasmid and inserting the plasmid into a bacterium? I. Transform bacteria with a recombinant DNA molecule. II. Cut the plasmid DNA using restriction enzymes (endonucleases). III. Extract plasmid DNA from bacterial cells. IV. Hydrogen-bond the plasmid DNA to non-plasmid DNA fragments. V. Use ligase to seal plasmid DNA to non-plasmid DNA.
III, II, IV, V, I
The final step in a Sanger DNA sequencing reaction is to run the DNA fragments on a gel. What purpose does this serve?
It separates DNA fragments generated during the sequencing reaction based on one-nucleotide differences in their size.
Use the following information to answer the question. The herpes viruses are important enveloped DNA viruses that cause disease in vertebrates and in some invertebrates such as oysters. Some of the human forms are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can later reactivate, replicate again, and infect others. If scientists are trying to use what they know about the herpes simplex virus to devise a means of protecting other people from being infected, which of the following treatments would have the best chance of lowering the number of new cases of infection?
Interfere with new viral replication in preexisting cases of herpes simplex virus.
Use the following information to answer the question. The herpes viruses are important enveloped DNA viruses that cause disease in vertebrates and in some invertebrates such as oysters. Some of the human forms are herpes simplex virus (HSV) types I and II, causing facial and genital lesions, and the varicella zoster virus (VSV), causing chicken pox and shingles. Each of these three actively infects nervous tissue. Primary infections are fairly mild, but the virus is not then cleared from the host; rather, viral genomes are maintained in cells in a latent phase. The virus can later reactivate, replicate again, and infect others. If scientists are trying to use what they know about the herpes simplex virus to devise a means of protecting other people from being infected, which of the following treatments would have the best chance of lowering the number of new cases of infection?
Interfere with new viral replication in preexisting cases of herpes simplex virus.
Which of the following characteristics of Taq polymerase make it useful in the PCR process?
It is heat stable and can withstand the heating step of PCR.
Which of the following statements defines proteomics?
It is the study of the full protein set and its prop
Which of the following statements defines proteomics?
It is the study of the full protein set and its properties.
Describe lytic and lysogenic cycle of bacteriophages.
Lytic cycle: Virus injects its DNA into the bacteria, so now the bacteria has its own DNA and still has DNA from the actual bacteria. Now, the host DNA has been destroyed and falls apart due to the phage DNA directing it to do so, leaving only the DNA from the virus and undergoes replication and makes proteins. It then assembles and secretes proteins that weakens the cell wall causing the bacteria to lyse and release the phages. Lysogenic cycle: Virus injects its DNA into the bacteria, so now the the bacteria has its own DNA and still has DNA from the actual bacteria. Now, the DNA from the virus integrates itself into the chromosome of the host DNA. Every time the bacteria replicates, it passes its phage (prophase DNA) from generation to generation. At some point the host cell becomes stressed and goes through the lytic cycle
Will treating a viral infection with antibiotics affect the course of the infection?
No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes.
Describe PCR and explain why it is useful.
PCR: Heat DNA 95 degrees Celsius causing strands to separate, Cooling DNA causes polymerase to extend by incorporating nucleotides and amplifies 2 strands of DNA to multiple strands Useful because it can be used in crime cases to compare DNA and also for paternity tests
Pax-6 is a gene that is involved in eye formation in many invertebrates, such as Drosophila. Pax-6 is also found in vertebrates. A Pax-6 gene from a mouse can be expressed in a fly and the protein (PAX-6) leads to a compound fly eye. This information suggests which of the following characteristics of this gene?
Pax-6 is highly conserved and shows shared evolutionary ancestry.
In 2009, a flu pandemic was believed to have originated when viral transmission occurred from pig to human, thereby earning the designation "swine flu." Although pigs are thought to have been the breeding ground for the 2009 virus, sequences from bird, pig, and human viruses were all found within this newly identified virus. What is the most likely explanation of why this virus contained sequences from bird, pig, and human viruses?
Related viruses can undergo genetic recombination if the RNA genomes mix and match during viral assembly.
Describe in situ hybridization and explain why it is useful.
Situ hybridization: use fluorescent dyes attached to probes to identify the location of specific mRNAs in an intact organism by complimentary bonding Useful because it can be used in medical diagnostics to assess chromosomal integrity
Use the following information to answer the question. Poliovirus is an RNA virus of the picornavirus group, which uses its RNA as mRNA. At its 5′ end, the RNA genome has a viral protein (VPg) instead of a 5′ cap. This is followed by a non-translated leader sequence, and then a single long protein-coding region (~7,000 nucleotides), followed by a poly-A tail. Observations were made that used radioactive amino acids similar in structure to those that are found in viruses and other organisms. Short-period use of the radioactive amino acids result in labeling of only very long proteins, while longer periods of labeling result in several different short polypeptides. What conclusion is most consistent with the results of the radioactive labeling experiment?
The RNA is only translated into a single long polypeptide, which is then cleaved into shorter ones.
Humans have 23 pairs of chromosomes, and chimps have 24 pairs of chromosomes. What is the most likely explanation for these differences in human and chimp genomes?
The common ancestor of humans and chimps had 24 pairs of chromosomes. During human evolution, two human chromosomes fused end to end.
HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings?
The flu virus can be transmitted more easily from person to person than HIV.
Which of the following conclusions has led to the comparison between the number of human genes and those of other animal species?
The number of proteins expressed by the human genome is far greater than the number of its genes.
Which of the following characteristics of short tandem repeats (STRs) DNA makes it useful for DNA fingerprinting?
The number of repeats is highly variable from person to person or animal to animal.
If the sequence of a cDNA has matches with DNA sequences in the genome, then this genomic DNA could be described by which of the following statements?
The sequence codes for a protein.
Viruses use the host cell's machinery to make copies of themselves. However, some human viruses require a type of replication that humans do not normally have. For example, humans normally do not have the ability to convert RNA into DNA. How can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires?
The viral genome codes for specialized enzymes not found in the host cells.
In animals, what is the difference between reproductive cloning and therapeutic cloning?
Therapeutic cloning supplies cells for repair of diseased or injured organs.
Why is it more difficult to identify eukaryotic genes than prokaryotic genes using genomic techniques?
There are introns in eukaryotic genes.
Unequal crossing over during prophase I can result in one sister chromosome with a deletion and another with a duplication. A mutated form of hemoglobin, so-called hemoglobin Lepore, exists in the human population. Hemoglobin Lepore has a deleted series of amino acids. If this mutated form was caused by unequal crossing over, what would be an expected consequence?
There should also be persons whose hemoglobin contains two copies of the series of amino acids that is deleted in hemoglobin Lepore.
How have DNA microarrays made a huge impact on genomic studies?
They allow the expression of many or even all of the genes in the genome to be compared at once.
Why are yeast cells frequently used as hosts for cloning?
They are eukaryotic cells.
Which of the following statements supports the argument that viruses are nonliving
They do not carry out metabolic processes.
Which of the following statements supports the argument that viruses are nonliving?
They do not carry out metabolic processes.
Which of the following statements correctly describes one characteristic of genetically engineered plants?
They include transgenic rice plants that can grow in water more salty than seawater.
Describe transposable elements and explain how transposons and retrotransposons can move within a genome.
Transposable elements: Prokaryotes and eukaryotes have stretches of DNA that can move from one location to another within the genome Transposons move by means of a DNA intermediate and require a transposase enzyme where retrotransposons move by means of an RNA intermediate using a reverse transcriptase.
How do transposons and retrotransposons differ in how they move around in a genome?.
Transposons move by means of a DNA intermediate and retrotransposons move by means of an RNA intermediate
Which of the following statements correctly describes a difference between viruses and prions?
Viruses generally cause disease symptoms quickly, whereas prions generally take many years to cause disease symptoms.
Use the following information to answer the question. In an experiment, DNA from the linear form of the bacteriophage Lambda was cut into fragments using the restriction enzyme Hind III. Hind III cuts the Lambda DNA between the adenine nucleotides on the complimentary strands in a specific sequence, as indicated in the diagram, producing eight different size fragments. These fragments are then separated with an electrical current based on size after the DNA fragments are placed in a porous gel, a process called gel electrophoresis. Select an observation that best describes a correct aspect of the two processes of restriction digest and gel electrophoresis.
When separated on a gel, the pattern of DNA bands will be characteristic of those cut with Hind III; different restriction enzymes will not produce these same fragments.
Which of the following problems with animal cloning might result in premature death of the clones?
abnormal gene regulation due to variant methylation
Current analysis indicates that less than 2% of the human genome codes for proteins. Based on the systems approach employed by the ENCODE project, what percentage of the genome is estimated to be transcribed at some point in at least one cell type?
about 75%
Which of the following viruses would most likely have reverse transcriptase inside them?
an RNA-based lysogenic virus
Which of the following processes is an early step in the whole-genome shotgun approach to sequencing?
break genomic DNA at random sites
Biologists now routinely test for homology between genes in different species. If genes are determined to be homologous, how are they related to each other?
by descent from a common ancestor
In the form of gene therapy used successfully for severe combined immunodeficiency syndrome, SCID-X1, how is the genetic engineering of human cells achieved?
by isolating the patient's bone marrow cells, infecting them with genetically engineered viruses, and injecting them back into the patient's bone marrow
Transgenic mice are useful to human researchers because they ________.
can be valuable animal models of human disease
Which of the following events or characteristics accounts for someone who has had regular herpesvirus-mediated cold sores or genital sore flare-ups?
copies of the herpesvirus genome permanently maintained in host nuclei
Which of the following correctly lists the processes in order for one cycle of polymerase chain reaction (PCR)?
denature DNA; anneal primers; extend primers
Which of the following methods would be most successful in attempting to introduce a particular piece of DNA into an animal cell?
electroporation followed by recombination
Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?
exon shuffling
After finding a new medicinal plant, a pharmaceutical company decides to determine if the plant has genes similar to those of other known medicinal plants. What would annotation of the genome of this plant allow the company to determine?
identify genes and determine their functions
Which of the following processes uses labeled probes to visualize the expression of genes in whole tissues and organisms?
in situ hybridization
What are prions?
misfolded versions of normal proteins that can cause disease
Use the figure to answer the question. In the figure, when new viruses are being assembled at the point marked IV, what mediates the assembly?
no mediator is required; the new viruses self-assemble
Use the following information to answer the question. Organisms share many conserved core processes and features, including transcription and translation, using a uniform genetic code. Scientists have used these shared processes and features in biotechnology. For example, for the process of some transformations, a plasmid is constructed when a eukaryotic gene of interest is added with an antibiotic resistant gene such as beta-lactamase, which is used for ampicillin resistance. This plasmid is then inserted into a prokaryotic bacterial cell, such as E. coli, through a transformation process that leads to the production of the product protein from the eukaryotic organism. To culture the bacteria and obtain the protein product, the bacteria must grow. Select the appropriate condition to determine if the plasmid has entered the E. coli bacterial cell.
nutrient broth to which ampicillin has been added
Describe qRT-PCR and explain why it is useful.
qRT-PCR: Isolate RNA and put them in a test tube containing reverse transcription. Put nucleotides in test tube and it will make a copy of DNA. Put in RNAs with digest RNA. Add polymerase and primer to get DNA Useful to discover which tissue is producing a specific mRNA
A virus consisting of a single strand of RNA, which is reverse transcribed into complementary DNA, is referred to as a ________.
retrovirus
Which of the following enzymes is required to make complementary DNA (cDNA) from RNA?
reverse transcriptase
Which of the following types of viral genomes could be transcribed using reverse transcriptase?
ssRNA
Which of the following information or processes does gene therapy require?
the ability to introduce the normal allele into the patient
Some viruses can be crystallized and their structures analyzed. One such virus is yellow mottle virus, which infects beans. This virus has a single-stranded RNA genome containing about 6,300 nucleotides. Its capsid is 25-30 nm in diameter and contains 180 identical capsomeres. If the yellow mottle virus begins its infection of a cell by using its genome as mRNA, which of the following would you expect to be able to measure when analyzing the reproduction of this virus?
translation rate
Bioinformatics includes all of the following except
using DNA technology to combine DNA from two different sources in a test tube.
Based on the data in the Amino Acid Sequence Identity Table, which two members of the human globin gene family are the most divergent?
α1 and G?