Concept explainers
CASE STUDY | Zigs and zags of the smallpox virus
Smallpox, a once highly lethal contagious disease, has been eradicated worldwide. However, research continues with stored samples of variola, the smallpox virus, because it is a potential weapon in bioterrorism. Human cells protect themselves from the variola virus (and other viruses) by activating genes that encode protective proteins. It has recently been discovered that in response to variola, human cells create small transitory stretches of Z-DNA at sites that regulate these genes. The smallpox virus can bypass this cellular defense mechanism by specifically targeting the segments of Z-DNA and inhibiting the synthesis of the protective proteins. This discovery raises some interesting questions:
How might the virus target host-cell Z-DNA formation to block the synthesis of antiviral proteins?
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Essentials of Genetics - Masteringgenetic
- 1. Below is the base sequence of protein for normal hemoglobin and the base sequence for the sickle cell hemoglobin:Normal: GGG CTT CTT TTTSickle: GGG CAT CTT TTTa. Transcribe and translate the normal and sickle cell DNA. b. Identify this as a point or frameshift mutation. Explain. c. If the base sequence read GGG CTT CTT AAA instead, would this result in sickle cell hemoglobin? Explain.arrow_forwardDiscuss Concepts The genome of the yeast Saccharomyces cerevisiae is only about 0.4% the size of the human genome, yet itcontains about 30% as many genes as are in the human genome. Given that, which of the features of the human genome would you expect to find many fewer of in the yeast genome?arrow_forwardBt toxin is considered to be. a gene for modifying insect DNA an organic insecticide produced by bacteria useful for humans to fight against insects a recombinant proteinarrow_forward
- Discuss Concepts A forensic scientist obtained a small DNA sample from a crime scene. In order to examine the sample, he increased its quantity by cycling the sample through the polymerase chain reaction. He estimated that there were 50,000 copies of the DNA in his original sample. Derive a simple formula and calculate the number of copies he will have after15 cycles of the PCR.arrow_forwardGenetically Modified Foods The creation of transgenic crop plants using recombinant DNA methods involves the transfer of just one gene or a small number of genes to the plants, in contrast to classical breeding methods in which hundreds or even thousands of genes are transferred at once. Explain why this is true. If fewer genes are transferred during the creation of transgenic crops, why are some people afraid that they are dangerous?arrow_forward1. Given that a faulty ribosomal protein is the culprit and causes DBA, discuss the possible role of normal ribosomal proteins. Why might bone marrow cells be more susceptible to such a mutation than other cells? 2. A couple with a child affected with DBA undergoes in vitro fertilization (IVF) and genetic testing of the resulting embryos to ensure that the embryos will not have DBA. However, they also want the embryos screened to ensure that the one implanted can serve as a suitable donor for their existing child. Their plan is to have stem cells from the umbilical cord of the new baby transplanted to their existing child with DBA, thereby curing the condition. What are the ethical pros and cons of this situation? 3. While a stem cell transplant from an unaffected donor is currently the only cure for DBA, genome-editing technologies may one day enable the correction of a mutation in a patient’s own bone marrow stem cells. However, what specific information would be needed, beyond a…arrow_forward
- 3. Now that the sequence of the entire E. coli K12 straingenome (roughly 5 Mb) is known, you can determineexactly where a cloned fragment of DNA came fromin the genome by sequencing a few bases and matching that data with genomic information.a. About how many nucleotides of sequence information would you need to determine exactly where afragment is from?b. If you had purified a protein from E. coli cells,roughly how many amino acids of that proteinwould you need to know to establish which geneencoded the protein?c. You determine 100 nucleotides of sequence ofgenomic DNA from a different E. coli strain, butyou cannot find a match in the E. coli K12 genomesequence. How is this possible?arrow_forward52. Papaya plants are very susceptible to the papaya ringspot virus (PRSV), which stunts the growth of the fruit and negatively impacts the taste. By 1995, PRSV wiped out the Hawaiian papaya crop completely and made it impossible to produce papaya commercially. In 1998, Cornell University developed a genetically modified papaya called Rainbow that was resistant to PRSV and introduced it to Hawaii. Currently, 80% of the papaya cultivated in Hawaii is genetically modified to be resistant to PRSV.Which of the following rows identifies the effect of PRSV on the original papaya population and the reason why the population recovered? Select one: a. Effect on the Original Population Reason for Recovery Population bottleneck Some papaya had the PRSV-resistance gene. b. Effect on the Original Population Reason for Recovery Increased gene flow The PRSV-resistance gene had to be artificially introduced to the papaya genome c. Effect on the Original Population Reason…arrow_forward1. In what direction does a polymerase move when synthesizing a strand of mRNA? Briefly Explain. 2. Instead of the term “Formation of a nucleoside”, what could the name of the reaction be? What functional group is being formed? Briefly Explain.arrow_forward
- 1). In the absence of this enzyme, a substance called ceroid lipofuscin accumulates in lysosomes in the brain, resulting in seizures, blindness, decline in cognitive function and motor skills, dementia, and death by the late teens or early 20’s. The TPP1 gene is 6695 bp in length. Think about the characteristics of Batten disease, and then suggest an approach to gene therapy that might be effective for this specific genetic disorder. You may assume that your research team is working in the U.S. and your research is funded by a grant from the National Institutes of Health (NIH). a) Hypothetically, what specific type of VECTOR will you use to perform your gene therapy? Please select from the following list of potential vectors: disabled retrovirus, adenovirus, adeno-associated virus (AAV), or herpes simplex virus (HSV), then give two reasons why this specific vector is the most appropriate for your gene therapy. Please explain why you were able to rule out the other potential…arrow_forward1). In the absence of this enzyme, a substance called ceroid lipofuscin accumulates in lysosomes in the brain, resulting in seizures, blindness, decline in cognitive function and motor skills, dementia, and death by the late teens or early 20’s. The TPP1 gene is 6695 bp in length. Think about the characteristics of Batten disease, and then suggest an approach to gene therapy that might be effective for this specific genetic disorder. You may assume that your research team is working in the U.S. and your research is funded by a grant from the National Institutes of Health (NIH). Other scientists have suggested that it might be possible to use CRISPR to treat this genetic disorder in affected individuals. (i) First, what is CRISPR? (BRIEFLY describe what it is and how it works). (ii) Briefly describe how CRISPR could be utilized in treating genetic conditions such as Batten disease.arrow_forward1). In the absence of this enzyme, a substance called ceroid lipofuscin accumulates in lysosomes in the brain, resulting in seizures, blindness, decline in cognitive function and motor skills, dementia, and death by the late teens or early 20’s. The TPP1 gene is 6695 bp in length. Think about the characteristics of Batten disease, and then suggest an approach to gene therapy that might be effective for this specific genetic disorder. You may assume that your research team is working in the U.S. and your research is funded by a grant from the National Institutes of Health (NIH). Please EXCLUDE the use of CRISPR from consideration. A. Will you use germline or somatic cell gene therapy? Please NAME and DEFINE the form of gene therapy selected, then explain WHY this is the most appropriate choice.arrow_forward
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