Biology B: Exam 3 Questions and Answers Already Passed

Biology B: Exam 3 Questions and Answers Already Passed In pea plants, red flowers and round pollen are known to be recessive traits. In a dihybrid cross experiment, lots of plants with red flowers and round pollen are found in the F2 generation. How is this possible? The genes for flower color and pollen shape are linked. A Punnett square incorrectly predicts the outcome of a dihybrid cross. There are four phenotypes in the F2 offspring, but not in the expected ratios. Why? The genes are partially linked. If two genes show nearly 100 percent linkage, what does that tell us? Select all that apply. The two genes are always inherited together. The two genes are located very close to each other. The two genes are on the same chromosome. Which of the following are important uses of genetic maps? Select all that apply. locating genes that cause disease studying evolution Which type of enzyme repairs nicks or breaks along the DNA backbone? DNA ligase A biologist wishes to take a useful gene found in penguins and introduce it into some bacterial cells. Her experimental procedure is given below. 1. Use a restriction enzyme to cut a gene out of the penguin DNA. 2. Use a restriction enzyme to cut open a plasmid. 3. Treat the plasmid with DNA ligase. 4. Treat the plasmid with DNA polymerase. 5.Introduce the plasmid into bacterial cells. A step is missing. Where should it go in this procedure? "Mix the desired gene and plasmid together" should go between steps 2 and 3. Why are DNA primers an important ingredient in a PCR reaction? DNA polymerase cannot start to copy a DNA molecule without a double-stranded starting point. Primers create a double-stranded section of DNA. A lab technician is running a test on a patient's sample that is likely infected with salmonella. The technician correctly performs PCR on the sample using primers known to identify salmonella. Then they run the PCR product on an electrophoresis gel. What is the technician likely to see on the gel if the patient does have salmonella? bands matching the size found in known salmonella samples Which discovery came about as a result of the Human Genome Project? A large amount of DNA in our chromosomes does not code for any genes. "Whole genome sequencing increases the effectiveness of the treatment." Which sentences support this information? People can have personalized treatment plans. Physicians can diagnose diseases in early stages. What are some potential ethical problems with having the whole genome sequenced? It could be an obstacle in securing employment or medical insurance. It could be a source of worry, causing stress to individuals who are genetically predisposed to certain illnesses. What is the function of junk DNA in cells? Select all that apply. turning genes on and off protecting the ends of chromosomes How can gene cloning be used in medical science? to produce vaccines to produce useful proteins What is an ethical concern with cloning mammals? the low success rate of cloned embryos What is an ethical concern about editing genes for diseases in specific tissues like the lungs in humans? There may be unknown effects from altering the genome.