AP Bio Practice Exam 3: 100% Verified Questions & Answers : Latest Updated

Which of the following describes the most likely location of cholesterol in an animal cell? (Ans- Embedded in the plasma membrane Lactase is the enzyme needed to digest lactose; the sugar found in milk. Most mammals produce lactase when they are young but stop once nursing ends. In humans however, many people continue to produce lactase into adulthood and are referred to as lactase-persistent. Which of the following mutations is most likely to cause lactase persistence in humans? (Ans- A mutation that increases the binding of transcription factors to the promoter of the lactase gene Maturation promoting factor, MPFMPF, is a cyclin-CDKCDK complex that catalyzes the phosphorylation of other proteins to start mitosis. The activity level of MPFMPF is dependent on the relative concentrations of the cyclin and CDKCDK components of MPFMPF (Figure 1). Based on Figure 1, which of the following describes the role of cyclin in the regulation of the cell cycle? (Ans- During M phase, the cyclin level remains the same because DNA replication is occurring. Modern bananas originated from a cross between a tetraploid banana species and a diploid banana species. The product of this cross was the triploid Cavendish banana strain, a sterile hybrid that is only grown asexually. Recently, the Panama fungus has been observed more frequently parasitizing the Cavendish banana, and scientists claim that this type of banana is on the brink of extinction. Which of the following provides the best explanation of the scientists' claim regarding the threat to the Cavendish banana? (Ans- The lack of genetic diversity of the Cavendish banana decreases the chance that a variation exists in the population that is immune to the fungus. Belding's ground squirrels (Spermophilus beldingi) live in closely related groups. When they feed in the open, certain individuals (guard squirrels) watch for predators instead of feeding. The guard squirrels give an alarm call when a predator is sighted, allowing the rest of the group to run to safety. Researchers have noted that, because the alarm call draws attention to the guard, the guard is more likely to be caught by the predator and therefore has a lower survival rate in comparison with the other squirrels. Which of the following best explains the behavior of the guard squirrels? (Ans- The behavior of the guard squirrels increases the survival of close relatives that share the genes of the guard squirrels. If 30% of the nucleotides in a single-stranded RNA molecule are adenine, then what percent are expected to be thymine? (Ans- 0% Melanocytes are skin cells that can become cancerous and develop into a cancer known as melanoma. Some cancerous melanocytes have developed resistance to the drugs currently used to treat melanoma. As a result, researchers are investigating the effects of a new compound (drug XX) on four different melanoma cell lines. Researchers analyzed cell survival in two cell lines (Figure 1) and oxygen consumption in the presence of drug XX in all four cell lines (Figure 2). Figure 3 shows the proposed mechanism by which drug XX affects cells. Which of the following best describes the data in Figure 1 ? (Ans- At a concentration above 10 μM, drug X reduces melanoma cell survival. Melanocytes are skin cells that can become cancerous and develop into a cancer known as melanoma. Some cancerous melanocytes have developed resistance to the drugs currently used to treat melanoma. As a result, researchers are investigating the effects of a new compound (drug XX) on four different melanoma cell lines. Researchers analyzed cell survival in two cell lines (Figure 1) and oxygen consumption in the presence of drug XX in all four cell lines (Figure 2). Figure 3 shows the proposed mechanism by which drug XX affects cells