1. A genetic counselor is consulted by a young man who is worried about developing Huntington’s disease, an inherited disorder caused by a dominant allele of a single gene. The young man explains that his cousin was recently diagnosed with Huntington’s disease, and the news has caused him to consider his own risk of developing the disorder. Which of the following questions will best help the genetic counselor to evaluate the risk of the young man developing Huntington’s disease and transmitting it to his children?
(A) Were you and your cousin born in the same geographical area?
(B) Were your parents or grandparents ever diagnosed with Huntington’s disease?
(C) Were you in physical contact with a person diagnosed with Huntington’s disease?
(D) Were you ever exposed to substances that are suspected of being mutagens?
2. Over several years, bacteria were isolated from members of a human population and tested for antibiotic resistance. The percent of bacterial isolates that were found to be antibiotic resistant is presented in the graph above for each year of the study. Which of the following conclusions is best supported by the information presented in the graph?
(A) The greatest increase in antibiotic resistance occurred from the first year to the third year of the study.
(B) Gene flow in the population occurred at the same rate for the entire duration of the eight-year study.
(C) Because evolution in bacterial populations occurs over millions of years, the results are due to random variation.
(D) Natural selection over multiple generations is favoring antibiotic resistance in the population of bacteria.
3. Lobe-finned fishes were present in the oceans of the world approximately 400 million years ago. The first tetrapods (vertebrates that had limbs and could move on land) date to about 365 million years ago. One hypothesis states that early tetrapods evolved from lobe-finned fishes. Which of the following is the best plan for testing the hypothesis?
(A) Determining the number of fins found on lobe-finned fishes from different geographical locations
(B) Measuring the proportion of radioisotopes found in fossils of early tetrapods
(C) Comparing the arrangements of bones in the fins of lobe-finned fishes and limbs of the earliest tetrapods
(D) Sequencing DNA isolated from fossils of lobe-finned fishes to determine the size of the genome
4. Which of the following describes a metabolic consequence of a shortage of oxygen in muscle cells?
(A) An increase in blood pH due to the accumulation of lactic acid
(B) No ATP production due to the absence of substrate-level phosphorylation
(C) A buildup of lactic acid in the muscle tissue due to fermentation
(D) A decrease in the oxidation of fatty acids due to a shortage of ATP
5. Prairie dogs are small mammals that live in large colonies in burrows in the ground. Prairie dogs that are near their own relatives when a predator approaches are much more likely to issue a warning bark than those that are near unrelated prairie dogs. The prairie dogs that hear a warning bark are more likely to hide in their burrows than to remain above ground. However, the prairie dog that gives the warning bark is putting itself at increased risk of being identified and killed by the predator. Which of the following presents the most likely evolutionary explanation for the behaviors described?
(A) The warning bark changes the behavior of the related prairie dogs nearby, allowing the prairie dog’s family to have increased survival and reproductive success.
(B) The barking prairie dog chooses to warn other prairie dogs, leading to more prairie dogs living above ground.
(C) The barking prairie dog is alerting unrelated prairie dogs to the predator, so it is not giving any advantage to its own relatives.
(D) The failure of the individual to bark when surrounded by unrelated prairie dogs ensures survival of the individual.
6. One model of a sustainable fisheries practice is for individual fish to be removed from a natural population at a rate equal to the highest possible growth rate of an ideal population. The graph above represents a population of bluefin tuna living along the Atlantic coast. At which labeled point in the graph is the population growth rate the highest?
(A) I (B) II (C) III (D) IV
1. To determine the likelihood that a patient with a bacterial infection who is in the intensive care unit (ICU) of a hospital could be successfully treated with antibiotic therapies, researchers investigated the frequency of antibiotic resistance in bacteria isolated from patients in ICUs in the United States from 1994 to 2000. The data from the study are shown in the table, along with the overall change in the frequency of bacterial resistance in patient samples from 1994 to 2000.
(a) A patient was admitted to the ICU in December 2000 with an uncharacterized bacterial infection. Based on the data from the study, identify the following.
(b) Using the data, provide justification for the claim that antibiotic resistance may arise in bacterial species.
(c) Describe THREE different processes by which antibiotic resistance develops in individual bacterial cells.
(d) Describe TWO features of natural selection that lead to the spread of antibiotic resistance in a population over many generations. Give ONE reason that the development of antibiotic resistance is an example of evolution.
(e) Giving low doses of antibiotics to beef cattle to control the population sizes of intestinal bacteria can result in more efficient uptake of food materials by the cattle. Pose an ethical question that the Food and Drug Administration (FDA) should consider when deciding whether to approve this type of antibiotic use in beef cattle.
2. Human cells divide every day for normal growth, replacement of cells, and tissue repair. The dividing cells proceed through the three phases of the cell cycle as shown in the figure. When a person experiences a cut, damaged skin cells secrete a protein called epidermal growth factor (EGF). Epidermal (skin) cells in the vicinity of the injury possess proteins in their cell membranes called epidermal growth factor receptors (EGFR)
(a) Identify the THREE major stages of interphase, and describe the sequence in which they occur.
(b) Describe the most likely role of EGF and the role of EGFR in a cell signaling pathway. Describe how the cellular response to EGF results in tissue repair.
(c) Cancer can result from disruptions in cell cycle control. Mutations that increase the production of EGFR have been associated with skin cancer of the head and neck. Describe how a mutation outside of the coding region of a gene that encodes EGFR could lead to the overproduction of EGFR protein in a skin cell.
(d) In cases of skin cancer that are associated with overproduction of EGFR, treatment with antibodies against the extracellular portion of EGFR has been successful. Propose a model to explain how the antibody therapy most likely interferes with the cell signaling pathway, and give ONE reason the therapy is effective for treating cancer.