Mr. Scott has been diagnosed with hemochromatosis. He reads the following information on medical websites. Hereditary hemochromatosis is a genetic disease that alters the body's ability to regulate iron absorption. Common symptoms include tiredness, joint pain, abdominal pain, skin darkening, hair loss, and weakness.
Hereditary hemochromatosis is usually caused by a common gene mutation known as C282Y. But other mutations that cause this disease have also been Identified, including one known as H63D.
A child who inherits two copies of a mutated gene (one from each parent) is highly likely to develop the disease. However, not all people who have two mutated copies develop signs and symptoms of hereditary hemochromatosis.
People who inherit only one copy of the mutated gene are carriers, but usually have no symptoms, or have very mild symptoms since one correct copy of the gene appears to adequately regulate iron absorption.
Which statement correctly summarizes this information?
- A. Hemochromatosis is a dominant genetic disease caused by a single mutation.
- B. Hemochromatosis is a recessive genetic disease, but is caused by a lack of iron.
- C. Hemochromatosis is a recessive genetic disease, but the expression differs in individuals.
- D. Hemochromatosis is a dominant genetic disease that can be caused by several different alleles.
Correct Answer & Rationale
Correct Answer: C
Hemochromatosis is indeed a recessive genetic disorder, meaning that two copies of the mutated gene are typically required for the disease to manifest. Option A incorrectly categorizes it as a dominant disease, which does not align with its genetic inheritance pattern. Option B misstates the condition, as hemochromatosis is characterized by iron overload, not a deficiency. Option D also misrepresents the disease; while there are different alleles involved, hemochromatosis is primarily recessive, not dominant, making option C the most accurate summary of the information.
Hemochromatosis is indeed a recessive genetic disorder, meaning that two copies of the mutated gene are typically required for the disease to manifest. Option A incorrectly categorizes it as a dominant disease, which does not align with its genetic inheritance pattern. Option B misstates the condition, as hemochromatosis is characterized by iron overload, not a deficiency. Option D also misrepresents the disease; while there are different alleles involved, hemochromatosis is primarily recessive, not dominant, making option C the most accurate summary of the information.
Other Related Questions
Which instruction would be most appropriate for step 2 of the procedure?
- A. Provide both group A and group B participants with a daily magnesium supplement.
- B. Provide group A participants with a daily magnesium supplement and provide group B participants with a daily supplement that contains only inactive ingredients.
- C. Provide group A participants with a high-magnesium supplement and group B participants with a low-magnesium supplement...
- D. Provide both group A and group B participants with guidelines about which foods they should consume.
Correct Answer & Rationale
Correct Answer: B
Option B is the most appropriate instruction for step 2 as it establishes a clear experimental control. By giving group A a magnesium supplement and group B an inactive placebo, it allows for a direct comparison of the effects of magnesium on the participants. Option A is incorrect because it does not create a control group; both groups would receive magnesium, making it impossible to determine its specific effects. Option C is flawed as it introduces an additional variable by varying the magnesium levels between groups, complicating the results. Option D fails to provide a direct intervention, which is essential for assessing the impact of magnesium supplementation.
Option B is the most appropriate instruction for step 2 as it establishes a clear experimental control. By giving group A a magnesium supplement and group B an inactive placebo, it allows for a direct comparison of the effects of magnesium on the participants. Option A is incorrect because it does not create a control group; both groups would receive magnesium, making it impossible to determine its specific effects. Option C is flawed as it introduces an additional variable by varying the magnesium levels between groups, complicating the results. Option D fails to provide a direct intervention, which is essential for assessing the impact of magnesium supplementation.
which sentence describes a difference between artificial selection and natural selection?
- A. In natural selection, variation is heritable; in artificial selection, variation is not heritable.
- B. In natural selection, there is differential reproduction; in artificial selection, there is not differential reproduction.
- C. In natural selection, there is variation within the population of organisms; in artificial selection, there is no variation within the population or organisms.
- D. In natural selection, reproductive success is driven by naturally occurring processes; in artificial selection, reproductive success is driven by human-imposed processes.
Correct Answer & Rationale
Correct Answer: D
Natural selection occurs through naturally occurring processes where organisms with advantageous traits are more likely to survive and reproduce, leading to evolutionary change over time. In contrast, artificial selection involves human intervention, where specific traits are chosen for breeding based on human preferences. Option A is incorrect; both types of selection involve heritable variation. Option B misrepresents artificial selection, which also involves differential reproduction based on selected traits. Option C is inaccurate as artificial selection can still involve variation within the chosen traits. Thus, option D accurately highlights the fundamental distinction between the two processes.
Natural selection occurs through naturally occurring processes where organisms with advantageous traits are more likely to survive and reproduce, leading to evolutionary change over time. In contrast, artificial selection involves human intervention, where specific traits are chosen for breeding based on human preferences. Option A is incorrect; both types of selection involve heritable variation. Option B misrepresents artificial selection, which also involves differential reproduction based on selected traits. Option C is inaccurate as artificial selection can still involve variation within the chosen traits. Thus, option D accurately highlights the fundamental distinction between the two processes.
Which statement explains the central idea of the passage?
- A. People should consume as much magnesium as possible to ensure good cardiovascular health.
- B. People may experience health benefits from drinking hard water because it contains magnesium.
- C. People who live in rural environments are healthier than people who live in urban environments.
- D. People should stop the practice of softening water because it removes minerals that are necessary for good health.
Correct Answer & Rationale
Correct Answer: B
Option B accurately reflects the central idea by highlighting the potential health benefits of magnesium found in hard water. This aligns with the passage's focus on the relationship between magnesium intake and cardiovascular health. Option A is misleading as it suggests an excessive intake of magnesium is necessary, while the passage likely emphasizes balance rather than maximum consumption. Option C incorrectly generalizes health comparisons between rural and urban populations without specific evidence from the passage. Option D misrepresents the passage's message by implying a complete cessation of water softening, rather than discussing the importance of maintaining essential minerals like magnesium.
Option B accurately reflects the central idea by highlighting the potential health benefits of magnesium found in hard water. This aligns with the passage's focus on the relationship between magnesium intake and cardiovascular health. Option A is misleading as it suggests an excessive intake of magnesium is necessary, while the passage likely emphasizes balance rather than maximum consumption. Option C incorrectly generalizes health comparisons between rural and urban populations without specific evidence from the passage. Option D misrepresents the passage's message by implying a complete cessation of water softening, rather than discussing the importance of maintaining essential minerals like magnesium.
Which statement from the passage refutes Lavoisier's idea that heat is a fluid that leaves a hot substance and travels to a colder substance?
- A. He also found the brass filings produced from the drilling process contained enough heat to boil water while retaining their weight.
- B. James Joule discovered that heat could be produced by moving a wire through a magnetic field.
- C. Lavoisier demonstrated that oxygen was required for combustion.
- D. Count Rumford observed that the process of boring out cannons from brass cylinders continuously produced heat.
Correct Answer & Rationale
Correct Answer: A
Option A effectively refutes Lavoisier's notion of heat as a fluid by demonstrating that heat can be generated without the transfer of a fluid. The brass filings, despite retaining their weight, produced sufficient heat to boil water, indicating that heat can arise from mechanical processes rather than fluid movement. Option B, while highlighting Joule's discovery of heat production through motion, does not directly address Lavoisier's fluid concept. Option C focuses on combustion and oxygen's role, which is unrelated to the nature of heat itself. Option D describes an observation of heat generation during a mechanical process but does not emphasize the implications for Lavoisier's fluid theory as clearly as A does.
Option A effectively refutes Lavoisier's notion of heat as a fluid by demonstrating that heat can be generated without the transfer of a fluid. The brass filings, despite retaining their weight, produced sufficient heat to boil water, indicating that heat can arise from mechanical processes rather than fluid movement. Option B, while highlighting Joule's discovery of heat production through motion, does not directly address Lavoisier's fluid concept. Option C focuses on combustion and oxygen's role, which is unrelated to the nature of heat itself. Option D describes an observation of heat generation during a mechanical process but does not emphasize the implications for Lavoisier's fluid theory as clearly as A does.