How are DNA and protein structures similar?

Correct Answer: A

Rationale: The correct answer is A because both DNA and proteins are polymers composed of repeating units. In DNA, the subunits are nucleotides, while in proteins, the subunits are amino acids. This structural similarity allows for the interchangeability of subunits during synthesis and provides diversity in molecular structures and functions. Choice B is incorrect because while hydrogen bonds are important in stabilizing the structures of both DNA and proteins, they are not the primary determinant of their overall structure. Choice C is incorrect because while the shape of proteins (tertiary structure) directly influences their function, DNA function is primarily related to its sequence rather than its shape.

Correct Answer: D

Rationale: The correct answer is D because the Hardy-Weinberg equation requires all the conditions mentioned in choices A, B, and C to be met for a population to be in genetic equilibrium. Choice A ensures genetic diversity, choice B ensures no natural selection, and choice C ensures no gene flow from other populations, which are all essential for the equation to be valid. Therefore, the correct answer is D as it encompasses all necessary conditions.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Chromosome aberrations can arise through breakage, which may occur due to various factors such as errors during DNA replication or exposure to mutagens. Recombination can also lead to chromosome aberrations when there are errors in the exchange of genetic material between chromosomes. Additionally, radiation can cause chromosome aberrations by inducing DNA damage. Therefore, all the choices (A, B, and C) are valid mechanisms through which chromosome aberrations can arise.

Correct Answer: C

Rationale: The correct answer is C: It is a non-invasive technique. Ultrasound is safe and non-invasive, making it ideal for prenatal screening as it does not pose any risk to the mother or the fetus. Choices A and B are incorrect because ultrasound must be performed by a trained healthcare professional in a medical setting, not at home, and it requires specialized equipment and expertise, making it more expensive and reliant on advanced technology. Choice D is incorrect as choices A and B are not true, making it not all of the above.

Correct Answer: B

Rationale: The correct answer is B because noninvasive tests can provide accurate results without the need for invasive follow-up procedures like amniocentesis, reducing risks to the mother and fetus. Choice A is incorrect as noninvasive tests do not approach 100% detection for Down syndrome. Choice C is incorrect because noninvasive tests are typically done earlier in the pregnancy for better accuracy. Choice D is incorrect as noninvasive tests do not induce miscarriage, regardless of the baby's health status.