ati teas 7 science

Correct Answer: B

Rationale: In mitosis, sister chromatids are separated and move to opposite poles during Anaphase. This is when the spindle fibers shorten, pulling chromatids apart. Metaphase is when chromosomes align in the middle. Telophase is when the nuclear envelope reforms. Cytokinesis is the division of the cytoplasm. Therefore, B is correct as it specifically describes the phase where sister chromatids separate and move to opposite poles.

Correct Answer: B

Rationale: The correct answer is B: It runs 3' to 5'. The antisense strand of DNA runs in the opposite direction to the sense strand. This is essential for complementary base pairing during transcription. The 3' to 5' direction allows RNA polymerase to synthesize RNA in the 5' to 3' direction, following the template of the antisense strand. Therefore, choice B is correct. Choices A and C are incorrect because the directionality of the antisense strand is opposite to 5' to 3' and it is used in transcription, not replication. Choice D is incorrect as DNA is stored in the cell nucleus in a double helix structure, not in a specific direction.

Correct Answer: C

Rationale: The correct answer is C: Vitamin D. Vitamin D plays a crucial role in immune function by regulating the expression of genes involved in immune response. It helps in the production of antimicrobial peptides that defend against pathogens. Vitamin A is important for vision and skin health, not directly related to immune function. Vitamin B12 is essential for neurological function and red blood cell production. Vitamin E is an antioxidant that protects cells from damage but does not have a direct role in immune function. Therefore, the correct choice is Vitamin D as it directly supports immune system function.

Correct Answer: C

Rationale: The correct answer is C: Nephron. The nephron is the functional unit of the kidney responsible for filtering blood and reabsorbing essential substances like water, salts, and nutrients back into the body. It consists of various components like the glomerulus, proximal tubule, loop of Henle, and distal tubule, each playing a specific role in the reabsorption process. The renal artery brings blood to the kidney for filtration by the nephron, while the renal vein carries filtered blood away from the kidney. The glomerulus is a part of the nephron responsible for initial filtration of blood. Thus, the nephron is the correct structure for reabsorption, making choices A, B, and D incorrect.

Correct Answer: C

Rationale: The correct answer is C: Control sleep-wake cycles. Melatonin is primarily responsible for regulating our sleep-wake cycles, also known as the circadian rhythm. This hormone is released by the pineal gland in response to darkness, signaling to the body that it is time to sleep. Melatonin helps to synchronize our internal body clock with the natural day-night cycle. Choice A (Regulate blood pressure) is incorrect because melatonin does not play a direct role in regulating blood pressure. Choice B (Stimulate the digestive system) is incorrect as melatonin is not involved in stimulating the digestive system. Choice D (Maintain bone density) is also incorrect as melatonin's primary function is not related to bone density regulation.