what are the differences between rna and dna

ATI TEAS 7

TEAS 7 science practice

1. What are the differences between RNA and DNA?

A. Both have the same structure and function.
B. RNA is single-stranded, while DNA is double-stranded.
C. RNA contains ribose sugar, while DNA contains deoxyribose sugar.
D. RNA has adenine and guanine, while DNA has thymine and cytosine.

Correct answer: B

Rationale: A) This statement is incorrect. RNA and DNA have different structures and functions. RNA is involved in protein synthesis and other cellular processes, while DNA stores genetic information. B) This statement is correct. RNA is typically single-stranded, while DNA is double-stranded, forming a double helix structure. C) This statement is correct. RNA contains ribose sugar in its backbone, while DNA contains deoxyribose sugar. D) This statement is incorrect. RNA contains adenine, guanine, cytosine, and uracil, while DNA contains adenine, guanine, cytosine, and thymine. Choice B is the correct answer as it accurately describes one of the key differences between RNA and DNA, emphasizing their structural disparity in terms of single-strandedness for RNA and double-strandedness for DNA. Choices A, C, and D contain inaccuracies regarding the structural and compositional distinctions between RNA and DNA, making them incorrect choices.

2. In order to verify if a particular drug is responsible for the recovery of individuals with a disorder, what procedure would be most effective in testing its effectiveness?

A. Ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo.
B. Ensure that the subjects do not know whether they are given the drug or the placebo, but the investigators are aware of who has received the medication.
C. Ensure that the investigators do not know whether they are administering the drug or the placebo, but the subjects do know which they are receiving.
D. Ensure that both the investigators and the subjects have full knowledge of which subjects are getting the drug and which are getting a placebo.

Correct answer: A

Rationale: The most effective procedure in testing whether the drug is responsible for the recovery is to ensure that neither the subjects nor the investigators know which subjects are given the drug and which are given the placebo. This method is known as a double-blind study, which helps eliminate biases and ensures that the results are reliable and not influenced by expectations or beliefs. By keeping both the subjects and investigators unaware of who is receiving the drug or placebo, the study can accurately determine the true impact of the drug on recovery. Choice B is incorrect as it only prevents the subjects from knowing which treatment they are receiving, allowing for potential bias from the investigators. Choice C is also incorrect as it allows for potential bias from the subjects. Choice D is incorrect as full knowledge of treatment allocation can introduce bias and affect the study's validity.

3. During the process of oogenesis, primary oocytes produce:

A. sperm.
B. eggs.
C. oogonia.
D. stem cells.

Correct answer: B

Rationale: During the process of oogenesis, primary oocytes undergo meiosis to develop into secondary oocytes, which are the matured eggs released during ovulation for potential fertilization. Therefore, primary oocytes produce eggs, not sperm, oogonia, or stem cells, during oogenesis. Choice A (sperm) is incorrect as sperm is produced through spermatogenesis in males. Choice C (oogonia) is incorrect as oogonia are the cells that give rise to primary oocytes but are not the direct product of primary oocytes. Choice D (stem cells) is incorrect as primary oocytes do not directly produce stem cells during oogenesis.

4. Which part of the brain regulates body temperature, hunger, and thirst?

A. Cerebellum
B. Hypothalamus
C. Thalamus
D. Medulla oblongata

Correct answer: B

Rationale: The correct answer is the Hypothalamus. The hypothalamus is a crucial part of the brain that regulates various essential functions to maintain homeostasis. It controls body temperature, hunger, thirst, and plays a key role in the autonomic nervous system. The cerebellum is primarily involved in coordinating movement and balance, the thalamus acts as a relay station for sensory information, and the medulla oblongata is responsible for vital functions like breathing and heart rate. Therefore, choices A, C, and D are incorrect as they do not govern the specific functions mentioned in the question.

5. Which part of the brain is responsible for controlling involuntary functions like breathing and heart rate?

A. Cerebrum
B. Medulla oblongata
C. Cerebellum
D. Thalamus

Correct answer: B

Rationale: The medulla oblongata is located at the base of the brainstem and is responsible for controlling vital involuntary functions such as breathing, heart rate, and blood pressure. The cerebrum, although the largest part of the brain, is primarily responsible for higher brain functions like thinking and voluntary muscle movements. The cerebellum is involved in coordination, balance, and muscle control. The thalamus acts as a relay station for sensory information but is not directly responsible for regulating involuntary functions like breathing and heart rate. Therefore, the correct answer is the medulla oblongata.