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. Diabetic nephropathy, a complication of diabetes, affects the:

A. Ureters
B. Bladder
C. Urethra
D. Nephrons

Correct answer: D

Rationale: Diabetic nephropathy, a complication of diabetes, affects the nephrons. Nephrons are the functional units of the kidneys responsible for filtering blood and producing urine. The high blood sugar levels associated with diabetes can damage the nephrons over time, leading to kidney dysfunction and, ultimately, kidney failure. Choices A, B, and C are incorrect because diabetic nephropathy primarily impacts the nephrons in the kidneys, not the ureters, bladder, or urethra.

3. Which element has the lowest electronegativity value?

A. Oxygen
B. Fluorine
C. Helium
D. Chlorine

Correct answer: C

Rationale: The correct answer is Helium (C). Electronegativity is the tendency of an atom to attract electrons towards itself in a bond. Helium, as a noble gas, has a very low electronegativity because its outer electron shell is already full and stable, resulting in minimal attraction for additional electrons. Oxygen (A), Fluorine (B), and Chlorine (D) are all non-noble gas elements that have higher electronegativity values compared to Helium due to their electron configurations and tendencies to attract electrons.

4. Which statement accurately describes the electron cloud model of the atom?

A. Electrons precisely orbit the nucleus in defined paths.
B. Electrons occupy specific energy levels around the nucleus with varying probabilities.
C. Electrons are clustered tightly within the nucleus.
D. Electrons move randomly throughout the entire atom.

Correct answer: B

Rationale: The electron cloud model of the atom describes electrons as occupying specific energy levels around the nucleus with varying probabilities. This model does not suggest that electrons precisely orbit in defined paths as stated in option A. It acknowledges the wave-like behavior of electrons and their uncertainty in position, which is not accounted for in options C and D. Option C is incorrect as electrons are not clustered tightly within the nucleus but exist in the space surrounding the nucleus. Option D is incorrect as electrons do not move randomly throughout the entire atom but have specific probabilities of being found in different regions based on their energy levels. Therefore, option B is the most accurate description of the electron cloud model of the atom.

5. In nuclear fusion, where does the released energy originate from?

A. The fission of heavy nuclei
B. The binding energy released during the fusion of light nuclei
C. Electronic transitions within atoms
D. Matter-antimatter annihilation

Correct answer: B

Rationale: The correct answer is B: 'The binding energy released during the fusion of light nuclei.' Nuclear fusion involves the combination of light nuclei to form a heavier nucleus, releasing energy in the process. This energy arises from the binding energy that keeps the nucleus intact. As lighter nuclei fuse, they create a more stable nucleus, and the excess energy is emitted as radiation. This fundamental process is the primary source of energy in stars and holds promise as a potential future energy source on Earth. Choices A, C, and D are incorrect. Choice A, 'The fission of heavy nuclei,' is related to nuclear fission, not fusion. Choice C, 'Electronic transitions within atoms,' refers to energy release in atomic transitions, not nuclear fusion. Choice D, 'Matter-antimatter annihilation,' is a process where matter and antimatter collide, converting their mass into energy, but it is not the energy source for nuclear fusion.