What is the role of RNA in protein synthesis?

Correct Answer: B

Rationale: RNA plays a crucial role in protein synthesis by decoding the genetic information stored in DNA and carrying it to the ribosomes where proteins are synthesized. This process involves transcription, where RNA is synthesized from DNA, and translation, where the information in RNA is used to assemble amino acids into proteins. RNA acts as a messenger between DNA and the ribosomes, ensuring that the correct sequence of amino acids is used to build proteins according to the genetic code. Option A is incorrect because DNA, not RNA, stores genetic information. Option C is incorrect because RNA does not provide energy for protein synthesis; energy is usually provided by ATP molecules. Option D is incorrect because tRNA (transfer RNA) is responsible for transporting amino acids to the ribosomes, not RNA in general. Therefore, option B is the most appropriate choice as it accurately describes the role of RNA in protein synthesis.

Correct Answer: A

Rationale: RNA splicing is a crucial process in gene expression where non-coding regions called introns are removed from the pre-mRNA molecule, and the remaining coding regions called exons are joined together to form the mature mRNA molecule. This process ensures that only the protein-coding sequences are retained in the mRNA for translation, allowing for the production of functional proteins. Therefore, option A is the correct answer as it accurately describes the importance of RNA splicing in generating mature mRNA molecules for protein synthesis. B) Adding the poly-A tail to the mRNA molecule is a post-transcriptional modification that occurs after RNA splicing and is not directly related to the process of removing introns. C) Activating the mRNA molecule for translation is typically achieved through the addition of a 5' cap and the poly-A tail, rather than through RNA splicing. D) Modifying the structure of the protein is not directly related to the process of RNA splicing, which primarily focuses on mRNA maturation by removing non-coding introns.

Correct Answer: C

Rationale: Momentum in physics is the product of an object's mass and its velocity. It is a vector quantity that describes the motion of an object and is given by the formula p = mv, where p is momentum, m is mass, and v is velocity. Therefore, momentum is best described as the mass of an object in motion. Choice A, 'Force exerted on an object,' is incorrect because force is not equivalent to momentum. Choice B, 'Speed of an object in motion,' is incorrect because speed only considers the rate of motion and not the mass aspect. Choice D, 'Distance traveled per unit time,' is incorrect as it relates to speed and not momentum, which involves both mass and velocity.

Correct Answer: A

Rationale: The correct unit of measurement for momentum is Newton-second (N·s). Momentum is calculated as the product of an object's mass and its velocity. The unit of mass is kilograms (kg) and the unit of velocity is meters per second (m/s). Therefore, the unit of momentum is kilogram-meter per second (kg·m/s). By Newton's second law of motion (F = ma), force is measured in Newtons (N), which is equivalent to kg·m/s². Multiplying the unit of force (N) by the unit of time (s) gives the unit of momentum as Newton-second (N·s). Choice B, Kilogram-meter (kg·m), is incorrect because it represents the unit of work or energy, not momentum. Choice C, Joule (J), is incorrect as it is a unit of energy. Choice D, Meter per second (m/s), is incorrect as it represents velocity alone, not momentum which is a vector quantity involving mass and velocity.

Correct Answer: D

Rationale: The SI unit of measurement for acceleration is meters per second squared (m/s²). Acceleration is defined as the rate of change of velocity over time. It is a vector quantity with dimensions of length per time squared. Meters per second squared (m/s²) represents the change in velocity (meters per second) over a specific time interval (seconds) squared. Choice A, meters per second (m/s), represents velocity, not acceleration. Choice B, Newton (N), is the unit of force. Choice C, Meters (m), represents only distance, not acceleration. Therefore, the correct unit for acceleration is meters per second squared (m/s²).