Nokea
What is the role of transfer RNA (tRNA) in protein synthesis?
- A. Transcribes DNA into mRNA
- B. Decodes the genetic code on mRNA
- C. Carries specific amino acids to the ribosomes
- D. Modifies the structure of proteins
Correct Answer: C
Rationale: A) Transcribes DNA into mRNA: This is the function of RNA polymerase, not transfer RNA (tRNA). tRNA is involved in protein synthesis, not transcription. B) Decodes the genetic code on mRNA: This is the function of tRNA during translation. tRNA molecules carry specific amino acids and recognize the codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain. C) Carries specific amino acids to the ribosomes: This is the primary role of tRNA in protein synthesis. Each tRNA molecule is specific for a particular amino acid and carries it to the ribosome, where it is added to the growing protein chain. D) Modifies the structure of proteins: This is not a function of tRNA. Protein modification can occur after translation is complete and involves other cellular processes and molecules.
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What happens to the speed of a sound wave when it travels from air to water?
- A. It increases because water is denser.
- B. It decreases because water is denser.
- C. It remains the same.
- D. Speed depends on the frequency, not the medium.
Correct Answer: B
Rationale: When a sound wave travels from air to water, the speed of sound decreases because sound travels faster in denser mediums. Water, being denser than air, causes the speed of sound to slow down. Choice A is incorrect because sound travels faster in denser mediums, so the speed would not increase. Choice C is incorrect because the speed of sound changes when transitioning between different mediums. Choice D is incorrect because while frequency does affect sound, the medium it travels through also plays a significant role in determining the speed of sound.
What phenomenon explains the bending of light as it passes around an obstacle or through an aperture?
- A. Refraction
- B. Reflection
- C. Diffraction
- D. Dispersion
Correct Answer: C
Rationale: Diffraction is the phenomenon that explains the bending of light as it passes around an obstacle or through an aperture. When light encounters an obstacle or passes through an aperture, it diffracts, causing it to bend around the edges. Refraction, on the other hand, occurs when light passes from one medium to another, causing it to change direction. Reflection involves the bouncing back of light rays from a surface, and dispersion is the separation of light into its different colors. Therefore, the correct answer is C, as diffraction specifically addresses the bending of light as it interacts with obstacles or apertures, unlike the other choices that describe different optical phenomena.
What does the phrase 'survival of the fittest' refer to?
- A. Organisms with the most complex anatomical structures are more likely to survive and reproduce.
- B. Organisms that demonstrate the best adaptations to their environment have a higher chance of survival and reproduction.
- C. All organisms have an equal probability of survival and reproductive success regardless of their traits.
- D. Only the strongest and most aggressive individuals within a population will survive and reproduce.
Correct Answer: B
Rationale: The phrase 'survival of the fittest' is often associated with the concept of natural selection, proposed by Charles Darwin. Natural selection is the process by which organisms best adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation. This process does not necessarily favor the most complex anatomical structures (option A) or the strongest and most aggressive individuals (option D). Instead, it emphasizes the importance of adaptations that enhance an organism's ability to survive and reproduce in a specific environment. Option C is incorrect because natural selection results in differential reproductive success based on an organism's traits, meaning that not all organisms have an equal probability of survival and reproductive success.
What are apocrine and eccrine?
- A. Blood vessel
- B. Cell types
- C. Hormones
- D. Sweat glands
Correct Answer: D
Rationale: Apocrine and eccrine refer to types of sweat glands in the human body. Apocrine sweat glands are larger and located in areas like the armpits and groin, producing a thicker secretion that can be associated with body odor. Eccrine sweat glands are found throughout the skin and are responsible for regulating body temperature through the production of sweat. Understanding the functions and locations of these glands is essential in comprehending the body's thermoregulation processes.
Dysentery is an infectious disease caused by which type of microbe?
- A. Helminth
- B. Bacteria
- C. Protozoan
- D. Fungus
Correct Answer: B
Rationale: The correct answer is B: Bacteria. Dysentery is typically caused by bacterial infections, such as Shigella, Campylobacter, or Escherichia coli. While parasites and protozoa can also cause similar symptoms, bacterial infections are the most common causes of dysentery. Choice A (Helminth) is incorrect as helminths are parasitic worms that typically cause different types of infections. Choice C (Protozoan) is incorrect as some protozoa like Entamoeba histolytica can cause dysentery, but bacterial infections are more common. Choice D (Fungus) is incorrect as fungal infections do not typically cause dysentery.