Nokea
Which statement is true about the pH of a solution?
- A. A solution cannot have a pH less than 0.
- B. A solution always has a pH of 7.
- C. A solution's pH is not influenced by its chemical composition.
- D. A solution with a pH of 14 is considered acidic.
Correct Answer: A
Rationale: The pH scale ranges from 0 to 14, with 0 being the most acidic, 7 neutral, and 14 the most basic. A solution with a pH less than 0 would be outside the defined pH range, as 0 is the lower limit. Therefore, a solution cannot have a pH less than 0. Choice B is incorrect because a pH of 7 is considered neutral, not always the pH of a solution. Choice C is incorrect because a solution's pH is influenced by its chemical composition. Choice D is incorrect as a solution with a pH of 14 is considered highly basic, not acidic.
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Which of the following systems does not include a transportation network throughout the body?
- A. Cardiovascular system
- B. Endocrine system
- C. Immune system
- D. Nervous system
Correct Answer: B
Rationale: The endocrine system does not include a transportation network throughout the body. While the cardiovascular system transports blood, oxygen, and nutrients, the immune system has lymphatic vessels for immune cell transportation, and the nervous system transmits signals via neurons. In contrast, the endocrine system coordinates bodily functions by releasing hormones directly into the bloodstream, which then act on target organs or tissues. This delivery mechanism is different from the continuous transportation networks found in the other systems listed, making the endocrine system the correct choice for this question.
Which three parts make up the large intestine?
- A. Duodenum, ileum, jejunum
- B. Cecum, colon, rectum
- C. Ileum, jejunum, rectum
- D. Colon, cecum, ileum
Correct Answer: B
Rationale: The correct answer is B: Cecum, colon, rectum. The large intestine is composed of the cecum, colon, and rectum. These parts are responsible for water absorption and feces formation. Choices A, C, and D are incorrect. A contains parts of the small intestine (duodenum, ileum, jejunum), C has a mix of small and large intestine parts, and D includes the small intestine part ileum. Understanding the correct anatomy of the large intestine is essential for distinguishing it from the small intestine.
Which of the following is directly transcribed from DNA and represents the first step in protein synthesis?
- A. siRNA
- B. rRNA
- C. mRNA
- D. tRNA
Correct Answer: C
Rationale: mRNA (messenger RNA) is directly transcribed from DNA in the nucleus during the process of transcription. It serves as a template for protein synthesis during translation in the cytoplasm. mRNA carries genetic information from the DNA to the ribosomes, where it determines the sequence of amino acids in a protein. Thus, mRNA represents the first step in protein synthesis as it carries the code from the DNA to be translated into a protein. Choice A, siRNA (small interfering RNA), is involved in post-transcriptional gene silencing and does not play a role in protein synthesis. Choice B, rRNA (ribosomal RNA), is a component of the ribosome and plays a structural and functional role in protein synthesis but is not directly transcribed from DNA. Choice D, tRNA (transfer RNA), is responsible for bringing amino acids to the ribosome during protein synthesis but is not directly transcribed from DNA.
Which type of reaction undergoes hydrolysis?
- A. Anabolism
- B. Catabolism
- C. Exothermic
- D. Endothermic
Correct Answer: B
Rationale: The correct answer is 'Catabolism.' Catabolic reactions involve the breakdown of larger molecules into smaller ones, often through hydrolysis, where water is added to break chemical bonds. This process is essential for the degradation of complex molecules and the release of energy stored in chemical bonds. Choice A, 'Anabolism,' is incorrect as anabolism involves the synthesis of complex molecules from simpler ones. Choices C and D, 'Exothermic' and 'Endothermic,' refer to the heat energy exchange during a reaction and are not directly related to the process of hydrolysis.
Which term refers to a position toward the feet? For example, the foot is part of the inferior extremity.
- A. Anterior
- B. Posterior
- C. Superior
- D. Inferior
Correct Answer: D
Rationale: The correct answer is 'Inferior.' 'Inferior' refers to a position located towards the feet or lower part of the body. This is the opposite of 'superior,' which indicates a position towards the head or upper part of the body. 'Anterior' refers to the front of the body, 'posterior' refers to the back of the body, making them incorrect choices in this context.