Nokea
What is hemoglobin?
- A. an enzyme
- B. a protein
- C. a lipid
- D. an acid
Correct Answer: B
Rationale: Hemoglobin is a protein found in red blood cells that plays a crucial role in transporting oxygen from the lungs to the tissues and organs in the body. It is composed of four protein subunits, each containing a heme group that binds to oxygen molecules. Choice A is incorrect as hemoglobin is not an enzyme, but rather a protein. Choice C is incorrect as hemoglobin is not a lipid, but a protein. Choice D is incorrect as hemoglobin is not an acid, but a protein.
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Examine the following decomposition reaction: ABC → ______. Which of the following is a possible set of products for this reaction?
- A. 2AB + C
- B. AB + CD
- C. A + BC
- D. B + C
Correct Answer: C
Rationale: In a decomposition reaction, a single reactant breaks down into two or more products. For the decomposition of ABC, a plausible set of products is A + BC. This reaction represents the breakdown of ABC into two separate components: A and BC. The correct choice C aligns with the fundamental concept of decomposition reactions, where a compound disintegrates into simpler substances. Choices A, B, and D do not reflect a proper decomposition reaction as they do not demonstrate the breakdown of the original compound into distinct components.
Which of the following is considered an extensive property?
- A. Weight
- B. Density
- C. Conductivity
- D. Malleability
Correct Answer: A
Rationale: Weight is correctly identified as an extensive property. Extensive properties are dependent on the amount of the substance present. Weight is directly proportional to the quantity of the substance, making it an extensive property. In contrast, density, conductivity, and malleability are intensive properties, which remain constant regardless of the amount of substance. Therefore, the correct answer is 'Weight' as it changes with the quantity of the substance, aligning with the definition of an extensive property.
Where is the scaphoid bone located in the body?
- A. Wrist
- B. Shoulder
- C. Spine
- D. Face
Correct Answer: A
Rationale: The correct answer is A: Wrist. The scaphoid bone is one of the carpal bones located in the wrist. It is a small boat-shaped bone that is frequently involved in wrist injuries, such as falls onto an outstretched hand resulting in a scaphoid fracture. Choices B, C, and D are incorrect as the scaphoid bone is not located in the shoulder, spine, or face. Understanding the anatomical location of bones is crucial for diagnosing and treating injuries accurately.
Which structure of the nervous system carries an action potential in the direction of a synapse?
- A. Cell body
- B. Axon
- C. Neuron
- D. Myelin
Correct Answer: B
Rationale: The correct answer is the axon. The axon is the elongated, threadlike part of a neuron that carries nerve impulses away from the cell body towards other neurons or target cells, such as muscles or glands, in the direction of a synapse. Action potentials travel along the axon as electrical signals to communicate with neighboring cells. The cell body (choice A) contains the nucleus and organelles but does not transmit action potentials. Neuron (choice C) is a broad term that includes the entire nerve cell, not a specific structure. Myelin (choice D) is a fatty substance that surrounds and insulates axons, aiding in the conduction of nerve impulses, but it does not directly carry the action potential towards a synapse.
How does meiosis differ from mitosis?
- A. Meiosis is used for repairing the body. Mitosis is used for cell reproduction.
- B. Meiosis is used for sexual reproduction. Mitosis is used for asexual reproduction.
- C. Meiosis occurs in various organisms. Mitosis occurs in various organisms.
- D. Meiosis produces cells that are genetically different. Mitosis produces cells that are genetically identical.
Correct Answer: D
Rationale: Meiosis is the process of cell division that results in the formation of sex cells (gametes) with only half the number of chromosomes as the parent cell, leading to genetically different cells. In contrast, mitosis is a cell division process that produces two daughter cells that are genetically identical to each other and the parent cell, maintaining the same chromosome number. Therefore, the correct answer is D, as meiosis and mitosis differ in their genetic outcomes - meiosis results in genetic diversity, while mitosis maintains genetic identity. Choices A, B, and C are incorrect because they do not accurately distinguish between meiosis and mitosis. Meiosis is not used for repairing the body or asexual reproduction, and the occurrence of both processes in various organisms does not highlight their primary differences in genetic outcomes.