Nokea
Vacuoles are large sacs for storage in plant cells. What is their main function in animal cells?
- A. Protein synthesis
- B. Waste storage and disposal
- C. Photosynthesis
- D. Cellular respiration
Correct Answer: B
Rationale: Vacuoles in animal cells primarily function in waste storage and disposal, helping to maintain cellular homeostasis by storing waste products and aiding in their removal from the cell. Unlike plant cells, animal cells do not typically use vacuoles for storage purposes such as water, nutrients, or pigments. Instead, animal cells rely on other organelles like lysosomes for waste management and maintaining cellular balance. Choices A, C, and D are incorrect because protein synthesis occurs in ribosomes, photosynthesis takes place in chloroplasts (absent in animal cells), and cellular respiration mainly occurs in mitochondria, respectively. Vacuoles in animal cells serve a different purpose compared to plant cells.
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Which vitamin is essential for calcium absorption and bone health?
- A. Vitamin A
- B. Vitamin C
- C. Vitamin D
- D. Vitamin E
Correct Answer: C
Rationale: Vitamin D is essential for calcium absorption in the intestines, which is crucial for maintaining strong and healthy bones. Without adequate vitamin D, the body cannot effectively absorb calcium, leading to weakened bones and an increased risk of fractures. Vitamin A (Choice A) is important for vision and immune function but is not directly involved in calcium absorption or bone health. Vitamin C (Choice B) is essential for collagen synthesis and immune function, but it does not play a direct role in calcium absorption or bone health. Vitamin E (Choice D) acts as an antioxidant and helps protect cells from damage, but it is not specifically required for calcium absorption or bone health. Therefore, the correct answer is Vitamin D as it is crucial for optimal bone health.
Chyle, a milky white fluid, is transported by lymphatic vessels from the:
- A. Lungs
- B. Intestines
- C. Kidneys
- D. Skin
Correct Answer: B
Rationale: Chyle, a milky white fluid, is formed in the small intestine during digestion. It is composed of lymph and emulsified fats. Lymphatic vessels in the intestines, specifically lacteals, transport chyle from the intestines to the bloodstream for the distribution of nutrients throughout the body. The transport of chyle from the lungs, kidneys, or skin is not correct as these organs are not primarily involved in the production or transportation of chyle.
What type of force opposes the motion of an object moving through a fluid (liquid or gas)?
- A. Gravitational force
- B. Tension force
- C. Viscous force
- D. Magnetic force
Correct Answer: C
Rationale: When an object moves through a fluid, it experiences resistance due to the viscosity of the fluid. This resistance is known as the viscous force, which opposes the motion of the object. Gravitational force is the force of attraction between two objects with mass, tension force is the force transmitted through a string, and magnetic force is the force exerted by magnets. In the context of an object moving through a fluid, the force opposing its motion is the viscous force because it resists the relative motion of the object through the fluid.
What is the principle behind the phenomenon of refraction, where waves bend when entering a new medium?
- A. Change in wavelength
- B. Change in frequency
- C. Change in wave speed
- D. None of the above
Correct Answer: C
Rationale: Refraction occurs due to a change in wave speed when waves enter a new medium. As waves travel from one medium to another, their speed changes, causing them to bend. This change in speed is responsible for the bending of waves during refraction. It is not the change in wavelength or frequency that causes refraction, but rather the change in speed as waves move through different mediums. Therefore, the correct answer is the change in wave speed (Choice C). Choices A and B are incorrect as refraction is not primarily influenced by changes in wavelength or frequency, but by changes in wave speed. Choice D is also incorrect as there is a specific principle, which is the change in wave speed, behind the phenomenon of refraction.
What is the term for the process of exchanging gases (oxygen and carbon dioxide) between the blood and the tissues?
- A. Inhalation
- B. Exhalation
- C. External respiration
- D. Internal respiration
Correct Answer: C
Rationale: External respiration is the correct term for the process of exchanging gases (oxygen and carbon dioxide) between the blood and the tissues. It specifically refers to the exchange of gases that occurs in the lungs, where oxygen is absorbed into the bloodstream and carbon dioxide is released from the bloodstream to be exhaled. Inhalation and exhalation, choices A and B, are phases of the breathing process that involve the intake and expulsion of air into and out of the lungs, respectively. Internal respiration, choice D, is the process of gas exchange that happens at the cellular level between the blood and body tissues, not between the blood and the lungs or tissues as in external respiration. Therefore, external respiration is the most appropriate term for the described gas exchange process in the question.