Nokea
Which organelle in the cell contains the genetic material?
- A. Ribosome
- B. Nucleus
- C. Mitochondria
- D. Endoplasmic reticulum
Correct Answer: B
Rationale: The correct answer is B, Nucleus. The nucleus is the organelle in the cell that contains the genetic material (DNA). DNA within the nucleus determines the cell's functions and characteristics, making it essential for cell function and replication. Choice A, Ribosome, is responsible for protein synthesis, not genetic material storage. Choice C, Mitochondria, produces energy but does not contain the genetic material. Choice D, Endoplasmic reticulum, is involved in protein synthesis and lipid metabolism but does not house the genetic material.
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Which of the heart's four chambers is the largest and the strongest?
- A. Right atrium
- B. Left ventricle
- C. Right ventricle
- D. Left atrium
Correct Answer: B
Rationale: The left ventricle is the largest and strongest chamber of the heart. It pumps oxygenated blood to the body, making it vital for systemic circulation. The right atrium receives deoxygenated blood from the body, the right ventricle pumps this blood to the lungs, and the left atrium receives oxygenated blood from the lungs.
Which vitamin is essential for maintaining healthy skin and vision?
- A. Vitamin C
- B. Vitamin A
- C. Vitamin D
- D. Vitamin K
Correct Answer: B
Rationale: Vitamin A is the correct answer. It is essential for maintaining healthy skin and vision, especially in low-light conditions. Vitamin A helps in the production of retinal pigments necessary for vision in dim light and supports skin health by promoting cell turnover and repair.
Choice A, Vitamin C, is important for the immune system and collagen production but is not specifically known for maintaining skin and vision health.
Choice C, Vitamin D, is crucial for bone health and immune function but is not directly related to skin and vision health.
Choice D, Vitamin K, is necessary for blood clotting and bone health but does not play a significant role in maintaining healthy skin and vision.
Which of the following is not part of the central nervous system?
- A. Retina
- B. Spinal cord
- C. Brain
- D. Heart
Correct Answer: B
Rationale: The central nervous system consists of the brain and spinal cord, which are responsible for processing and coordinating information. The retina is part of the eye, while the heart is part of the circulatory system. Therefore, the correct answer is 'Spinal cord' as it is not part of the central nervous system.
Which cellular structure is responsible for producing energy?
- A. Nucleus
- B. Mitochondria
- C. Ribosome
- D. Golgi apparatus
Correct Answer: B
Rationale: Mitochondria are the organelles responsible for producing energy in the cell through a process called cellular respiration. They are often referred to as the powerhouses of the cell due to their role in generating ATP, the cell's energy currency. The nucleus is not involved in energy production but houses the cell's genetic material. Ribosomes are responsible for protein synthesis, not energy production. The Golgi apparatus is involved in processing and packaging proteins for secretion, not energy production.
Which hormone is involved in regulating the sleep-wake cycle?
- A. Insulin
- B. Melatonin
- C. Cortisol
- D. Thyroxine
Correct Answer: B
Rationale: The correct answer is B: Melatonin. Melatonin, produced by the pineal gland, is the hormone involved in regulating the sleep-wake cycle. It plays a crucial role in signaling the body that it is time to sleep and is influenced by light exposure. Melatonin levels typically rise in the evening, promoting sleep, and decrease in the morning, helping in waking up. Choice A, Insulin, is involved in regulating blood sugar levels, not the sleep-wake cycle. Choice C, Cortisol, is a stress hormone that helps regulate metabolism and immune response but is not primarily involved in the sleep-wake cycle. Choice D, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism, growth, and development, but it is not directly involved in regulating the sleep-wake cycle.