Nokea
Which hormone is responsible for regulating sleep-wake cycles and is influenced by light exposure?
- A. Melatonin
- B. Cortisol
- C. Estrogen
- D. Glucagon
Correct Answer: A
Rationale: The correct answer is A: Melatonin. Melatonin is the hormone responsible for regulating sleep-wake cycles, also known as the circadian rhythm. Its production is influenced by light exposure, with levels increasing in the evening in response to darkness, signaling the body that it is time to sleep. Choice B, cortisol, is a stress hormone and does not directly regulate sleep-wake cycles. Choice C, estrogen, is a sex hormone and is not primarily involved in regulating sleep. Choice D, glucagon, is a hormone that increases blood glucose levels and is not related to sleep-wake cycles.
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During photosynthesis, plants capture sunlight and convert water and carbon dioxide into glucose and oxygen. This is an example of a:
- A. Decomposition reaction
- B. Combustion reaction
- C. Synthesis reaction
- D. Double displacement reaction
Correct Answer: C
Rationale: This is an example of a synthesis reaction because simpler substances (water and carbon dioxide) are combined to form a more complex substance (glucose) in the presence of sunlight. Choice A (Decomposition reaction) involves breaking down a compound into simpler substances, which is the opposite of what happens in photosynthesis. Choice B (Combustion reaction) typically involves a substance reacting with oxygen to produce heat and light, not the formation of glucose and oxygen from simpler substances. Choice D (Double displacement reaction) involves an exchange of ions between two compounds, which is not what occurs in photosynthesis.
What is the relationship between work, force, and displacement?
- A. Work is directly proportional to force but inversely proportional to displacement
- B. Work is directly proportional to both force and displacement
- C. Work is inversely proportional to force but directly proportional to displacement
- D. Work is inversely proportional to both force and displacement
Correct Answer: B
Rationale: Work is directly proportional to both force and displacement. The work done on an object is calculated by multiplying the force applied to the object by the distance the object moves in the direction of the force. Therefore, work is directly proportional to both force and displacement. Choice A is incorrect because work is not inversely proportional to displacement. Choice C is incorrect because work is not inversely proportional to force. Choice D is incorrect because work is not inversely proportional to both force and displacement.
Which type of cartilage allows for smooth movement at joints and absorbs shock?
- A. Hyaline cartilage
- B. Fibrocartilage
- C. Elastic cartilage
- D. None of the above
Correct Answer: B
Rationale: Fibrocartilage is the correct answer. It is found in areas requiring both support and resilience, such as the intervertebral discs and knee joints. Fibrocartilage contains collagen fibers for strength and proteoglycans for resilience, making it suitable for functions that involve smooth movement at joints and shock absorption. Hyaline cartilage, while providing structural support, is not primarily responsible for smooth movement and shock absorption. Elastic cartilage is more flexible and is found in locations like the ear and epiglottis, but it is not known for its shock-absorbing properties. Choosing 'None of the above' disregards the correct option of fibrocartilage, which is specifically designed for the functions described in the question.
Which hormone is responsible for the characteristic changes experienced during puberty, such as breast development and menstruation in females?
- A. Follicle-stimulating hormone (FSH)
- B. Luteinizing hormone (LH)
- C. Estrogen
- D. Progesterone
Correct Answer: C
Rationale: Estrogen is the hormone responsible for the characteristic changes experienced during puberty in females, such as breast development and menstruation. Estrogen plays a crucial role in the development of secondary sexual characteristics and the regulation of the menstrual cycle. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are primarily involved in the regulation of the menstrual cycle and ovulation. Progesterone, on the other hand, is important for preparing the uterus for pregnancy and maintaining pregnancy, but it is not the primary hormone responsible for the changes seen during puberty in females.
What is the most common cause of hospital-acquired infections (HAIs)?
- A. Viruses
- B. Bacteria
- C. Fungi
- D. Parasites
Correct Answer: B
Rationale: Hospital-acquired infections (HAIs), also known as nosocomial infections, are infections that patients acquire during the course of receiving treatment in a healthcare facility. Among the options provided, bacteria are the most common cause of HAIs. Bacteria such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa are known to cause a wide range of infections in healthcare settings. While viruses, fungi, and parasites can also cause HAIs, bacteria are the most prevalent and significant pathogens responsible for these infections. Proper infection control measures, including hand hygiene, environmental cleaning, and antimicrobial stewardship, are essential in preventing and controlling HAIs caused by bacteria.