Nokea
Complete the following sentence: Lipid-soluble hormones are…
- A. Constantly produced within the anterior pituitary gland and released into the blood stream
- B. Hydrophilic and are transported in an un-conjugated form in the blood
- C. Interact with intracellular receptors and evoke changes in gene expression
- D. Formed from amino acids
Correct Answer: C
Rationale: The correct answer is C because lipid-soluble hormones can freely diffuse through cell membranes to interact with intracellular receptors, leading to changes in gene expression. This mechanism is characteristic of lipid-soluble hormones, such as steroid hormones. Choice A is incorrect because lipid-soluble hormones are not constantly produced in the anterior pituitary gland. Choice B is incorrect as lipid-soluble hormones are hydrophobic, not hydrophilic, and are often transported bound to carrier proteins in the blood. Choice D is incorrect because lipid-soluble hormones are not formed from amino acids; rather, they are derived from cholesterol or similar compounds.
You may also like to solve these questions
The production and release of hormones caused by a chemical such as calcium is a _____ mechanism.
- A. humoral
- B. neural
- C. sensory
- D. hormonal
Correct Answer: A
Rationale: The correct answer is A: humoral. Humoral regulation refers to the control of physiological processes by substances in the blood, such as hormones. In this case, the production and release of hormones in response to a chemical like calcium is an example of humoral mechanism. This choice is correct because it specifically involves the blood-borne substances affecting hormone production.
Choices B, C, and D are incorrect because neural regulation (B) involves the nervous system controlling physiological processes, sensory regulation (C) refers to sensory input influencing responses, and hormonal regulation (D) involves feedback loops within the endocrine system, not directly related to blood-borne substances like calcium.
Which conditions would give the results shown in diagrams X and Y?
- A. carbon dioxide, 25°C, oxygen, 25°C
- B. carbon dioxide, 2°C, oxygen, 2°C
- C. oxygen, 25°C, carbon dioxide, 25°C
- D. oxygen, 2°C, carbon dioxide, 2°C
Correct Answer: C
Rationale: The correct answer is C because diagram X shows an increase in oxygen concentration over time, which indicates photosynthesis occurring. In photosynthesis, plants take in carbon dioxide and release oxygen. Therefore, the conditions of oxygen at 25°C and carbon dioxide at 25°C would support this process. Choices A, B, and D have incorrect combinations of temperature and gases that would not result in the observed increase in oxygen concentration in diagram X.
Narcolepsy is treated with:
- A. Amphetamine
- B. Adrenaline
- C. Isoprenaline
- D. Salbutamol
Correct Answer: A
Rationale: The correct answer is A: Amphetamine. Amphetamine is a central nervous system stimulant that helps manage narcolepsy symptoms by promoting wakefulness. It increases levels of neurotransmitters like dopamine and norepinephrine, enhancing alertness. Adrenaline (B), Isoprenaline (C), and Salbutamol (D) are not typically used to treat narcolepsy as they do not directly target the underlying cause of excessive daytime sleepiness. Adrenaline and Isoprenaline are more commonly used for acute situations like anaphylaxis or cardiac arrest. Salbutamol is a bronchodilator used for conditions like asthma.
Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________.
- A. ions
- B. deactivators
- C. nucleotides
- D. second messengers
Correct Answer: D
Rationale: The correct answer is D: second messengers. Protein or amino acid-based hormones are unable to pass through the cell membrane due to their large size and hydrophilic nature. Therefore, they bind to specific receptors on the cell surface, triggering a series of events that lead to the production of second messengers inside the cell. These second messengers, such as cyclic AMP or calcium ions, then transmit the hormonal signal to the target cell's interior to initiate a physiological response. Choices A, B, and C are incorrect because protein or amino acid-based hormones do not directly exert their effects through ions, deactivators, or nucleotides intracellularly.
Which of the following is true of both prolactin and oxytocin? Both
- A. are concerned with lactation.
- B. are secreted by the adenohypophysis.
- C. stimulate the mammary glands to make milk.
- D. are concerned only with lactation.
Correct Answer: A
Rationale: The correct answer is A: are concerned with lactation. Both prolactin and oxytocin are hormones involved in lactation. Prolactin promotes milk production in the mammary glands, while oxytocin stimulates the release of milk from the breasts during breastfeeding. Therefore, both hormones play crucial roles in the lactation process.
Choice B is incorrect because oxytocin is secreted by the posterior pituitary gland, not the adenohypophysis. Choice C is incorrect because oxytocin specifically stimulates the contraction of the muscles around the mammary glands to release milk, not the production of milk. Choice D is incorrect because oxytocin is also involved in milk ejection, not just lactation itself.