Nokea
Which of the following macromolecules will always contain nitrogen?
- A. Fatty acids
- B. Proteins
- C. Lipids
- D. Carbohydrates
Correct Answer: B
Rationale: The correct answer is B: Proteins. Proteins are the only macromolecules that always contain nitrogen in their amino acid structure. Nitrogen is a key element found in the amino groups of amino acids, which are the building blocks of proteins. Fatty acids (Choice A), lipids (Choice C), and carbohydrates (Choice D) do not always contain nitrogen in their structure. Fatty acids are composed of long hydrocarbon chains and do not contain nitrogen. Lipids consist mainly of carbon, hydrogen, and oxygen, with some classes of lipids containing phosphorus but not nitrogen. Carbohydrates are made up of carbon, hydrogen, and oxygen, forming structures like sugars and starches, but they do not contain nitrogen.
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Which of the following statements is not true about the relationship between the gastrointestinal system and the endocrine system?
- A. Hormones signal to your body whether you are hungry or full.
- B. Hormones regulate the amount of glucose in your blood.
- C. Hormones stimulate digestive enzymes and peristalsis when you've eaten and need to digest food.
- D. All of the above are true.
Correct Answer: D
Rationale: The gastrointestinal system and the endocrine system are closely interconnected. Hormones released by the endocrine system play a crucial role in signaling hunger or fullness, regulating blood glucose levels, and stimulating digestive processes like enzyme secretion and peristalsis for efficient food digestion. Option D, stating 'All of the above are true,' is incorrect in the context of the question because there is a need to identify the statement that is not true about the relationship between the gastrointestinal system and the endocrine system. Choices A, B, and C are all correct statements that reflect the close relationship and interactions between the gastrointestinal and endocrine systems.
What type of muscle is found in the walls of hollow organs like the intestines?
- A. Cardiac muscle
- B. Smooth muscle
- C. Skeletal muscle
- D. Voluntary muscle
Correct Answer: B
Rationale: Smooth muscle is the correct type of muscle found in the walls of hollow organs like the intestines. It is responsible for movements such as peristalsis, aiding in the movement of food and other materials through the digestive system. Cardiac muscle (Choice A) is found in the heart and is responsible for the heart's contractions, not in hollow organs like the intestines. Skeletal muscle (Choice C) is attached to bones and responsible for voluntary movements, not in hollow organ walls. Voluntary muscle (Choice D) is another term for skeletal muscle, which is under conscious control, unlike smooth muscle in hollow organ walls.
Which cellular organelle is used for digestion to recycle materials?
- A. The Golgi apparatus
- B. The lysosome
- C. The centrioles
- D. The mitochondria
Correct Answer: B
Rationale: The lysosome is the correct cellular organelle used for digestion to recycle materials. Lysosomes contain enzymes that break down waste materials, cellular debris, and ingested substances. This process helps in recycling nutrients and maintaining cellular homeostasis. The Golgi apparatus is involved in processing and packaging proteins, the centrioles play a role in cell division, and the mitochondria are responsible for energy production. However, none of these organelles are primarily used for digestion and recycling of materials within the cell.
What are the components of the female external genitalia and their functions?
- A. Ovaries: internal reproductive organs
- B. Vulva: external structures of the female genitalia
- C. Uterus: internal reproductive organ for fetal development
- D. Vagina: birth canal
Correct Answer: B
Rationale: The corrected answer is B: 'Vulva: external structures of the female genitalia.' The vulva includes external structures such as the labia, clitoris, and vaginal opening. These structures play roles in sexual arousal and protection of the internal genital organs. Choices A, C, and D are incorrect because they are internal reproductive organs. The ovaries produce eggs, the uterus houses the developing fetus, and the vagina serves as the birth canal. Hence, they are not components of the female external genitalia.
Which of the following is a chief difference between evaporation and boiling?
- A. Liquids boil only at the surface, while they evaporate equally throughout the liquid.
- B. Evaporating substances change from liquid to gas, while boiling substances change from gas to liquid.
- C. Evaporation can happen below a liquid's boiling point.
- D. Evaporation happens in nature, while boiling is a man-made phenomenon.
Correct Answer: C
Rationale: The chief difference between evaporation and boiling is that evaporation can happen below a liquid's boiling point, while boiling only occurs at the liquid's boiling point. Evaporation is the process of a liquid turning into a gas at any temperature, while boiling specifically refers to the rapid vaporization that occurs when a liquid reaches its boiling point. Choice A is incorrect because liquids evaporate throughout the liquid, not just at the surface. Choice B is incorrect as evaporating substances change from liquid to gas, while boiling substances change from liquid to gas. Choice C is incorrect as boiling is not a man-made phenomenon; in fact, it is a natural process based on temperature changes. Choice D is incorrect because evaporation can happen naturally and is not limited to man-made processes.