Which is NOT a characteristic or function of lipids?

Correct Answer: D

Rationale: Lipids are known for several functions including involvement in energy metabolism and storage (Choice A), providing insulation and protection (Choice B), and acting as hormones that regulate the body (Choice C). However, lipids are not hydrophilic (water-attracting), contrary to choice D. They are actually hydrophobic, meaning they repel water and do not mix well with it. This is a key property that differentiates them from many other biological molecules.

Correct Answer: A

Rationale: Cholesterol is a precursor for the synthesis of sex hormones like estrogen and testosterone.

Correct Answer: B

Rationale: Cardiac cachexia is a condition characterized by severe weight loss and tissue wasting. This typically occurs in patients suffering from heart failure due to an increased energy expenditure and reduced appetite, which is why choice B is the correct answer. The other choices are incorrect as they do not accurately describe the symptoms of cardiac cachexia. Decreased physical activity (choice A) can be a result of many conditions, not specifically cardiac cachexia. Poor urine output and tissue edema (choice C) are more indicative of kidney problems rather than cardiac cachexia. Finally, cardiac arrhythmia and wet lung sounds (choice D) are symptoms related to other cardiac conditions, not specifically to cardiac cachexia.

Correct Answer: D

Rationale: The first statement is incorrect because dental caries are not solely caused by sucrose. They are the result of a complex interaction of multiple factors, including the type of bacteria in the mouth, the host's diet, oral hygiene, and salivary flow. The second statement is correct as consuming sugar in moderation and limiting the frequency of sugar exposure are indeed effective strategies to prevent dental caries. Therefore, the answer is option D: The first statement is false; the second is true.

Correct Answer: D

Rationale: Carbohydrates, fats, and proteins are the three macronutrients that provide energy (calories) to the body. Carbohydrates are the body's primary source of energy, fats act as a secondary source when carbohydrate energy is exhausted, and proteins are used for energy when carbohydrate and fat sources are low. Choice D, Water, is essential for the body's functions, but it does not provide energy.

Correct Answer: C

Rationale: The correct answer is C: Choose high-fat meat instead of lean meat. High-fat meats are more calorie-dense than lean meats, which makes them a good choice for increasing calorie intake. This is crucial for patients with stomach cancer who want to avoid weight loss and wasting. Choice A is incorrect because skim milk or water contains fewer calories than whole fat milk. Choice B is also incorrect because peanut butter and nuts are high in calories and therefore should not be avoided when trying to increase calorie intake. Finally, choice D is not a good suggestion to increase calorie intake as alcohol does not provide the necessary nutrients needed for a balanced diet. In fact, excessive alcohol can harm the liver and other organs, and it's not a reliable source of calories.

Correct Answer: C

Rationale: Atherosclerosis is dangerous to arterial function because it narrows the arterial lumen, increasing the risk of a clot completely blocking the blood flow. This can lead to severe cardiovascular events such as heart attacks or strokes. Choice A is incorrect since atherosclerosis does not primarily diminish central circulation, but rather, it impedes local blood flow where the plaque is present. Choice B is also incorrect as atherosclerosis increases the pressure on artery walls due to the narrowed space for blood flow, not decrease it. Lastly, choice D is incorrect as atherosclerosis causes the arteries to lose their elasticity, not increase it.

Correct Answer: B

Rationale: The first step in the scientific method is to make an observation and ask a question. This is because the scientific method is a systematic process of investigation that begins with observing a phenomenon or asking a question about it. This is followed by formulating a hypothesis (Choice C), designing and conducting an experiment to test the hypothesis (Choice A), and analyzing the results to reach a consensus or conclusion (Choice D). Therefore, choices A, C, and D are incorrect as they represent steps that occur after the initial observation and question.

Correct Answer: B

Rationale: All the statements above are accurate about oral exposure to fermentable carbohydrates, except for option B. In fact, longer exposure to these carbohydrates decreases the opportunity for remineralization. This is because the process of demineralization, in which minerals are lost from the tooth enamel, is sped up by the presence of fermentable carbohydrates. The Stephan curve (option C) is a graph that demonstrates how the pH of dental plaque changes after a sugar rinse, usually dropping (becoming more acidic), which can lead to enamel decalcification. Option D is also accurate, as a pH of 5.5 or lower is the critical point at which enamel starts to decalcify.