Which of the following statements is true regarding basal metabolic rate:
**Core Concept:** Basal Metabolic Rate (BMR) is the minimum energy required by an organism to sustain vital life processes such as cell maintenance, protein synthesis, and thermoregulation. It is influenced by factors like body mass, sex, and age.
**Why the Correct Answer is Right:**
Correct Answer: D. Basal Metabolic Rate (BMR) is directly proportional to a person's body mass.
In humans, BMR is influenced by several factors including body mass index (BMI). As body mass increases, the energy requirements to sustain vital life processes also rise. This is because larger individuals require more energy to maintain their cells, synthesize proteins, and regulate body temperature.
**Why Each Wrong Option is Incorrect:**
A. False: BMR does not remain constant throughout the day. It increases during active periods and decreases during resting periods.
B. False: BMR is unrelated to an individual's age. Both young and elderly individuals have different BMR levels.
C. False: BMR is not solely dependent on an individual's sex. BMR varies among both males and females, influenced by factors like body mass and composition.
**Clinical Pearl / High-Yield Fact:**
To understand an individual's energy requirements, it is essential to consider BMR calculations based on factors like body mass. Understanding BMR aids in determining proper nutrition, exercise, and weight management plans. Adequate nutrition and regular physical activity can help maintain a healthy weight and reduce the risk of obesity-related diseases.
---
**Question:** Which of the following statements is true regarding the action of insulin:
A. Insulin stimulates gluconeogenesis
B. Insulin inhibits gluconeogenesis
C. Insulin stimulates glycogenesis
D. Insulin inhibits lipolysis
**Core Concept:** Insulin is a hormone produced by the beta cells of the pancreas, playing a vital role in regulating blood glucose levels by facilitating glucose uptake into cells and inhibiting gluconeogenesis.
**Why the Correct Answer is Right:**
Correct Answer: B. Insulin inhibits gluconeogenesis.
Insulin, as mentioned earlier, is responsible for maintaining blood glucose levels. One of its primary functions is to inhibit gluconeogenesis, which is the process of glucose production in the liver from non-carbohydrate sources, such as amino acids and glycerol. By suppressing gluconeogenesis, insulin helps maintain euglycemia (normal blood glucose levels).
**Why Each Wrong Option is Incorrect:**
A. Insulin does not stimulate gluconeogenesis; instead, it inhibits it as mentioned earlier.
C. Insulin does not stimulate glycogenesis; its primary role is to suppress gluconeogenesis and promote glucose uptake into cells.
D. Insulin does not inhibit lipolysis; it actually promotes lipogenesis (fat storage) and inhibits lipolysis (fat breakdown) to conserve glucose for essential cellular functions.
**Clinical Pearl:**
Understanding the role of insulin is essential in managing blood glucose levels. Insulin resistance or inadequate insulin secretion can lead to hyperglycemia (high blood glucose levels), which is a risk factor for