how do organisms maintain homeostasis

ATI TEAS 7

ATI TEAS Science

1. How do organisms maintain homeostasis?

A. By increasing their body temperature, blood pH, and fluid balance.
B. By undergoing biochemical processes and absorbing energy to increase entropy.
C. By undergoing biochemical processes to maintain the order of their external environment.
D. By using free energy and matter via biochemical processes to work against entropy.

Correct answer: D

Rationale: Organisms maintain homeostasis by utilizing free energy and matter through biochemical processes to counteract entropy, which helps in preserving internal stability. This process involves maintaining a balance within the organism's internal environment despite external changes, ensuring proper functioning and survival. Choice A is incorrect because increasing body temperature, blood pH, and fluid balance alone do not define the comprehensive process of maintaining homeostasis. Choice B is incorrect as absorbing energy to increase entropy goes against the concept of maintaining internal stability. Choice C is incorrect as maintaining the order of the external environment does not directly contribute to the organism's internal stability and balance.

2. Why does a prism separate white light into its constituent spectral components?

A. It absorbs certain colors
B. Different colors experience varying speeds within the prism
C. It bends all colors with the same magnitude
D. It reflects specific colors

Correct answer: B

Rationale: A prism separates white light into its constituent spectral components because different colors experience varying speeds within the prism due to their different wavelengths. This causes the light to refract at different angles, resulting in the separation of colors. When light enters the prism, it undergoes dispersion, where different colors are refracted at different angles due to their unique wavelengths. This phenomenon is known as chromatic dispersion. Choice A is incorrect because a prism does not absorb colors but refracts and disperses them. Choice C is incorrect because a prism refracts different colors at different angles, not with the same magnitude. Choice D is incorrect because a prism does not reflect colors but refracts and disperses them based on their wavelengths.

3. What is the atomic number of an element?

A. The number of protons in an atom's nucleus.
B. The number of neutrons in an atom's nucleus.
C. The number of electrons in an atom's valence shell.
D. The number of isotopes of an element.

Correct answer: A

Rationale: The atomic number of an element is the number of protons in an atom's nucleus. This number is crucial as it determines the element's identity and its position on the periodic table. Option B is incorrect because the number of neutrons can vary in isotopes but is not the atomic number. Option C is incorrect as the number of electrons in an atom's valence shell can vary based on the element's charge, not defining the atomic number. Option D is also incorrect because the number of isotopes is not the atomic number of an element.

4. Which hormone is responsible for regulating the body's metabolism?

A. Insulin
B. Thyroxine
C. Melatonin
D. Adrenaline

Correct answer: B

Rationale: Thyroxine, also known as T4, is produced by the thyroid gland and plays a vital role in regulating the body's metabolism. Insulin is not responsible for regulating metabolism; instead, it helps regulate blood sugar levels. Melatonin is involved in regulating sleep-wake cycles, not metabolism. Adrenaline, also known as epinephrine, is a stress hormone that prepares the body for fight or flight responses, not primarily involved in metabolic regulation.

5. What is the difference between polygenic inheritance and pleiotropy?

A. Polygenic inheritance involves multiple genes influencing one trait, while pleiotropy involves one gene affecting multiple traits.
B. Polygenic inheritance is found in simple Mendelian traits, while pleiotropy is found in complex traits.
C. Polygenic inheritance is always quantitative, while pleiotropy can be qualitative or quantitative.
D. Both involve multiple genes and multiple traits, but the specific mechanisms differ

Correct answer: A

Rationale: - Polygenic inheritance refers to the situation where a trait is influenced by multiple genes, each contributing a small effect to the phenotype. These traits often show continuous variation and are not easily categorized into discrete categories. - Pleiotropy, on the other hand, occurs when a single gene influences multiple, seemingly unrelated traits. This means that a mutation in one gene can lead to multiple phenotypic effects across different traits or characteristics. - Therefore, the key difference between polygenic inheritance and pleiotropy lies in the number of genes involved in influencing a trait (multiple genes in polygenic inheritance vs. one gene in pleiotropy) and the direction of influence (one trait affected by multiple genes in polygenic inheritance vs. multiple traits affected by one gene in pleiotropy).