Nursing Elites

1. The primary source of energy entering most ecosystems is:

• A. Chemical energy stored in bonds
• B. Thermal energy from the Earth's core
• C. Light energy from the sun
• D. Kinetic energy from wind and water

Correct answer: C

Rationale: Rationale: In most ecosystems, the primary source of energy is sunlight. This energy is captured by plants and other photosynthetic organisms through the process of photosynthesis. These organisms convert light energy into chemical energy stored in the bonds of organic molecules, such as glucose. This stored chemical energy is then passed on to other organisms in the ecosystem through the food chain, making sunlight the fundamental source of energy for most ecosystems. Thermal energy from the Earth's core (option B) is not a primary source of energy for ecosystems, as it is not readily accessible to most organisms. Kinetic energy from wind and water (option D) can play a role in some ecosystems, but it is not the primary source of energy. Chemical energy stored in bonds (option A) is a form of energy that is derived ultimately from the sun through photosynthesis.

2. Nuclear binding energy represents the energy required to:

• A. Separate an electron from its atom
• B. Separate protons and neutrons within a nucleus
• C. Cause nuclear fission
• D. Induce nuclear fusion

Correct answer: B

Rationale: Nuclear binding energy is the energy required to hold the protons and neutrons within a nucleus together. This energy is necessary to overcome the electrostatic repulsion between positively charged protons in the nucleus. Option A, separating an electron from its atom, is related to ionization energy, not nuclear binding energy. Option C, causing nuclear fission, involves splitting a heavy nucleus into smaller nuclei, releasing energy but not directly related to the binding energy. Option D, inducing nuclear fusion, involves combining two light nuclei to form a heavier nucleus, also not directly related to the energy required to hold protons and neutrons together within a nucleus.

3. What tool helps scientists identify and classify organisms based on their shared characteristics?

• A. Binomial nomenclature
• B. Cladistics
• C. Dichotomous key
• D. Domain-based classification

Correct answer: C

Rationale: Rationale: A) Binomial nomenclature is a system used to give each organism a two-part scientific name (genus and species) but does not help in identifying or classifying organisms based on shared characteristics. B) Cladistics is a method of classification based on evolutionary relationships and shared characteristics, but it is not a tool used for identifying organisms. C) Dichotomous key is a tool that helps scientists identify and classify organisms based on their shared characteristics by presenting a series of choices leading the user to the correct identification. D) Domain-based classification is a system of classification that groups organisms into three domains (Bacteria, Archaea, Eukarya) based on molecular and genetic similarities, but it is not a tool used for identifying organisms based on shared characteristics.

4. The hormone responsible for regulating blood sugar levels is produced by the:

• A. Pituitary gland
• B. Thyroid gland
• C. Pancreas
• D. Adrenal glands

Correct answer: C

Rationale: The correct answer is C: Pancreas. The hormone responsible for regulating blood sugar levels is insulin, which is produced by the pancreas. Insulin helps to lower blood sugar levels by allowing cells to take in glucose from the bloodstream. The pituitary gland (A) is known for producing various hormones that regulate other endocrine glands, while the thyroid gland (B) produces hormones that regulate metabolism. The adrenal glands (D) produce hormones such as cortisol and adrenaline, but they are not primarily responsible for regulating blood sugar levels.

5. What is the role of RNA interference in silencing genes?

• A. Increases protein production
• B. Promotes gene mutation
• C. Inhibits the expression of specific genes
• D. Repairs damaged DNA

Correct answer: C

Rationale: Rationale: RNA interference (RNAi) is a biological process that involves the silencing of gene expression by inhibiting the translation of mRNA or by degrading mRNA molecules. This mechanism plays a crucial role in regulating gene expression and can be used to selectively silence specific genes. By interfering with the expression of specific genes, RNAi can downregulate protein production from those genes. Therefore, option C, "Inhibits the expression of specific genes," is the correct role of RNA interference in silencing genes.

6. Colligative properties of solutions depend on the...

• A. Concentration of the solvent
• B. All of the 3 answers given
• C. Chemical identity of the solute
• D. Number of solute particles in solution

Correct answer: D

Rationale: The correct answer is D: 'Number of solute particles in solution.' Colligative properties, such as boiling point elevation and freezing point depression, depend on the number of solute particles present in a solution, not on the chemical identity of the solute or the concentration of the solvent. This is because the presence of solute particles disrupts the solvent's normal behavior, affecting these properties. Therefore, the number of solute particles in solution directly influences colligative properties, making it the most accurate choice among the options provided.

Similar Questions