Nursing Elites

1. Which term is used to classify reactions that require light energy to proceed?

• A. Combustion reactions
• B. Endothermic reactions
• C. Photochemical reactions
• D. Double displacement reactions

Correct answer: C

Rationale: Reactions that require light energy to proceed are classified as photochemical reactions. Photochemical reactions involve the absorption of light energy to initiate a chemical reaction. Combustion reactions involve the rapid combination of a substance with oxygen, endothermic reactions absorb heat from the surroundings, and double displacement reactions involve the exchange of ions between two compounds. Therefore, the correct term for reactions requiring light energy is 'photochemical reactions,' making option C the correct answer.

2. Through which part of the digestive system are nutrients absorbed into the bloodstream?

• A. Stomach
• B. Large intestine
• C. Small intestine
• D. Esophagus

Correct answer: C

Rationale: The small intestine is the primary site of nutrient absorption in the digestive system. It is where the majority of digestion and absorption of nutrients such as carbohydrates, proteins, and fats occurs. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which increase the surface area available for absorption. Nutrients are absorbed through the walls of the small intestine and into the bloodstream to be transported to cells throughout the body. The stomach's main role is to break down food through the action of stomach acids and enzymes but does not absorb nutrients. The large intestine primarily absorbs water and electrolytes from the remaining indigestible food matter, and the esophagus is a muscular tube that transports food from the mouth to the stomach, without being involved in nutrient absorption.

3. How can a single gene mutation lead to multiple phenotypes depending on the organism?

• A. Pleiotropy describes the effect of one gene influencing multiple seemingly unrelated traits.
• B. Epigenetics involves environmental factors modifying gene expression without altering the DNA sequence.
• C. Genetic drift refers to random changes in allele frequencies within a population.
• D. Gene regulation controls the timing and level of gene expression within an organism.

Correct answer: A

Rationale: A single gene mutation can lead to multiple phenotypes through pleiotropy, where one gene influences diverse traits or functions in an organism. This phenomenon occurs when the mutated gene affects different biochemical pathways, developmental processes, or cellular functions, resulting in a cascade of downstream effects that manifest as a variety of phenotypic outcomes. Choice B, epigenetics, involves modifications in gene expression influenced by environmental factors without altering the DNA sequence, which is not directly related to the question about single gene mutations causing multiple phenotypes. Choice C, genetic drift, refers to random changes in allele frequencies within a population, which is unrelated to the impact of a single gene mutation on multiple phenotypes. Choice D, gene regulation, focuses on controlling the timing and level of gene expression within an organism, which is not directly addressing how a single gene mutation can lead to diverse phenotypes.

4. Which of the following is NOT a type of vaccine?

• A. Live attenuated vaccine
• B. Toxoid vaccine
• C. Conjugate vaccine
• D. Antibiotic

Correct answer: D

Rationale: A) Live attenuated vaccine: This type of vaccine contains a weakened form of the virus or bacteria that causes the disease. When administered, it stimulates an immune response without causing the disease itself. B) Toxoid vaccine: Toxoid vaccines are made from toxins produced by bacteria that have been inactivated. They stimulate the immune system to produce antibodies against the toxin, providing immunity against the disease. C) Conjugate vaccine: Conjugate vaccines are made by combining a weak antigen with a strong antigen to enhance the immune response. They are commonly used to protect against bacterial infections. D) Antibiotic: Antibiotics are medications used to treat bacterial infections by killing or inhibiting the growth of bacteria. They are not a type of vaccine but rather a class of antimicrobial drugs. Therefore, the correct answer is D) Antibiotic, as it is not a type of vaccine.

5. Which part of the brain regulates body temperature, hunger, and thirst?

• A. Cerebellum
• B. Hypothalamus
• C. Thalamus
• D. Medulla oblongata

Correct answer: B

Rationale: The correct answer is the Hypothalamus. The hypothalamus is a crucial part of the brain that regulates various essential functions to maintain homeostasis. It controls body temperature, hunger, thirst, and plays a key role in the autonomic nervous system. The cerebellum is primarily involved in coordinating movement and balance, the thalamus acts as a relay station for sensory information, and the medulla oblongata is responsible for vital functions like breathing and heart rate. Therefore, choices A, C, and D are incorrect as they do not govern the specific functions mentioned in the question.

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