Nursing Elites

1. What is the purpose of a catalyst?

• A. To increase a reaction rate by increasing the activation energy
• B. To increase a reaction rate by increasing the temperature
• C. To increase a reaction rate by decreasing the activation energy
• D. To increase a reaction rate by decreasing the temperature

Correct answer: C

Rationale: The purpose of a catalyst is to increase a reaction's rate by decreasing the activation energy required for the reaction to occur. This allows the reaction to proceed more quickly without being consumed in the process. The catalyst provides an alternate mechanism with a lower activation energy, making it easier for the reactants to convert into products. Choice A is incorrect because a catalyst lowers, not increases, the activation energy. Choice B is incorrect because a catalyst does not affect the temperature directly but provides an alternative pathway for the reaction to occur more easily. Choice D is incorrect because a catalyst does not lower the temperature but facilitates the reaction by lowering the activation energy barrier. Therefore, the correct answer is C, 'To increase a reaction rate by decreasing the activation energy.'

2. What type of inheritance pattern results in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation?

• A. Incomplete dominance
• B. Codominance
• C. Sex-linked inheritance
• D. Autosomal dominant inheritance

Correct answer: D

Rationale: Autosomal dominant inheritance results in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. This inheritance pattern occurs when a single copy of the dominant allele is enough to express the dominant phenotype. A) Incomplete dominance: In incomplete dominance, the heterozygous phenotype is a blend of the two homozygous phenotypes, and it does not lead to a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. B) Codominance: In codominance, both alleles are fully expressed in the heterozygous phenotype, but this pattern also does not result in a 3:1 ratio of dominant to recessive phenotypes in the F2 generation. C) Sex-linked inheritance: Sex-linked inheritance involves genes located on the sex chromosomes and does not typically lead to a 3:1 ratio of dominant to recessive phenotypes in the F2 generation.

3. In meiosis, how many divisions occur, and how many daughter cells are produced?

• A. One division, two daughter cells
• B. Two divisions, four daughter cells
• C. Four divisions, eight daughter cells
• D. Eight divisions, sixteen daughter cells

Correct answer: B

Rationale: In meiosis, there are two divisions: meiosis I and meiosis II. During meiosis I, homologous chromosomes separate, resulting in two daughter cells with half the number of chromosomes as the parent cell. In meiosis II, sister chromatids separate, resulting in a total of four daughter cells, each with a haploid set of chromosomes. Therefore, meiosis involves two divisions and produces four daughter cells. Choice A is incorrect because meiosis involves two divisions, not one. Choice C and D are incorrect as meiosis does not go through four or eight divisions, resulting in eight or sixteen daughter cells.

4. 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.

5. What is the microscopic functional unit of the kidney responsible for filtering blood?

• A. Ureter
• B. Nephron
• C. Renal pelvis
• D. Bladder

Correct answer: B

Rationale: The nephron is the correct answer as it is the microscopic functional unit of the kidney responsible for filtering blood. It is composed of a renal corpuscle (glomerulus and Bowman's capsule) and a renal tubule. The other options, such as (A) Ureter, (C) Renal pelvis, and (D) Bladder, do not play a role in filtering blood within the kidney. The ureter is a tube that carries urine from the kidney to the bladder. The renal pelvis is a part of the kidney where urine collects before entering the ureter. The bladder is an organ that stores urine until it is excreted from the body.

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