Nursing Elites

1. 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.

2. Which of the following cations is found at the center of a heme?

• A. Cr (III)
• B. Cu (II)
• C. Iron (II)
• D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

3. What is the importance of RNA splicing?

• A. Removes introns from the mRNA molecule
• B. Adds the poly-A tail to the mRNA molecule
• C. Activates the mRNA molecule for translation
• D. Modifies the structure of the protein

Correct answer: A

Rationale: RNA splicing is a crucial process in gene expression where non-coding regions called introns are removed from the pre-mRNA molecule, and the remaining coding regions called exons are joined together to form the mature mRNA molecule. This process ensures that only the protein-coding sequences are retained in the mRNA for translation, allowing for the production of functional proteins. Therefore, option A is the correct answer as it accurately describes the importance of RNA splicing in generating mature mRNA molecules for protein synthesis. B) Adding the poly-A tail to the mRNA molecule is a post-transcriptional modification that occurs after RNA splicing and is not directly related to the process of removing introns. C) Activating the mRNA molecule for translation is typically achieved through the addition of a 5' cap and the poly-A tail, rather than through RNA splicing. D) Modifying the structure of the protein is not directly related to the process of RNA splicing, which primarily focuses on mRNA maturation by removing non-coding introns.

4. What is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division?

• A. Centromere
• B. Chromatid
• C. Chromosome
• D. Gene

Correct answer: C

Rationale: A chromosome is a rod-shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division. It contains the genetic material and is essential for cell division and replication. The centromere is a specific region of a chromosome that plays a role in cell division. A chromatid is one half of a duplicated chromosome, and a gene is a unit of heredity responsible for specific traits. Therefore, the correct answer is 'Chromosome' as it represents the entire condensed DNA molecule during cell division.

5. An object is thrown at an angle. Which of the following forces acts HORIZONTALLY on the object during its flight?

• A. Gravitational force
• B. Normal force from the ground
• C. Air resistance
• D. The force of throwing

Correct answer: C

Rationale: During the flight of the object, the only force that acts horizontally on the object is air resistance. Air resistance opposes the motion of the object through the air and acts in the direction opposite to the object's velocity. Gravitational force acts vertically downward, influencing the object's weight and vertical motion. The normal force from the ground acts perpendicular to the ground to support the object's weight. The force of throwing initially imparts velocity to the object at an angle, but it does not act horizontally throughout the flight.

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