Nursing Elites

1. Which of the following is NOT a source of genetic variation in a population?

• A. Mutations in genes
• B. Genetic drift (random fluctuations in allele frequencies)
• C. Gene flow (movement of genes between populations)
• D. Blending inheritance (traits of parents are averaged in offspring)

Correct answer: D

Rationale: Rationale: A) Mutations in genes: Mutations are changes in the DNA sequence that can introduce new alleles into a population, leading to genetic variation. B) Genetic drift (random fluctuations in allele frequencies): Genetic drift refers to random changes in allele frequencies in a population, which can lead to genetic variation through chance events. C) Gene flow (movement of genes between populations): Gene flow occurs when individuals move between populations, bringing new alleles with them and increasing genetic variation within populations. D) Blending inheritance (traits of parents are averaged in offspring): Blending inheritance was a historical theory that suggested offspring inherit a blend of traits from their parents, leading to a reduction in genetic variation over time. However, this concept has been disproven by the understanding of Mendelian genetics, where traits are inherited independently and do not blend together. Therefore, blending inheritance does not contribute

2. During which stage of meiosis II are sister chromatids separated, resulting in four genetically unique daughter cells?

• A. Prophase I
• B. Prophase II
• C. Anaphase I
• D. Anaphase II

Correct answer: D

Rationale: - Prophase I occurs in meiosis I, not meiosis II. During Prophase I, homologous chromosomes pair up and exchange genetic material in a process called crossing over. - Prophase II is the stage where the nuclear envelope breaks down, and spindle fibers start to reappear, preparing the cell for division. Sister chromatids are still attached during Prophase II. - Anaphase I is the stage in meiosis I where homologous chromosomes are separated and pulled to opposite poles of the cell. - Anaphase II is the stage in meiosis II where sister chromatids are separated and pulled to opposite poles of the cell, resulting in four genetically unique daughter cells. This is the stage where the final separation of genetic material occurs, leading to the formation of haploid daughter cells.

3. Which technology allows scientists to directly edit the human genome?

• A. Polymerase Chain Reaction (PCR)
• B. Gel electrophoresis
• C. DNA sequencing
• D. CRISPR-Cas9

Correct answer: D

Rationale: CRISPR-Cas9 is the correct answer. A) Polymerase Chain Reaction (PCR) is used for amplifying specific DNA segments, not directly editing the human genome. B) Gel electrophoresis is for separating DNA fragments by size, not for genome editing. C) DNA sequencing determines DNA nucleotide order but does not directly edit the genome. D) CRISPR-Cas9 technology enables precise modifications in the DNA of organisms, including humans. It guides the Cas9 enzyme to specific genome locations for targeted edits, revolutionizing genetic research and offering various applications in gene editing and therapy. Unlike the other techniques mentioned, CRISPR-Cas9 is specifically designed to make changes in the genetic code itself, making it a powerful tool for genetic manipulation.

4. When water boils, it changes from a liquid to a gas. This is an example of a:

• A. Chemical reaction
• B. Physical change
• C. Nuclear reaction
• D. Biological process

Correct answer: B

Rationale: This is a physical change because boiling water involves a change in state from liquid to gas without altering the chemical composition of the water molecules. In a chemical reaction, new substances are formed by breaking and forming chemical bonds, which is not the case during boiling. A nuclear reaction involves changes in atomic nuclei, which are not occurring during boiling. A biological process refers to activities related to living organisms, which is not applicable to the change from liquid to gas in boiling water.

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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