Nursing Elites

1. What is the valve that prevents blood from flowing back from the left ventricle into the left atrium?

• A. Tricuspid valve
• B. Mitral valve
• C. Aortic valve
• D. Pulmonic valve

Correct answer: B

Rationale: The correct answer is the Mitral valve. The mitral valve is located between the left atrium and the left ventricle of the heart. Its function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. Choice A, the Tricuspid valve, is incorrect as it is located between the right atrium and right ventricle. Choice C, the Aortic valve, and Choice D, the Pulmonic valve, are also incorrect as they are involved in the circulation of blood leaving the heart rather than preventing backflow within the atria and ventricles.

2. Describe the mechanism by which genes are transmitted from parents to offspring.

• A. Blending of parental genes, resulting in an average of their traits.
• B. Random assortment of alleles during meiosis, leading to unique combinations in each offspring.
• C. Inheritance of solely dominant alleles, masking the influence of recessive ones.
• D. Direct transfer of both parental genomes, creating identical copies of the parents.

Correct answer: B

Rationale: A) Blending of parental genes, resulting in an average of their traits, is not an accurate description of how genes are transmitted. In reality, genes are not blended but rather passed down in discrete units. B) Random assortment of alleles during meiosis is the correct mechanism by which genes are transmitted from parents to offspring. During meiosis, homologous chromosomes separate, and alleles are randomly distributed to the gametes, leading to unique combinations of genes in each offspring. C) Inheritance of solely dominant alleles, masking the influence of recessive ones, is not an accurate representation of gene transmission. Offspring inherit alleles from both parents, and the expression of dominant or recessive traits depends on the specific combination of alleles. D) Direct transfer of both parental genomes, creating identical copies of the parents, is not how genes are transmitted. Offspring inherit a unique combination

3. What are the two main types of nuclear decay, and what differentiates them?

• A. Fission and fusion, based on the size of the nucleus
• B. Alpha and beta decay, based on the emitted particle
• C. Spontaneous and induced decay, based on the trigger
• D. Isotope decay and chain reactions, based on the stability of the nucleus

Correct answer: B

Rationale: The correct answer is B. The two main types of nuclear decay are alpha and beta decay, which are differentiated based on the emitted particle. In alpha decay, an alpha particle (consisting of two protons and two neutrons) is emitted from the nucleus, while in beta decay, a beta particle (either an electron or a positron) is emitted. These decay types are distinguished by the particles they emit, not by the size of the nucleus, trigger, or stability of the nucleus. Choices A, C, and D are incorrect because fission, fusion, spontaneous, induced, isotope decay, and chain reactions are different processes in nuclear physics and do not represent the two main types of nuclear decay based on emitted particles.

4. How does the Law of Conservation of Mass apply to this reaction: 2H₂ + O₂ → 2H₂O?

• A. Electrons are not lost.
• B. The hydrogen does not lose mass.
• C. New water molecules are formed.
• D. There is no decrease or increase in matter.

Correct answer: D

Rationale: The Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction. In the given reaction, 2 moles of hydrogen combine with 1 mole of oxygen to form 2 moles of water. The total mass of the reactants (hydrogen and oxygen) is equal to the total mass of the products (water), meaning there is no decrease or increase in matter. The total mass of the system remains constant, demonstrating the conservation of mass. Choices A, B, and C are incorrect because the conservation of mass does not specifically relate to electrons, individual elements (like hydrogen), or the formation of new molecules; instead, it focuses on the overall mass of the system before and after the reaction.

5. What checkpoint mechanism ensures all chromosomes are attached to the spindle fibers before anaphase begins?

• A. Prometaphase
• B. Metaphase
• C. Cyclin degradation
• D. Sister chromatid cohesion

Correct answer: A

Rationale: A) Prometaphase is the correct answer because it is the stage of mitosis where all chromosomes are attached to the spindle fibers before anaphase begins. During prometaphase, the nuclear envelope breaks down, allowing the spindle fibers to attach to the kinetochores of the chromosomes. This attachment is necessary for proper chromosome alignment and segregation during anaphase. B) Metaphase is incorrect because it is the stage where chromosomes are aligned at the metaphase plate but do not necessarily have all spindle fibers attached. C) Cyclin degradation is incorrect because it is a regulatory mechanism that controls the progression of the cell cycle but is not specifically related to ensuring all chromosomes are attached to spindle fibers. D) Sister chromatid cohesion is incorrect because it refers to the physical connection between sister chromatids that is maintained until anaphase, but it does not ensure that all chromosomes are attached to spindle fibers.

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