Nursing Elites

1. An atom has 2 protons, 4 neutrons, and 2 electrons. What is the approximate atomic mass of this atom?

• A. 2
• B. 4
• C. 6
• D. 8

Correct answer: D

Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 2 protons and 4 neutrons, totaling 6 particles in the nucleus. Therefore, the approximate atomic mass of this atom is 6, making choice C incorrect. The number of electrons does not significantly contribute to the atomic mass, as they are much lighter and located in the electron cloud surrounding the nucleus. Choices A, B, and C are incorrect as they do not reflect the correct calculation of atomic mass based on protons and neutrons only.

2. What is the role of transfer RNA (tRNA) in protein synthesis?

• A. Transcribes DNA into mRNA
• B. Decodes the genetic code on mRNA
• C. Carries specific amino acids to the ribosomes
• D. Modifies the structure of proteins

Correct answer: C

Rationale: A) Transcribes DNA into mRNA: This is the function of RNA polymerase, not transfer RNA (tRNA). tRNA is involved in protein synthesis, not transcription. B) Decodes the genetic code on mRNA: This is the function of tRNA during translation. tRNA molecules carry specific amino acids and recognize the codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain. C) Carries specific amino acids to the ribosomes: This is the primary role of tRNA in protein synthesis. Each tRNA molecule is specific for a particular amino acid and carries it to the ribosome, where it is added to the growing protein chain. D) Modifies the structure of proteins: This is not a function of tRNA. Protein modification can occur after translation is complete and involves other cellular processes and molecules.

3. What is the process of splitting a heavy nucleus into smaller nuclei, releasing a vast amount of energy called?

• A. Nuclear fusion
• B. Nuclear fission
• C. Radioactive decay
• D. Chain reaction

Correct answer: B

Rationale: The correct answer is B: Nuclear fission. Nuclear fission is the process of splitting a heavy nucleus into smaller nuclei, releasing a vast amount of energy. This process is commonly used in nuclear power plants and nuclear weapons. It is a controlled chain reaction that generates energy. Option A, Nuclear fusion, is the process of combining two light nuclei to form a heavier nucleus, releasing energy. This process powers the sun and other stars. Option C, Radioactive decay, is the process by which an unstable atomic nucleus loses energy by emitting radiation. Option D, Chain reaction, is a self-sustaining reaction where the products of one reaction event stimulate further reaction events. While chain reactions can occur in both nuclear fission and fusion, the specific process of splitting a heavy nucleus into smaller ones is known as nuclear fission.

4. What is apoptosis, and how is it involved in embryonic development?

• A. Uncontrolled cell growth
• B. Programmed cell death
• C. DNA replication
• D. Cell division

Correct answer: B

Rationale: Apoptosis is the process of programmed cell death, not uncontrolled cell growth (Choice A). It plays a vital role in embryonic development by eliminating unnecessary or damaged cells, sculpting organs, and ensuring proper tissue organization. Through apoptosis, the embryo undergoes controlled cell death to shape structures accurately. This mechanism is essential for the precise development of organs and tissues, emphasizing the significance of apoptosis in embryogenesis. DNA replication (Choice C) and cell division (Choice D) are essential cellular processes but are not directly related to apoptosis or its role in embryonic development.

5. Which of the following is NOT a mechanism that can directly cause evolution by natural selection?

• A. Mutations in genes
• B. Differential survival and reproduction based on traits
• C. Inheritance of acquired characteristics (like strong muscles from working out)
• D. Competition for resources in an environment

Correct answer: C

Rationale: A) Mutations in genes can introduce new genetic variations into a population, which can be acted upon by natural selection. B) Differential survival and reproduction based on traits is a key component of natural selection, as individuals with advantageous traits are more likely to survive and pass on their genes to the next generation. C) Inheritance of acquired characteristics, also known as Lamarckism, is not a mechanism of evolution by natural selection. Traits acquired during an individual's lifetime (such as strong muscles from working out) are not passed on to offspring. D) Competition for resources in an environment can drive natural selection by favoring individuals with traits that help them better compete for limited resources. Therefore, the correct answer is C) Inheritance of acquired characteristics (like strong muscles from working out), as it is not a mechanism that can directly cause evolution by natural selection.

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