Nursing Elites

1. Where does mRNA translation typically occur?

• A. On the ribosome
• B. In the nucleus
• C. In the cytoplasm
• D. On the smooth endoplasmic reticulum

Correct answer: A

Rationale: mRNA translation typically occurs on the ribosome. Ribosomes are the cellular machinery responsible for protein synthesis. They read the mRNA sequence and assemble amino acids into a polypeptide chain during translation. The correct answer is A. Choices B, C, and D are incorrect. The nucleus is where mRNA is transcribed from DNA, while translation occurs in the cytoplasm on ribosomes. The smooth endoplasmic reticulum is involved in protein processing and transport but not in mRNA translation.

2. During which of the following stages does crossing over occur?

• A. Mitosis Prophase
• B. Meiosis Prophase I
• C. Meiosis Prophase II
• D. Interphase

Correct answer: B

Rationale: Crossing over occurs during Prophase I of meiosis. This stage is specifically associated with genetic recombination, where homologous chromosomes exchange genetic material. This process contributes to genetic diversity by creating new combinations of alleles. Choices A, C, and D are incorrect. In mitosis, crossing over does not occur as it involves the separation of replicated chromosomes. Meiosis Prophase II is focused on the reformation of nuclei and does not involve crossing over. Interphase is a stage where the cell prepares for division and is not associated with crossing over.

3. Which of the following describes how atomic radius varies across the periodic table?

• A. Atomic radius increases from top to bottom and left to right on the periodic table.
• B. Atomic radius increases from top to bottom and right to left on the periodic table.
• C. Atomic radius increases from top to bottom and toward the halogens on the periodic table.
• D. Atomic radius increases from top to bottom and toward the noble gases on the periodic table.

Correct answer: A

Rationale: Atomic radius tends to increase from top to bottom and left to right on the periodic table. This is because as you move down a group (top to bottom), new energy levels are added, increasing the distance of the outer electrons from the nucleus and thus increasing the size of the atom. On the other hand, as you move from left to right across a period, the number of protons and electrons increases, leading to a stronger nuclear charge that attracts the electrons closer to the nucleus, resulting in smaller atomic radii. Choice B is incorrect as atomic radius does not increase from right to left. Choices C and D are incorrect as they incorrectly associate the trend with specific groups of elements (halogens and noble gases) rather than the general trend observed on the periodic table.

4. Which of the following is a type of white blood cell that plays a key role in adaptive immunity by seeking out, attacking, and destroying targeted pathogens?

• A. memory B cells
• B. neutrophils
• C. antibodies
• D. cytotoxic T cells

Correct answer: D

Rationale: The correct answer is cytotoxic T cells. Cytotoxic T cells are a type of white blood cell that is crucial in adaptive immunity. They are specialized in recognizing and destroying infected or abnormal cells in the body. Neutrophils are primarily involved in innate immunity, providing rapid response to infections. Antibodies are proteins produced by B cells and are essential in specific immune responses, but they do not directly attack pathogens. Memory B cells are part of the adaptive immune response, responsible for mounting a quicker and stronger response upon re-exposure to a pathogen. However, they do not directly seek out and destroy pathogens like cytotoxic T cells do.

5. Melatonin is a hormone produced by the pineal gland. What is its primary function?

• A. Regulate blood pressure
• B. Stimulate the digestive system
• C. Control sleep-wake cycles
• D. Maintain bone density

Correct answer: C

Rationale: Melatonin is primarily known for its role in controlling sleep-wake cycles. It is produced by the pineal gland in response to darkness, helping signal the body that it is time to sleep. Melatonin levels typically rise in the evening and stay elevated throughout the night, promoting sleep. Choices A, B, and D are incorrect as melatonin's primary function is not to regulate blood pressure, stimulate the digestive system, or maintain bone density. While melatonin may have some indirect effects on these functions, its main role lies in regulating the circadian rhythm and promoting a restful sleep cycle.

Similar Questions