Nokea
What is the primary purpose of control rods within a nuclear reactor?
- A. Reflecting neutrons back into the core
- B. Absorbing excess neutrons to control criticality
- C. Moderating the velocity of neutrons
- D. All of the above
Correct Answer: B
Rationale: The primary purpose of control rods in a nuclear reactor is to absorb excess neutrons to control criticality. When inserted into the reactor core, control rods absorb neutrons, reducing the number available for sustaining the fission chain reaction. This action allows operators to manage the reactor power levels and prevent overheating or runaway reactions. Reflecting neutrons back into the core and moderating neutron velocity are not the primary functions of control rods in a nuclear reactor. Choice A is incorrect because control rods do not reflect neutrons back into the core but absorb them. Choice C is incorrect as the moderation of neutron velocity is typically achieved by other materials like a moderator (e.g., water, graphite) rather than control rods. Choice D is incorrect as control rods do not reflect neutrons or moderate neutron velocity, making it an incorrect option.
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What is the scientific name for the building blocks of proteins?
- A. Residues
- B. Monomers
- C. Macromolecules
- D. Peptides
Correct Answer: B
Rationale: Rationale:
- Proteins are made up of long chains of amino acids.
- Amino acids are the building blocks of proteins and are considered monomers.
- Monomers are the individual units that can be linked together to form larger molecules called polymers.
- In the context of proteins, amino acids are the monomers that are linked together through peptide bonds to form polypeptide chains, which then fold into functional proteins.
- Residues refer to the specific amino acids within a protein after certain modifications or cleavages have occurred, so it is not the correct term for the building blocks of proteins.
- Macromolecules are large molecules made up of smaller subunits, such as proteins, nucleic acids, and carbohydrates, but they are not the specific building blocks of proteins.
- Peptides are short chains of amino acids linked by peptide bonds, but they are not the fundamental building blocks of proteins.
A car is moving in a circle at a constant speed. Which of the following is NOT true about its motion?
- A. It has a constant centripetal acceleration
- B. Its tangential velocity remains constant
- C. It experiences a force directed towards the center of the circle
- D. It covers the same distance in equal time intervals along its circular path
Correct Answer: B
Rationale: In circular motion at a constant speed, the car has a constant centripetal acceleration (choice A), experiences a force directed towards the center of the circle (choice C), and covers the same distance in equal time intervals along its circular path (choice D). However, the tangential velocity of an object in circular motion at a constant speed changes continuously as it moves around the circle, so it is not constant (choice B). The change in tangential velocity allows the car to maintain its motion in a circular path despite moving at a constant speed. Choice A is incorrect because centripetal acceleration is indeed present to keep the car moving in a circular path. Choice C is incorrect as a force towards the center is required to keep the car in circular motion. Choice D is incorrect because the car covers equal distances in equal time intervals to maintain its circular trajectory.
Which term refers to the act of inhaling foreign objects into the airway?
- A. Expiration
- B. Respiration
- C. Aspiration
- D. Inhalation
Correct Answer: C
Rationale: Among the options provided, aspiration is the term that specifically refers to the act of inhaling foreign objects into the airway. Expiration refers to breathing out, respiration is the overall process of gas exchange in the body, and inhalation is the act of breathing in air or other substances into the lungs. Therefore, the correct answer is C, aspiration. It is crucial to understand these terms in the context of airway management and respiratory care to ensure proper identification and treatment of related conditions.
Which of the following is NOT a function of the skeletal system?
- A. Support and structure
- B. Production of red blood cells
- C. Storage of minerals like calcium
- D. Insulation of the body
Correct Answer: D
Rationale: The skeletal system's primary functions include support and structure, protection of internal organs, movement facilitation, production of blood cells, and storage of minerals like calcium. Insulation of the body is not a function of the skeletal system. Insulation, typically involving fat under the skin, helps regulate body temperature but is not a direct function of the skeletal system. Choice B, the production of red blood cells, is a function of the skeletal system as it occurs in the bone marrow within the bones. Choices A and C are also correct functions of the skeletal system.
What is the end result of mitosis in animal cells?
- A. The production of two identical daughter cells
- B. The production of four haploid cells
- C. The production of a single diploid cell
- D. The production of a single haploid cell
Correct Answer: A
Rationale: Mitosis is a type of cell division specific to eukaryotic cells that results in the production of two identical daughter cells, each with the same genetic material as the parent cell. This process is crucial for growth, tissue repair, and maintaining a constant number of chromosomes in multicellular organisms. During mitosis, the replicated chromosomes are segregated into two separate nuclei, followed by the division of the cell into two identical daughter cells. Options B, C, and D are incorrect as mitosis does not lead to the production of four haploid cells, a single diploid cell, or a single haploid cell. The correct answer is A because mitosis results in the formation of two daughter cells that are genetically identical to each other and to the parent cell, allowing for growth and replacement of damaged cells in multicellular organisms.