Nokea
The muscular diaphragm plays a vital role in respiration. When it contracts, it:
- A. Increases lung volume for inhalation
- B. Decreases lung volume for exhalation
- C. Filters dust and particles from inhaled air
- D. Produces mucus to lubricate the airways
Correct Answer: A
Rationale: The muscular diaphragm plays a crucial role in respiration by contracting and flattening during inhalation. This action increases the volume of the thoracic cavity, which leads to a decrease in pressure within the lungs, allowing air to rush in and fill the expanded space. Choice B is incorrect because the diaphragm contracting increases the lung volume for inhalation, not decreases it for exhalation. Choice C is incorrect as the role of filtering dust and particles is primarily performed by the respiratory system's other structures like the nasal passages and the mucous membranes. Choice D is incorrect as mucus production is mainly carried out by specialized cells in the respiratory system and not by the diaphragm.
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Which part of the neuron receives signals from other neurons and conducts them toward the cell body?
- A. Axon
- B. Dendrite
- C. Synapse
- D. Myelin sheath
Correct Answer: B
Rationale: The dendrites are the part of the neuron that receives signals from other neurons and conducts them toward the cell body. They play a crucial role in gathering incoming signals and transmitting them to the cell body for processing. The axon, on the other hand, is responsible for carrying signals away from the cell body. The synapse is the point of connection between two neurons facilitating communication, while the myelin sheath is a protective layer surrounding the axon that aids in accelerating signal transmission.
A pendulum swings back and forth. What type of energy conversion occurs during its motion?
- A. Potential energy to kinetic energy and vice versa
- B. Thermal energy to mechanical energy and vice versa
- C. Chemical energy to electrical energy and vice versa
- D. Nuclear energy to radiant energy and vice versa
Correct Answer: A
Rationale: As the pendulum swings back and forth, it undergoes a continuous conversion between potential energy (at the highest point of the swing) and kinetic energy (at the lowest point of the swing). At the highest point, the pendulum has maximum potential energy due to its height above the ground. As it swings down, this potential energy is converted into kinetic energy, which is the energy of motion. At the lowest point of the swing, the pendulum has maximum kinetic energy and minimal potential energy. The process repeats as the pendulum swings back in the opposite direction, demonstrating the conversion between potential and kinetic energy. Choices B, C, and D are incorrect because the energy conversion in a swinging pendulum primarily involves changes between potential and kinetic energy, not thermal, chemical, electrical, nuclear, or radiant energy.
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.
What is a reaction between an acid and a base known as?
- A. Precipitation
- B. Neutralization
- C. Oxidation-reduction
- D. Photolysis
Correct Answer: B
Rationale: The correct answer is B: Neutralization. When an acid and a base react, they neutralize each other's properties, resulting in the formation of water and a salt. Choice A, 'Precipitation,' refers to the formation of a solid from a solution during a chemical reaction. Choice C, 'Oxidation-reduction,' involves the transfer of electrons between reactants. Choice D, 'Photolysis,' is a reaction where a compound is broken down into smaller components by light energy. Therefore, the most appropriate term for a reaction between an acid and a base is neutralization.
The gradual change in a species over time is called:
- A. Adaptation
- B. Evolution
- C. Speciation
- D. Natural selection
Correct Answer: B
Rationale: - Adaptation refers to the process by which a species becomes better suited to its environment over time. While adaptation is a component of evolution, it specifically refers to the changes that help a species survive and reproduce in its environment.
- Speciation is the process by which new species arise from a single ancestral species. It involves the evolution of reproductive isolation between populations.
- Natural selection is a mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce, leading to the increase in frequency of those traits in a population.
- Evolution is the gradual change in a species over time, encompassing all the processes such as adaptation, speciation, and natural selection that drive these changes.