Nokea
What is the function of the cell membrane?
- A. To protect the cell and control what enters and exits
- B. To store energy
- C. To produce proteins
- D. To synthesize lipids
Correct Answer: A
Rationale: The cell membrane, also known as the plasma membrane, serves as a protective barrier for the cell, separating the internal environment of the cell from the external environment. It is selectively permeable, meaning it controls the passage of substances in and out of the cell. This regulation of what enters and exits the cell is crucial for maintaining the cell's internal environment and ensuring proper functioning. Options B, C, and D are incorrect because storing energy, producing proteins, and synthesizing lipids are functions carried out by other cellular structures such as mitochondria, ribosomes, and endoplasmic reticulum, respectively, not the cell membrane.
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Which of the following is NOT a function of the integumentary system?
- A. Regulation of body temperature
- B. Protection from pathogens
- C. Synthesis of vitamin D
- D. Production of digestive enzymes
Correct Answer: D
Rationale: The correct answer is D. The production of digestive enzymes is not a function of the integumentary system. The integumentary system is responsible for regulating body temperature, protecting the body from pathogens, and synthesizing vitamin D. Digestive enzymes are produced by organs in the digestive system, such as the pancreas and stomach, and not by the integumentary system.
Which of the following is a characteristic of a solution with high viscosity?
- A. It flows easily
- B. It has a low resistance to flow
- C. It has a high resistance to flow
- D. It does not mix with other liquids
Correct Answer: C
Rationale: The correct answer is C: 'It has a high resistance to flow.' A solution with high viscosity exhibits a high resistance to flow. Viscosity measures the fluid's resistance to deformation or flow, with higher viscosity indicating thicker and slower-flowing fluids. Choice A is incorrect because high viscosity means the solution flows slowly, not easily. Choice B is incorrect as high viscosity implies a high resistance to flow, not a low one. Choice D is irrelevant to viscosity and does not describe a characteristic associated with high viscosity.
Which state of matter has a definite shape and volume but can flow?
- A. Solid
- B. Liquid
- C. Gas
- D. Plasma
Correct Answer: B
Rationale: A liquid is the state of matter that has a definite volume but can flow and take the shape of its container. Solids have a definite shape and volume but do not flow as liquids do. Gases do not have a definite shape or volume but can flow to fill their container. Plasma is a state of matter where the particles are highly energized and do not have a definite shape or volume, thus not fitting the description of having a definite shape and volume while being able to flow.
Which of the following organs is responsible for churning and mechanically breaking down food?
- A. Small intestine
- B. Large intestine
- C. Stomach
- D. Esophagus
Correct Answer: C
Rationale: The correct answer is C, the stomach. The stomach is responsible for churning and mechanically breaking down food. It contains muscles that contract and relax to mix food with digestive juices, breaking it down into smaller particles. This mechanical digestion process helps prepare the food for further digestion and absorption in the small intestine. The small intestine is primarily responsible for the absorption of nutrients, not for mechanical digestion. The large intestine absorbs water and salts, and the esophagus is a muscular tube that transports food from the mouth to the stomach, not involved in churning or breaking down food.
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.