Nokea
Which of the following statements is correct regarding the pH scale?
- A. A substance with a pH of 3 is more acidic than a substance with a pH of 4.
- B. A substance with a pH of 3 is two times more alkaline than a substance with a pH of 4.
- C. A substance with a pH of 3 is 10 times more alkaline than a substance with a pH of 4.
- D. A substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4.
Correct Answer: D
Rationale: The correct answer is D. The pH scale measures the acidity or basicity of a substance on a scale of 0 to 14. Each whole pH value below 7 is ten times more acidic than the next higher value. Therefore, a substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4. The difference in pH values indicates the concentration of hydrogen ions in the substance, with lower pH values representing higher acidity and higher pH values representing higher basicity.
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Emphysema caused by damage to alveoli from toxins and pollutants is likely to result in the body having difficulty performing which of the following actions?
- A. Exchanging oxygen and carbon dioxide
- B. Absorbing food
- C. Releasing histamine and acetylcholine
- D. Producing enzymes
Correct Answer: A
Rationale: Emphysema is a condition that damages the alveoli in the lungs, leading to the loss of elasticity and reduced surface area for gas exchange. As a result, individuals with emphysema have difficulty in exchanging oxygen and carbon dioxide efficiently. The damage impairs the lung's ability to transfer oxygen from the air into the bloodstream and remove carbon dioxide from the body. Absorbing food (B), releasing histamine and acetylcholine (C), and producing enzymes (D) are not directly affected by emphysema.
Which of the following properties of water explains its solvent abilities for certain substances?
- A. High specific heat
- B. Polarity
- C. Volume
- D. High surface tension
Correct Answer: B
Rationale: The correct answer is B: Polarity. Water's polarity, resulting from its unequal sharing of electrons and the formation of hydrogen bonds, makes it an excellent solvent. The polar nature of water allows it to interact with and dissolve substances that have charges or partial charges, aiding in their breakdown at a molecular level. Choices A, C, and D are not directly associated with water's solvent capabilities. High specific heat (Choice A) refers to water's ability to resist temperature changes, volume (Choice C) is the amount of space occupied by water, and high surface tension (Choice D) pertains to water's cohesive properties.
Which of the following structures is present in both prokaryotic and eukaryotic cells?
- A. Cell membrane
- B. Chromoplast
- C. Golgi apparatus
- D. Endoplasmic reticulum
Correct Answer: A
Rationale: The correct answer is the cell membrane (choice A). The cell membrane is a vital structure present in both prokaryotic and eukaryotic cells. It plays a crucial role as a selectively permeable barrier, controlling the movement of substances into and out of the cell. On the other hand, chromoplasts, Golgi apparatus, and endoplasmic reticulum are specific organelles found only in eukaryotic cells. Chromoplasts are responsible for pigment synthesis, Golgi apparatus is involved in protein processing and packaging, and endoplasmic reticulum is crucial for lipid synthesis and protein folding. Therefore, the cell membrane is the correct choice as it is the common feature shared by both prokaryotic and eukaryotic cells.
Which of the following organs is covered by the pleura, a connective tissue sheath?
- A. spleen
- B. lungs
- C. heart
- D. liver
Correct Answer: B
Rationale: The pleura is a protective membrane that covers the lungs. It consists of two layers: the visceral pleura (inner layer) and the parietal pleura (outer layer). The pleural space between these layers contains a small amount of fluid that helps reduce friction during breathing movements. The spleen, heart, and liver are not covered by the pleura. Therefore, the correct answer is the lungs.
Which of the following vessels carries oxygenated blood?
- A. Pulmonary vein
- B. Superior vena cava
- C. Pulmonary artery
- D. Inferior vena cava
Correct Answer: A
Rationale: The correct answer is A, the pulmonary vein. The pulmonary vein carries oxygenated blood from the lungs back to the heart. It is crucial to differentiate between the pulmonary vein, which carries oxygenated blood, and the pulmonary artery, which carries deoxygenated blood. This understanding is fundamental in comprehending the flow of oxygen-rich and oxygen-poor blood within the cardiovascular system.