Nokea
Bone is primarily composed of which of the following inorganic materials?
- A. calcium
- B. magnesium
- C. collagen
- D. potassium
Correct Answer: A
Rationale: Bone is primarily composed of calcium, making up about 70% of its inorganic content. Calcium is essential for bone strength and structure, playing a key role in maintaining bone health. Choice B, magnesium, while important for bone health, is found in smaller amounts in bones compared to calcium. Choice C, collagen, is a protein and is a major organic component of bone, not an inorganic material. Choice D, potassium, is an essential mineral for various bodily functions but is not a primary inorganic material found in bones.
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Which of the following cell organelles is the site of lipid synthesis?
- A. smooth endoplasmic reticulum
- B. ribosome
- C. rough endoplasmic reticulum
- D. Golgi apparatus
Correct Answer: A
Rationale: The correct answer is the smooth endoplasmic reticulum. This organelle lacks ribosomes on its surface, unlike the rough endoplasmic reticulum, which is involved in protein synthesis. The enzymes present in the smooth endoplasmic reticulum are responsible for synthesizing lipids such as phospholipids and steroids. Choice B, ribosomes, are responsible for protein synthesis and not lipid synthesis. Choice C, rough endoplasmic reticulum, is involved in protein synthesis due to the presence of ribosomes. Choice D, Golgi apparatus, is responsible for modifying, sorting, and packaging proteins for secretion, not lipid synthesis.
Which of the following Mendelian laws describes how pairs of alleles within genes separate and recombine independently from other genes?
- A. law of segregation
- B. law of dominance
- C. law of independent assortment
- D. law of predictive traits
Correct Answer: C
Rationale: The law of independent assortment describes how alleles of different genes segregate independently during gamete formation. This means that different gene pairs are passed on to offspring separately from one another, allowing for various combinations of traits. Gregor Mendel discovered this law, along with the law of segregation and the law of dominance, through his experiments with pea plants. The law of segregation (choice A) refers to how alleles of a gene separate during gamete formation, while the law of dominance (choice B) states that one allele can mask the presence of another in a heterozygous individual. The 'law of predictive traits' (choice D) is not a recognized Mendelian law and does not accurately describe the principles of genetic inheritance.
What describes a cell's reaction to being placed in a hypertonic solution?
- A. The cell will shrink as water is pulled out of the cell to equalize the concentrations inside and outside of the cell.
- B. The cell will swell as water is pulled into the cell to equalize the concentrations inside and outside of the cell.
- C. The cell will remain the same size since the concentrations inside and outside the cell are equal to begin with.
- D. The pH inside the cell will drop in order to equalize the pH inside and outside the cell.
Correct Answer: A
Rationale: A cell placed in a hypertonic solution has a higher solute concentration outside the cell compared to inside. This creates a concentration gradient that causes water to move out of the cell through osmosis to equalize the concentrations on both sides. As a result, the cell will shrink or undergo plasmolysis, as water is pulled out of the cell. Choice B is incorrect because a hypertonic solution causes water to move out of the cell, leading to shrinkage rather than swelling. Choice C is incorrect as a hypertonic solution results in a concentration gradient that leads to water leaving the cell, causing it to shrink. Choice D is incorrect because pH is not directly affected by being placed in a hypertonic solution; the change in solute concentration primarily impacts water movement.
Which of the following describes a situation in which research results are consistent with every subsequent experiment, but the test used in the experiment does not measure what it claims to measure?
- A. reliable, but not valid
- B. valid, but not reliable
- C. neither reliable nor valid
- D. both reliable and valid
Correct Answer: A
Rationale: The correct answer is A, 'reliable, but not valid.' In this scenario, the research results are consistent in every subsequent experiment, indicating reliability. However, the test used does not measure what it claims to measure, leading to a lack of validity in the results. Choice B, 'valid, but not reliable,' would imply that the test consistently measures what it claims but the results are not consistent, which is not the case here. Choice C, 'neither reliable nor valid,' would suggest that the results are neither consistent nor relevant, which does not align with the provided scenario. Choice D, 'both reliable and valid,' would mean that the results are consistent and measure what they claim to measure, which contradicts the situation described in the question.
Which of the following are the blood vessels that transport blood away from the heart?
- A. arteries
- B. capillaries
- C. venules
- D. veins
Correct Answer: A
Rationale: Arteries are blood vessels that carry oxygen-rich blood away from the heart to various parts of the body. Therefore, they are the vessels that transport blood away from the heart. Veins, on the other hand, transport blood back to the heart. Capillaries are tiny blood vessels where the exchange of nutrients and waste products occurs between blood and tissues, not vessels that transport blood to the heart. Venules are small veins that collect blood from capillaries and connect them to larger veins, rather than transport blood to the heart.