the correct answer is d heterozygous traits contain one dominant and one recessive form of the gene which of the following is true of homozygous trait

HESI A2

Biology HESI A2 Practice Test

1. Which of the following is true of homozygous traits?

A. They are haploid
B. They are denoted AA
C. They are denoted aa
D. They are denoted Aa

Correct answer: B

Rationale: Homozygous traits have two identical forms of the gene, either both dominant (AA) or both recessive (aa). Therefore, choices B and C are true for homozygous traits. Choice A is incorrect because being haploid refers to having a single set of chromosomes, not necessarily homozygous traits. Choice D is incorrect as homozygous traits have identical alleles, so they are not denoted as Aa.

2. How are lipids different from other organic molecules?

A. They are indivisible.
B. They are not water soluble.
C. They contain zinc.
D. They form long proteins.

Correct answer: B

Rationale: The correct answer is B: 'They are not water soluble.' Lipids are not water-soluble, which distinguishes them from other organic molecules. Choice A is incorrect because lipids are not indivisible; they can be broken down into fatty acids and glycerol. Choice C is incorrect as lipids do not necessarily contain zinc; they are a diverse group of molecules. Choice D is incorrect because lipids do not form long proteins; proteins are made up of amino acids, not lipids.

3. Patient A, who weighs 68 kilograms, steps onto a scale 20 times. The scale consistently weighs Patient A as 75 kilograms. What is true of the measurement?

A. It is valid, but not reliable.
B. It is reliable, but not valid.
C. It is both valid and reliable.
D. It is neither reliable nor valid.

Correct answer: B

Rationale: The correct answer is B: 'It is reliable, but not valid.' The measurement is reliable because it consistently provides the same result (75 kg). However, it is not valid because it does not accurately reflect the true weight of Patient A (68 kg). Choice A is incorrect because if the scale consistently shows the same weight (75 kg), it is reliable. Choice C is incorrect because although the scale is consistent, the measurement does not reflect the true weight, making it not valid. Choice D is incorrect as the measurement is reliable but lacks validity.

4. During which phase of cell division do the chromosomes replicate?

A. Prophase
B. Interphase
C. Anaphase
D. Telophase

Correct answer: B

Rationale: Chromosomes replicate during the interphase of the cell cycle. Interphase is the phase where the cell prepares for division by undergoing various activities such as growth, DNA replication, and protein synthesis. During DNA replication in interphase, each chromosome in the cell is duplicated to form two sister chromatids, which are then separated during cell division. Prophase is the phase where the chromosomes condense, and the nuclear envelope breaks down. Anaphase is the phase where sister chromatids are pulled apart towards opposite poles of the cell. Telophase is the phase where the nuclear envelope reforms, and chromosomes begin to decondense.

5. How should a researcher test the hypothesis that a particular species of bird vocalizes most in the hours around dawn?

A. Observe a flock of the birds in captivity and record them at two-hour intervals from predawn until sunset for a month.
B. Observe a flock of the birds in the wild and record them at one-hour intervals from predawn until sunset in several seasons.
C. Observe a flock of the birds in the wild and record them in predawn and postdawn hours every day for six months.
D. Observe a flock of the birds in the wild, record them at one-hour intervals for a month, and compare that recording to recordings of other species.

Correct answer: C

Rationale: Observing a flock of the birds in the wild and recording them in predawn and postdawn hours every day for six months would be the best way to test the hypothesis that a particular species of bird vocalizes most in the hours around dawn. This method allows for consistent monitoring of the birds during specific times of interest over an extended period, providing a comprehensive dataset to accurately analyze the vocalization patterns. Options A and B do not focus specifically on dawn hours, making them less suitable for testing the hypothesis. Option D introduces a comparison with other species, which is unnecessary and distracts from the main objective of studying the vocalization pattern of the particular bird species around dawn.