HESI A2
Biology HESI A2 Practice Test Questions
Question 1 of 5
Which of the following describes the situation where one allele takes a different form from another in a gene?
Correct Answer: B
Rationale: Heterozygous is the term used to describe the genotype of an individual with two different alleles for a specific gene. In this case, one allele takes a different form from another, resulting in genetic diversity and variation in trait expression. The other choices are incorrect: 'phenotype' refers to the observable traits of an organism, 'homolog' typically refers to chromosomes that are similar in structure, and 'homozygous' describes the genotype where both alleles for a gene are the same.
Question 2 of 5
Select the cell parts that are present in plant cells but not animal cells (there may be more than one answer):
Correct Answer: B
Rationale: Plant cells have a cell wall (
B) which provides structural support and protection for the cell, a feature that is not present in animal cells. The cell membrane (
A) is found in both plant and animal cells. Ribosomes (
C) are present in both types of cells and are responsible for protein synthesis. Chloroplasts (
D) are unique to plant cells and are responsible for carrying out photosynthesis.
Therefore, the correct answers are B and D because the cell wall and chloroplast are specific to plant cells, while the cell membrane and ribosomes are found in both plant and animal cells.
Question 3 of 5
Which two bases are purines?
Correct Answer: A
Rationale: Adenine (
A) and guanine (G) are the two bases that are purines. Purines are characterized by a double-ring structure containing two carbon rings, distinguishing them from pyrimidines. Adenine and guanine are purines because they possess this unique double-ring structure.
Therefore, choices A and D, adenine and guanine, respectively, are the correct answers.
Choices B and C, cytosine and thymine, are pyrimidines and do not exhibit the double-ring structure characteristic of purines.
Question 4 of 5
72 chromosomes undergo meiosis. How many chromosomes will be in each gamete?
Correct Answer: A
Rationale: During meiosis, the number of chromosomes is halved in each gamete. Since 72 chromosomes undergo meiosis, each gamete will contain half of that number, which is 36 chromosomes.
Therefore, the correct answer is 18 chromosomes in each gamete.
Choice B (36 chromosomes) is incorrect because it represents the total number of chromosomes that undergo meiosis, not the number in each gamete.
Choice C (72 chromosomes) is incorrect as it represents the initial number of chromosomes, not the number in each gamete after meiosis.
Choice D (144 chromosomes) is incorrect as it doubles the initial number of chromosomes, which is not the outcome of meiosis.
Question 5 of 5
Which of the following is not true about antibiotics?
Correct Answer: C
Rationale: The correct answer is C. Antibiotics do not cause more bacteria to grow. They work by interfering with the bacteria's ability to survive, affecting how they multiply, or killing the bacteria cells. Antibiotics specifically target bacteria, so they do not promote the growth of more bacteria.
Choices A, B, and D are true statements about antibiotics as they accurately describe how antibiotics work and their specific action on bacteria.