HESI RN
Biology Practice Test
1. In the hierarchical organizational system, which of these is the most restrictive category?
- A. Genus
- B. Class
- C. Kingdom
- D. Species
Correct answer: D
Rationale: In the biological classification hierarchy, species is the most specific level, defining individual organisms that can interbreed. While genus, class, and kingdom are also categories in the hierarchy, they are broader and encompass a wider range of organisms compared to species. Genus groups together similar species, class groups similar orders, and kingdom is the broadest category grouping together similar phyla.
2. Which of the following is not one of the four nitrogenous bases that make up the DNA structure?
- A. Adenine
- B. Guanine
- C. Uracil
- D. Thymine
Correct answer: C
Rationale: The correct answer is C: Uracil. Uracil is found in RNA, not DNA. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine. Choice A, Adenine, is a nitrogenous base in DNA. Choice B, Guanine, is another nitrogenous base in DNA. Choice D, Thymine, is also one of the four nitrogenous bases in DNA. Therefore, the correct answer is Uracil (Choice C).
3. Which of the following molecules contains the code required for replication?
- A. Deoxyribonucleic acid (DNA)
- B. Transfer RNA (tRNA)
- C. Messenger RNA (mRNA)
- D. Ribonucleic acid (RNA)
Correct answer: A
Rationale: The correct answer is A: Deoxyribonucleic acid (DNA). DNA contains the genetic information essential for replication, ensuring the accurate transmission of genetic material from one generation to the next. Choice B, Transfer RNA (tRNA), is involved in protein synthesis, not replication. Choice C, Messenger RNA (mRNA), carries genetic information from DNA to the ribosome but does not contain the code for replication. Choice D, Ribonucleic acid (RNA), is a broader category that includes both mRNA and tRNA, but the specific molecule containing the code required for replication is DNA.
4. What characteristic of water allows for hydrogen bonding between molecules?
- A. Its covalent bonds
- B. Its cohesive properties
- C. Its high specific heat
- D. Its polar nature
Correct answer: D
Rationale: The correct answer is D: Its polar nature. Water is a polar molecule with a partial positive charge on hydrogen atoms and a partial negative charge on oxygen atoms. This polarity allows water molecules to form hydrogen bonds with each other. Choice A, covalent bonds, is incorrect because while water indeed has covalent bonds, they do not directly enable hydrogen bonding. Choice B, cohesive properties, is incorrect as cohesion refers to water's ability to stick to other substances, not the specific characteristic that allows for hydrogen bonding. Choice C, high specific heat, is also incorrect as it refers to water's ability to resist changes in temperature, not its property that leads to hydrogen bonding.
5. What percentage of the offspring of the parents is predicted to have a cleft chin?
- A. 25%
- B. 50%
- C. 0%
- D. 75%
Correct answer: A
Rationale: When one parent carries the recessive gene for a cleft chin and the other does not, there is a 25% chance of the offspring inheriting the cleft chin. This is due to the fact that the trait follows a simple Mendelian inheritance pattern, where the offspring would need to inherit the recessive gene from both parents to express the trait. Therefore, 25% of the offspring are predicted to have a cleft chin. Choices B, C, and D are incorrect because the likelihood of inheriting a cleft chin in this specific scenario is 25%, not 50%, 0%, or 75%.
Similar Questions
Access More Features
HESI RN Basic
$69.99/ 30 days
- 5,000 Questions with answers
- All HESI courses Coverage
- 30 days access
HESI RN Premium
$149.99/ 90 days
- 5,000 Questions with answers
- All HESI courses Coverage
- 30 days access