which of the following is not one of the four nitrogenous bases that make up the dna structure

HESI RN

Biology Practice Test

1. 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).

2. Which of the following options correctly lists biology's hierarchical organizational system?

A. Phylum, Kingdom, Class, Family, Order, Species, Genus
B. Kingdom, Phylum, Class, Order, Family, Genus, Species
C. Genus, Order, Kingdom, Class, Phylum, Species, Family
D. Class, Phylum, Kingdom, Genus, Order, Family, Species

Correct answer: B

Rationale: The correct hierarchical organizational system in biology is Kingdom, Phylum, Class, Order, Family, Genus, and Species. This follows the mnemonic 'King Phillip Came Over For Good Soup.' Choice A is incorrect as it does not follow the correct hierarchical order. Choice C is incorrect as it starts with Genus, which is more specific and should come after Family. Choice D is incorrect as it does not follow the correct hierarchical order.

3. Which of the following statements is most accurate regarding the transcription of DNA?

A. RNA uses reverse transcriptase to make mRNA
B. DNA uses mRNA to produce tRNA
C. RNA creates a duplicate copy of DNA
D. RNA copies DNA to produce mRNA

Correct answer: D

Rationale: The correct answer is D. During transcription, RNA copies DNA to produce mRNA, which carries the genetic information from DNA to the ribosomes for protein synthesis. Choice A is incorrect because reverse transcriptase is not involved in the transcription of DNA. Choice B is incorrect as DNA does not use mRNA to produce tRNA; tRNA is produced through a different process. Choice C is incorrect as RNA does not create a duplicate copy of DNA during transcription; it synthesizes mRNA by copying the DNA template.

4. Which of the following is not found in a prokaryotic cell?

A. Plasma membrane
B. Cytoplasm
C. Nucleus
D. Ribosomes

Correct answer: C

Rationale: The correct answer is C, 'Nucleus.' Prokaryotic cells do not have a defined nucleus, unlike eukaryotic cells. The plasma membrane, cytoplasm, and ribosomes are all components found in prokaryotic cells. The plasma membrane surrounds the cell and regulates what enters and exits, the cytoplasm is the gel-like substance that fills the cell, and ribosomes are responsible for protein synthesis.

5. Which of the following organelles is known as the cell's digestion center?

A. Chloroplasts
B. Mitochondria
C. Lysosomes
D. Ribosomes

Correct answer: C

Rationale: The correct answer is C: Lysosomes. Lysosomes contain enzymes that break down waste materials and cellular debris within the cell, making them the cell's digestion center. Choice A, Chloroplasts, are responsible for photosynthesis. Choice B, Mitochondria, are the powerhouse of the cell, generating energy. Choice D, Ribosomes, are involved in protein synthesis. Therefore, Lysosomes are specifically known for their role in digestion within the cell.