which of the following molecules contains the code that is required for replication

HESI RN

Biology Test

1. 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.

2. Protein synthesis begins with a process known as transcription. Where does this process occur?

A. In the cytoplasm
B. In the nuclear envelope
C. In the ribosome unit
D. In the nucleus

Correct answer: D

Rationale: The correct answer is D: In the nucleus. Transcription, the initial step of protein synthesis, takes place in the nucleus where DNA is transcribed into mRNA. This mRNA then leaves the nucleus and enters the cytoplasm where translation occurs on the ribosomes. Choices A, B, and C are incorrect because transcription specifically occurs in the nucleus, not in the cytoplasm, nuclear envelope, or ribosome unit.

3. During which stage of mitosis do the chromosomes gather on either side of the separating cell?

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

Correct answer: B

Rationale: The correct answer is B, Telophase. During telophase, the chromosomes gather at opposite poles of the cell as the nuclear envelopes start to form around them, indicating the end of cell division. Choices A, C, and D are incorrect because during metaphase, the chromosomes align in the middle of the cell; in anaphase, the chromosomes separate and move towards opposite poles; and in prophase, the chromosomes condense and the nuclear envelope breaks down, respectively.

4. DNA and RNA are both subunits of which biological molecule?

A. Nucleic acids
B. Proteins
C. Carbohydrates
D. Lipids

Correct answer: A

Rationale: The correct answer is A: Nucleic acids. DNA and RNA are both types of nucleic acids, which are fundamental biological molecules responsible for storing and transmitting genetic information. Choice B, Proteins, are not subunits of DNA and RNA but are composed of amino acids. Carbohydrates, choice C, are another type of biological molecule involved in energy storage and structural support, not subunits of DNA and RNA. Lipids, choice D, are a diverse group of molecules that include fats, oils, and steroids, but they are not subunits of DNA and RNA.

5. 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).