rna is made from dna through a process called

HESI A2

Biology HESI A2 Practice Exam

1. RNA is made from DNA through a process called ___________.

A. transcription
B. synthesis
C. translation
D. replication

Correct answer: A

Rationale: RNA is made from DNA through a process called transcription. During transcription, an enzyme called RNA polymerase reads the DNA template and synthesizes a complementary RNA molecule. This process is essential for gene expression and allows the information encoded in DNA to be converted into functional RNA molecules. Choice B, 'synthesis,' is incorrect as it is a general term and does not specifically describe the process of RNA formation from DNA. Choice C, 'translation,' is incorrect as it refers to the process where the mRNA is used to assemble amino acids during protein synthesis, not the conversion of DNA to RNA. Choice D, 'replication,' is incorrect as it is the process of making an identical copy of DNA, not converting DNA into RNA.

2. Why is polarity the most important characteristic of water?

A. the results of the polarity are hydrogen bonding, a high specific heat value, and its versatile solvent properties
B. the results of the polarity are covalent bonding, a low specific heat value, and its versatile solvent properties
C. the results of the polarity are ionic bonding, a high specific heat value, and its versatile solvent properties
D. the results of the polarity are hydrogen bonding, a low specific heat value, and its versatile solvent properties

Correct answer: A

Rationale: Polarity is the most important characteristic of water because it results in hydrogen bonding, a high specific heat value, and its versatile solvent properties. These unique properties enable water to form hydrogen bonds with other substances, resist temperature changes, and dissolve a wide variety of solutes, making it essential for life processes. Choice B is incorrect because water exhibits hydrogen bonding, not covalent bonding. Choice C is incorrect as water does not form ionic bonds. Choice D is incorrect because water has a high, not low, specific heat value, which is vital for its role in temperature regulation.

3. Which of the following is not a function of the skeletal system?

A. Providing the shape and form of our bodies
B. Supporting and protecting the body
C. Producing blood
D. Storing vitamins

Correct answer: C

Rationale: Producing blood is not a function of the skeletal system. Blood production primarily occurs in the bone marrow, which is found within the bones. The skeletal system provides the shape and form of our bodies, supports and protects the body, and stores minerals like calcium and phosphorus for various functions. Storing vitamins is not a primary function of the skeletal system, although some vitamins may play a role in bone health.

4. What is the role of tRNA during protein synthesis?

A. Carries amino acids to the ribosome
B. Links nucleotides together
C. Copies DNA sequences
D. Replicates genetic material

Correct answer: A

Rationale: During protein synthesis, tRNA plays the crucial role of carrying amino acids to the ribosome. This process ensures that the correct amino acids are brought to the ribosome according to the mRNA sequence. Choice B, linking nucleotides together, refers to the role of RNA polymerase in transcription, not tRNA. Choice C, copying DNA sequences, is the function of DNA polymerase during DNA replication, while choice D, replicating genetic material, is an overarching function of DNA replication, not specific to tRNA's role in protein synthesis.

5. Anaerobic respiration happens in _ because _ .

A. Animals; they need energy
B. Plants; they use sunlight
C. Bacteria; they live in environments with low oxygen
D. None of the above

Correct answer: C

Rationale: Anaerobic respiration happens in bacteria because they live in environments with low oxygen. Bacteria, unlike animals and plants, do not have easy access to oxygen for aerobic respiration and must find alternative ways to produce energy to survive. This makes anaerobic respiration essential for their metabolic processes. Choice A is incorrect because although animals need energy, they generally rely on aerobic respiration when oxygen is available. Choice B is incorrect because plants primarily perform photosynthesis using sunlight to produce energy. Choice D is incorrect as anaerobic respiration does occur in specific organisms like bacteria when oxygen is scarce.