which of the following is a group of three rna nucleotides

HESI RN

Biology Practice Test

1. Which of the following is a group of three RNA nucleotides?

A. A stop codon
B. A codon
C. An anticodon
D. tRNA

Correct answer: B

Rationale: The correct answer is B - A codon. A codon is a sequence of three RNA nucleotides that specifies a particular amino acid or a stop signal during protein synthesis. Choice A, a stop codon, is a sequence of three nucleotides that signals the termination of protein synthesis. Choice C, an anticodon, is a group of three nucleotides found in tRNA that pairs with the complementary codon in mRNA. Choice D, tRNA, stands for transfer RNA, which is a type of RNA that carries amino acids to the ribosome during protein synthesis.

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 options is the term used to represent alternative versions of a gene?

A. Alleles
B. Binary fission
C. Heterozygous
D. Homozygous

Correct answer: A

Rationale: The correct answer is A: Alleles. Alleles are different forms of a gene that can exist at a specific locus on a chromosome. They represent variations in a gene's DNA sequence. Choices B, C, and D are incorrect. Binary fission is a form of asexual reproduction in single-celled organisms, while heterozygous and homozygous refer to different combinations of alleles in an individual, not the alternative versions of a gene.

4. What is the liquid found inside the cell?

A. Plasma membrane
B. Cilia
C. Cytoplasm
D. Cytosol

Correct answer: D

Rationale: The correct answer is D, Cytosol. Cytosol is the liquid component of the cytoplasm where various cellular processes occur. Choices A, B, and C are incorrect because the plasma membrane is the outer boundary of the cell, cilia are hair-like structures on the cell surface, and cytoplasm is the jelly-like substance that contains organelles within the cell, not the liquid inside the cell.

5. Which two items react during cellular respiration?

A. Glucose and water
B. Carbon dioxide and water
C. Carbon dioxide and oxygen
D. Glucose and oxygen

Correct answer: D

Rationale: The correct answer is D: Glucose and oxygen. During cellular respiration, glucose and oxygen react in the presence of enzymes to produce carbon dioxide, water, and energy in the form of ATP. Choice A (Glucose and water) is incorrect because water is a product of cellular respiration, not a reactant. Choice B (Carbon dioxide and water) is incorrect as carbon dioxide is produced during cellular respiration, not a reactant. Choice C (Carbon dioxide and oxygen) is incorrect because oxygen is a reactant in cellular respiration, not a product.