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

HESI RN

Biology Test

1. 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.

2. Water is held together by which of the following bonds?

A. Electrostatic attraction
B. Van der Waals forces
C. Hydrogen
D. Oxygen

Correct answer: C

Rationale: Water molecules are held together by hydrogen bonds, which are weak bonds formed between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another. Choice A, electrostatic attraction, is a general term for the attraction between opposite charges but does not specifically describe the bonds in water. Choice B, Van der Waals forces, are weak intermolecular forces that arise from temporary fluctuations in electron distribution, not the primary bonds in water. Choice D, oxygen, is incorrect as oxygen is part of the water molecule but not the bond holding water molecules together.

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. Who discovered the basic principles of genetics using garden peas?

A. Curie
B. Mendel
C. Hawking
D. Galileo

Correct answer: B

Rationale: The correct answer is B, Mendel. Gregor Mendel is known as the father of genetics for his groundbreaking work with pea plants. He discovered the basic principles of heredity through his experiments, establishing the foundation of modern genetics. Choice A, Curie, is incorrect as Marie Curie was a physicist and chemist known for her pioneering research on radioactivity. Choice C, Hawking, is incorrect as Stephen Hawking was a theoretical physicist known for his work on black holes and cosmology. Choice D, Galileo, is incorrect as Galileo Galilei was an astronomer and physicist renowned for his contributions to the scientific revolution, particularly in astronomy.

5. Which of the following is often referred to as the powerhouse of the cell?

A. Nucleus
B. Chromatin
C. Mitochondria
D. Ribosomes

Correct answer: C

Rationale: Mitochondria are known as the powerhouse of the cell because they generate most of the cell's supply of ATP, which is the energy currency used for various cellular processes. The nucleus (Choice A) is the control center of the cell, housing genetic material. Chromatin (Choice B) is a complex of DNA and proteins within the nucleus. Ribosomes (Choice D) are responsible for protein synthesis and not the primary energy production in the cell.