dna and rna are both subunits of which biological molecule

HESI RN

Biology Practice Test

1. 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.

2. Which of the following 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 versions of a gene that can exist at a specific locus on a chromosome. This term specifically refers to the different forms of a gene that can exist. Choices B, C, and D are incorrect because they do not represent alternative versions of a gene. Binary fission is a form of asexual reproduction in single-celled organisms, while heterozygous and homozygous refer to the genetic makeup of an individual rather than alternative versions of a gene.

3. Which of the following organelles is known as the cell's transportation center?

A. Golgi apparatus
B. Endoplasmic reticulum
C. Mitochondria
D. Lysosomes

Correct answer: B

Rationale: The correct answer is B, Endoplasmic reticulum. The endoplasmic reticulum is involved in the synthesis and transport of proteins and lipids within the cell. The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids for transport. Mitochondria are known as the powerhouse of the cell, producing energy in the form of ATP. Lysosomes are involved in the digestion and recycling of cellular waste.

4. Where can ribosomes be found inside a cell?

A. Attached to the endoplasmic reticulum (ER) and in the cytoplasm
B. Within the cellular membrane
C. Attached to the Golgi apparatus and in the cytoplasm
D. Within the nucleus

Correct answer: A

Rationale: Ribosomes can be found attached to the endoplasmic reticulum (ER) or free-floating in the cytoplasm. The correct answer is A because ribosomes are responsible for synthesizing proteins and are commonly found on the ER or in the cytoplasm. Choice B is incorrect because ribosomes are not typically located within the cellular membrane. Choice C is incorrect as ribosomes are not attached to the Golgi apparatus; instead, they are involved in protein synthesis. Choice D is incorrect as ribosomes are not found within the nucleus but rather in the cytoplasm or attached to the ER.

5. 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.