synthesis of carbohydrates lipids and steroid hormones are functions of which of the following

HESI RN

Biology Practice Test

1. Which of the following is responsible for the synthesis of carbohydrates, lipids, and steroid hormones?

A. Smooth endoplasmic reticulum (ER)
B. Rough endoplasmic reticulum (ER)
C. Golgi apparatus
D. Ribosomes

Correct answer: A

Rationale: The smooth endoplasmic reticulum (ER) is the correct answer. It is responsible for the synthesis of lipids, including steroids, and also plays a role in carbohydrate metabolism. The rough endoplasmic reticulum (ER) is involved in protein synthesis and processing, not lipid or carbohydrate synthesis. The Golgi apparatus is responsible for modifying, sorting, and packaging of proteins and lipids, but not for their synthesis. Ribosomes are the cellular organelles responsible for protein synthesis, not lipid or carbohydrate synthesis.

2. Which of the following molecules acts as the genetic code's messenger?

A. RNA
B. Proteins
C. DNA
D. Carbohydrates

Correct answer: A

Rationale: The correct answer is RNA. RNA, particularly mRNA, serves as the messenger that carries genetic information from DNA to the ribosome, where proteins are synthesized. Proteins (choice B) are not the genetic code's messenger; they are synthesized based on the information carried by RNA. DNA (choice C) stores the genetic information but does not directly act as the messenger. Carbohydrates (choice D) are not involved in transmitting genetic information.

3. What is located on the rough endoplasmic reticulum?

A. Microvilli
B. Mitochondria
C. Lysosomes
D. Ribosomes

Correct answer: D

Rationale: The rough endoplasmic reticulum is studded with ribosomes, not microvilli, mitochondria, or lysosomes. Ribosomes are responsible for protein synthesis, making them an essential component of the rough endoplasmic reticulum.

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. What is the primary method of asexual reproduction used by most bacteria?

A. Meiosis
B. Mitosis
C. Binary fission
D. Interphase

Correct answer: C

Rationale: The correct answer is C: Binary fission. This is the main process through which most bacteria reproduce asexually. During binary fission, a single cell divides into two identical cells, each containing a copy of the genetic material. Choices A and B, meiosis and mitosis, are processes involved in sexual reproduction and are not used by bacteria for asexual reproduction. Choice D, interphase, is a stage of the cell cycle where the cell prepares for division and is not a method of reproduction.