which of the following are considered the most important molecules in biology

HESI A2

HESI A2 Practice Test Biology

1. Which of the following are considered the most important molecules in biology?

A. Carbohydrates, lipids, protein, and nucleic acids
B. Carbohydrates, lipids, protein, and calcium
C. Carbohydrates, lipids, protein, and sulfur
D. Carbohydrates, lipids, protein, and iron

Correct answer: A

Rationale: The correct answer is A: Carbohydrates, lipids, protein, and nucleic acids are considered the most important molecules in biology. Carbohydrates are essential for providing energy, lipids for storing energy and forming cell membranes, proteins for various structural and functional roles, and nucleic acids (DNA and RNA) for storing genetic information. Choices B, C, and D are incorrect because while carbohydrates, lipids, and proteins are crucial biomolecules, calcium, sulfur, and iron are not considered among the most important molecules in biology.

2. What type of cell is an animal cell?

A. Prokaryotic
B. Eukaryotic
C. Plant Cell
D. Bacterial Cell

Correct answer: B

Rationale: The correct answer is B, eukaryotic. Animal cells are classified as eukaryotic cells because they contain membrane-bound organelles such as the nucleus, mitochondria, and endoplasmic reticulum. Choice A, prokaryotic, is incorrect as prokaryotic cells lack membrane-bound organelles. Choice C, Plant Cell, is incorrect as the question specifically asks about animal cells. Choice D, Bacterial Cell, is incorrect as bacteria are prokaryotic cells.

3. What is the most important component of the cell, contributing to protection, communication, and the passage of substances?

A. Cytoplasm
B. Cell Membrane
C. Cytoskeleton
D. Vacuole

Correct answer: B

Rationale: The cell membrane is the correct answer. It is the most important component of the cell as it provides protection, facilitates communication, and regulates the passage of substances in and out of the cell. The cytoplasm (Choice A) is the gel-like substance within the cell that holds organelles, but it is not primarily responsible for the functions mentioned in the question. The cytoskeleton (Choice C) provides structural support to the cell but is not directly involved in protection, communication, or substance passage. Vacuoles (Choice D) are responsible for storage and maintaining turgor pressure but do not play a primary role in the functions specified in the question.

4. Which molecule is primarily responsible for storing energy in cells?

A. Glucose
B. ATP
C. Fatty acids
D. Starch

Correct answer: B

Rationale: ATP is the correct answer because it is the molecule responsible for storing and providing energy in cells. Glucose is a source of energy but not primarily for storage. Fatty acids are more involved in energy production through oxidation. Starch is a polysaccharide used for energy storage in plants.

5. Which of the following is not true about antibiotics?

A. They can interfere with the bacteria's ability to survive
B. They can affect how bacteria multiply
C. They can cause more bacteria to grow
D. They only work on bacteria

Correct answer: C

Rationale: The correct answer is C. Antibiotics do not cause more bacteria to grow. They work by interfering with the bacteria's ability to survive, affecting how they multiply, or killing the bacteria cells. Antibiotics specifically target bacteria, so they do not promote the growth of more bacteria. Choices A, B, and D are true statements about antibiotics as they accurately describe how antibiotics work and their specific action on bacteria.