which cell structure is responsible for efficiently packaging dna into a small volume to fit into the nucleus of a cell and protect the dna structure

HESI RN

Biology Test

1. Which cell structure is responsible for efficiently packaging DNA into a small volume to fit into the nucleus of a cell and protect the DNA structure and sequence?

A. Golgi apparatus
B. Chromatin
C. Smooth endoplasmic reticulum
D. Mitochondria

Correct answer: B

Rationale: The correct answer is B: Chromatin. Chromatin is responsible for packaging DNA into a more compact, dense shape to fit into the nucleus of a cell. This compact packaging helps protect the DNA structure and regulate gene expression. The Golgi apparatus is involved in modifying, sorting, and packaging proteins. The smooth endoplasmic reticulum is involved in lipid metabolism and detoxification. Mitochondria are known as the powerhouse of the cell, producing energy in the form of ATP.

2. During which stage of photosynthesis is solar energy converted to chemical energy?

A. During phosphate synthesis
B. During light reactions
C. During the Krebs cycle
D. During the Calvin cycle

Correct answer: B

Rationale: The correct answer is B, during the light reactions. During the light reactions of photosynthesis, solar energy is absorbed by chlorophyll and converted into chemical energy in the form of ATP and NADPH. Choice A is incorrect as phosphate synthesis does not involve the conversion of solar energy. Choice C, the Krebs cycle, is a part of cellular respiration, not photosynthesis. Choice D, the Calvin cycle, is responsible for fixing carbon dioxide into carbohydrates and does not involve the direct conversion of solar energy to chemical energy.

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

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

Correct answer: C

Rationale: The correct answer is C: Lysosomes. Lysosomes contain enzymes that break down waste materials and cellular debris within the cell, making them the cell's digestion center. Choice A, Chloroplasts, are responsible for photosynthesis. Choice B, Mitochondria, are the powerhouse of the cell, generating energy. Choice D, Ribosomes, are involved in protein synthesis. Therefore, Lysosomes are specifically known for their role in digestion within the cell.

4. What is the science of biological classification commonly called?

A. Taxonomy
B. Physiology
C. Botany
D. Zoology

Correct answer: A

Rationale: Taxonomy is the science of naming, defining, and classifying groups of biological organisms based on shared characteristics. Physiology (choice B) is the study of the functions and processes of living organisms, not classification. Botany (choice C) is the study of plants, while Zoology (choice D) is the study of animals. Therefore, the correct answer is Taxonomy (choice A).

5. Which of the following provides support and shape to the cell?

A. Microtubules
B. Microfilaments
C. Cilia
D. Microvilli

Correct answer: A

Rationale: Microtubules are fundamental components of the cytoskeleton in a cell, playing a crucial role in providing structural support and maintaining the cell's shape. They are composed of tubulin protein subunits and are involved in various cellular processes like cell division, intracellular transport, and cell motility. Microfilaments, on the other hand, are involved in cell movement and maintaining cell shape but are not primarily responsible for supporting the cell's overall structure. Cilia and microvilli are cellular projections that aid in movement and absorption, respectively, but they do not play a significant role in providing structural support to the cell.