Question 21:
Which type of cells are characterized by the absence of a true nucleus?
A) Eukaryotic cells
B) Prokaryotic cells
C) Stem cells
D) Muscle cells
Answer: B) Prokaryotic cells
Explanation: Prokaryotic cells lack a membrane-bound nucleus; their genetic material is located in the nucleoid region.
Question 22:
What structure is involved in the synthesis of ATP in the mitochondria?
A) Outer membrane
B) Inner membrane
C) Matrix
D) Cristae
Answer: D) Cristae
Explanation: The cristae are the inner folds of the mitochondrial membrane where the electron transport chain occurs, leading to ATP production.
Question 23:
What type of cell junctions prevent the passage of materials between cells?
A) Desmosomes
B) Tight junctions
C) Gap junctions
D) Anchoring junctions
Answer: B) Tight junctions
Explanation: Tight junctions create a seal between adjacent cells, preventing the leakage of materials between them.
Question 24:
Which of the following structures is essential for cell division in animal cells?
A) Cell wall
B) Centrioles
C) Chloroplasts
D) Nucleus
Answer: B) Centrioles
Explanation: Centrioles are involved in the organization of the mitotic spindle during cell division in animal cells.
Question 25:
What is the primary function of the rough endoplasmic reticulum (RER)?
A) Lipid synthesis
B) Protein synthesis
C) Detoxification
D) Energy production
Answer: B) Protein synthesis
Explanation: The rough endoplasmic reticulum is studded with ribosomes and is primarily involved in the synthesis of proteins that are either secreted or incorporated into membranes.
Question 26:
Which of the following is a characteristic feature of plant cells?
A) Large central vacuole
B) Centrioles
C) Lysosomes
D) Mitochondria
Answer: A) Large central vacuole
Explanation: Plant cells typically contain a large central vacuole that stores water, nutrients, and waste products, and helps maintain turgor pressure.
Question 27:
What is the primary role of the cell wall in plant cells?
A) Energy production
B) Protein synthesis
C) Structural support and protection
D) Photosynthesis
Answer: C) Structural support and protection
Explanation: The cell wall provides rigidity and protection to plant cells, helping to maintain their shape and prevent excessive water loss.
Question 28:
Which of the following best describes the fluid mosaic model of the cell membrane?
A) A rigid structure composed of lipids and proteins
B) A dynamic structure with proteins floating in a lipid bilayer
C) A layer of carbohydrates surrounding a lipid bilayer
D) A static arrangement of phospholipids
Answer: B) A dynamic structure with proteins floating in a lipid bilayer
Explanation: The fluid mosaic model describes the cell membrane as a flexible structure where various proteins are embedded within a fluid phospholipid bilayer.
Question 29:
What is the primary function of vacuoles in plant cells?
A) Energy production
B) Storage of substances
C) Protein synthesis
D) Photosynthesis
Answer: B) Storage of substances
Explanation: Vacuoles are primarily responsible for storing water, nutrients, and waste products in plant cells, contributing to cell turgor.
Question 30:
Which organelle is involved in the synthesis of ribosomal RNA?
A) Nucleus
B) Ribosome
C) Golgi Apparatus
D) Endoplasmic Reticulum
Answer: A) Nucleus
Explanation: The nucleolus, located within the nucleus, is responsible for synthesizing ribosomal RNA (rRNA) and assembling ribosomes.
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