All Free Biology MCQs with Answers

• A. ER with ribosome and ER without ribosome
• B. ER with cisternae and ER without cisternae
• C. ER with enzymes and ER without enzymes
• D. Rough endoplasmic reticulum and sarcoplasmic reticulum

Explanation: The endoplasmic reticulum (ER) can be categorized into two primary forms based on the presence of ribosomes.

• A. Trans face (maturation face)
• B. Cis face (forming face)
• C. Convex face
• D. Vesicle release face

Explanation: The Golgi apparatus consists of a series of flattened membrane-bound sacs known as cisternae, with distinct cis and trans faces.

• A. Cis face (forming face)
• B. Inner face
• C. Trans face
• D. Distal face

Explanation: Vesicles from the Smooth Endoplasmic Reticulum (SER) are referred to as 'blebs' in the context of their budding and transport.

• A. Smooth Endoplasmic Reticulum (SER)
• B. Rough Endoplasmic Reticulum (RER)
• C. Golgi apparatus
• D. Lysosomes

Explanation: The correct answer is the Golgi apparatus, which modifies and packages proteins and enzymes into vesicles for secretion, forming granules…

• A. Smooth Endoplasmic Reticulum (SER)
• B. Rough Endoplasmic Reticulum (RER)
• C. Golgi apparatus
• D. Mitochondria

Explanation: The correct answer is the Golgi apparatus, which is crucial for processing, modifying, and packaging proteins and lipids.

• A. Vary slightly
• B. Do not change
• C. Vary widely
• D. Are identical

Explanation: The correct answer is that the number, shape, and internal structure of mitochondria vary widely.

• A. Freely scattered in cytoplasm and attached with SER
• B. Freely scattered in cytoplasm and attached with RER
• C. Freely scattered in nucleoplasm and attached with RER
• D. Freely scattered in nucleoplasm and attached with SER

Explanation: Ribosomes are critical for protein synthesis in eukaryotic cells. They are found in two main locations: freely scattered in the cytoplasm…

• A. The larger subunit sediments at 60S while the smaller subunit sediments at 40S
• B. The larger subunit sediments at 50S, while the smaller subunit sediments at 30S
• C. The larger subunit sediments at 60S, while the smaller subunit sediments at 30S
• D. The larger subunit sediments at 50S, while the smaller subunit sediments at 40S

Explanation: The correct answer is that the larger subunit of eukaryotic ribosomes sediments at 60S, and the smaller subunit sediments at 40S.

• A. Position in the cell
• B. Composition
• C. Length
• D. Diameter

Explanation: The correct answer is that intermediate filaments are named for their diameter.

• A. Nucleus & mitochondria
• B. Golgi apparatus & Endoplasmic Reticulum (ER)
• C. Chloroplast & mitochondria
• D. Cilia

Explanation: The endosymbiotic hypothesis suggests that mitochondria and chloroplasts originated from free-living bacteria that established a symbiotic…

• A. Endoplasmic Reticulum (ER)
• B. Golgi Apparatus
• C. Centrioles
• D. Lysosomes

Explanation: The nuclear outer membrane is directly continuous with the endoplasmic reticulum (ER).

• A. Golgi apparatus
• B. Endoplasmic reticulum
• C. Ribosome
• D. Lysosome

Explanation: The correct answer is the Golgi apparatus, which is crucial for processing and packaging proteins and enzymes into vesicles for secretion.

• A. Endoplasmic Reticulum (ER)
• B. Mitochondria
• C. Golgi Apparatus (Golgi bodies)
• D. Nucleus

Explanation: The phragmoplast is a plant cell structure that appears during late cytokinesis.

• A. Endoplasmic Reticulum: Storage of carbohydrates
• B. Golgi Apparatus: Processing and packaging proteins
• C. Mitochondria: Energy production through ATP synthesis
• D. Ribosomes: Protein synthesis

Explanation: The correct answer is the endoplasmic reticulum (ER) paired with the storage of carbohydrates.

• A. Increased number of Golgi apparatus
• B. Increased amounts of rough endoplasmic reticulum (RER)
• C. Both A and B
• D. None

Explanation: Exocrine cells have a secretory function that involves the synthesis and processing of proteins and other molecules for export.

• A. Primary wall
• B. Secondary wall
• C. Middle lamella
• D. All of the above

Explanation: The primary wall is crucial for maintaining cell shape and integrity. While the secondary wall also contains cellulose, the primary wall…

• A. Synthesis of steroid hormones from cholesterol.
• B. Synthesis of phospholipids for plasma membrane.
• C. Synthesis of membrane proteins.
• D. Synthesis of steroid hormones.

Explanation: The Smooth Endoplasmic Reticulum (SER) is primarily associated with lipid synthesis, including steroid hormones and phospholipids, and…

• A. Cytosol
• B. Cisternae
• C. Lysosomes
• D. Cristae

Explanation: The correct answer is cisternae. Cisternae are the structural components of the endoplasmic reticulum, which are either spherical or…

• A. Symplast
• B. Nucleoplasm
• C. Rough Endoplasmic Reticulum (RER)
• D. Smooth Endoplasmic Reticulum (SER)

Explanation: The Smooth Endoplasmic Reticulum (SER) is the correct answer because it is specifically involved in the synthesis of lipids such as…

• A. A layer present between cell wall and membrane of bacteria
• B. Cell wall of bacteria
• C. Bacterial cell engineered to possess N-glycosylated proteins
• D. A layer surrounding the cell wall of bacteria

Explanation: The correct answer is Option D: A layer surrounding the cell wall of bacteria.