Biology Test Biology Cell Structure & Function 2 — Questions and Answers
Question 1: Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?
- Smooth ER
- Golgi apparatus (Correct answer)
- Lysosome
- Peroxisome
Correct answer: Golgi apparatus
The Golgi apparatus receives proteins from the ER, modifies them, and packages them into vesicles for transport or secretion.
Question 2: What is the primary function of lysosomes?
- Synthesizing proteins
- Producing ATP
- Digesting cellular waste and foreign material (Correct answer)
- Storing genetic information
Correct answer: Digesting cellular waste and foreign material
Lysosomes contain hydrolytic enzymes that break down macromolecules, old organelles, and pathogens in a process called autophagy or phagocytosis.
Question 3: Which cytoskeletal component is primarily responsible for cell shape and resisting compression?
- Microfilaments
- Intermediate filaments
- Microtubules (Correct answer)
- Motor proteins
Correct answer: Microtubules
Microtubules are hollow tubes made of tubulin that provide structural support, maintain cell shape, and form tracks for organelle transport.
Question 4: What distinguishes smooth endoplasmic reticulum from rough endoplasmic reticulum?
- Smooth ER contains DNA; rough ER does not
- Smooth ER lacks ribosomes; rough ER has ribosomes on its surface (Correct answer)
- Smooth ER produces ATP; rough ER produces lipids
- Smooth ER is found only in plant cells
Correct answer: Smooth ER lacks ribosomes; rough ER has ribosomes on its surface
Rough ER has ribosomes attached to its cytoplasmic surface for protein synthesis, while smooth ER lacks ribosomes and is involved in lipid synthesis and detoxification.
Question 5: In which part of a eukaryotic cell does translation occur?
- Nucleus
- Mitochondria only
- Ribosomes in the cytoplasm and on rough ER (Correct answer)
- Golgi apparatus
Correct answer: Ribosomes in the cytoplasm and on rough ER
Translation (protein synthesis) occurs at ribosomes, which can be free in the cytoplasm or attached to the rough endoplasmic reticulum.
Question 6: What is the role of the centrosome in animal cells?
- Synthesizing lipids for the plasma membrane
- Organizing the mitotic spindle during cell division (Correct answer)
- Storing calcium ions for muscle contraction
- Producing ribosomes for protein synthesis
Correct answer: Organizing the mitotic spindle during cell division
The centrosome, containing a pair of centrioles, is the main microtubule-organizing center and nucleates spindle fibers during mitosis.
Question 7: Which feature of the plasma membrane allows it to be selectively permeable?
- Its rigid cellulose framework
- The phospholipid bilayer with embedded proteins (Correct answer)
- The presence of a thick glycocalyx only
- A solid cholesterol core
Correct answer: The phospholipid bilayer with embedded proteins
The phospholipid bilayer's hydrophobic core blocks most polar molecules, while embedded transport proteins selectively allow specific substances to cross.
Biology Test Biology Cell Structure & Function 2
Which organelle is responsible for modifying, sorting, and packaging proteins for secretion?