Endoplasmic Reticulum (ER) MCQs Quiz | Class 9
This quiz covers Unit II: Organization in the Living World for Class IX Science (Code 086). It focuses on the Endoplasmic Reticulum (ER), specifically its types (Rough vs Smooth), functions in transport and synthesis, and membrane biogenesis. Attempt these 10 MCQs to test your understanding, then submit to check your score and download the PDF answer sheet.
Endoplasmic Reticulum: Structure and Functions
The Endoplasmic Reticulum (ER) is a large network of membrane-bound tubes and sheets. It looks like long tubules or round/oblong bags (vesicles). The ER membrane is similar in structure to the plasma membrane. It serves as a channel for the transport of materials (especially proteins) between various regions of the cytoplasm or between the cytoplasm and the nucleus.
Types of Endoplasmic Reticulum
There are two types of ER based on the presence or absence of ribosomes on their surface:
1. Rough Endoplasmic Reticulum (RER)
Appearance: It looks rough under a microscope because it has particles called ribosomes attached to its surface.
Function: The ribosomes are the sites of protein manufacture. The manufactured proteins are then sent to various places in the cell depending on need, using the ER.
2. Smooth Endoplasmic Reticulum (SER)
Appearance: It appears smooth because it lacks ribosomes.
Function: It helps in the manufacture of fat molecules, or lipids, important for cell function. Some of these proteins and lipids help in building the cell membrane. This process is known as Membrane Biogenesis.
Detoxification: In the liver cells of the group of animals called vertebrates, SER plays a crucial role in detoxifying many poisons and drugs.
Comparison: RER vs SER
| Feature | Rough ER (RER) | Smooth ER (SER) |
|---|---|---|
| Ribosomes | Present on surface | Absent |
| Main Function | Synthesis of proteins | Synthesis of lipids/fats |
| Special Role | Sends proteins to Golgi | Detoxification (in liver) |
Key Concepts Revision
- Membrane Biogenesis: The process where proteins and lipids synthesized by the ER help build the cell membrane.
- Transport Channel: The ER serves as a pathway for the distribution of materials within the cell.
- Cytoskeleton: The ER also functions as a cytoplasmic framework providing a surface for some of the biochemical activities of the cell.
Extra Practice Questions
- What is the primary difference in appearance between RER and SER?
- Which organelle is responsible for detoxifying poisons in liver cells?
- Define membrane biogenesis.
- Why is RER important for cells that secrete enzymes?
- How does the ER facilitate transport within the cell?
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