E.R. was discovered by

Options

A. Palade
B. Porter
C. Thomson
D. Both B and C

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the discovery of the Endoplasmic Reticulum (E.R.).

2. **Definition of Endoplasmic Reticulum**: The Endoplasmic Reticulum is a network of membranes within the cell that plays a crucial role in the synthesis of proteins and lipids. It can be classified into two types: Rough Endoplasmic Reticulum (RER) and Smooth Endoplasmic Reticulum (SER).

3. **Types of Endoplasmic Reticulum**:
- **Rough Endoplasmic Reticulum (RER)**: This type has ribosomes attached to its surface, giving it a "rough" appearance. It is primarily involved in protein synthesis.
- **Smooth Endoplasmic Reticulum (SER)**: This type lacks ribosomes and is involved in lipid synthesis and detoxification processes.

4. **Discovery of the Endoplasmic Reticulum**: The Endoplasmic Reticulum was discovered by scientists George E. Palade, who is often credited with its discovery, and Keith R. Porter. They made significant contributions to cell biology and were recognized for their work in the year 1945.

5. **First Observation**: Although the discovery is attributed to Porter and Palade, the structure of the Endoplasmic Reticulum was first observed by Keith R. Porter.

**Final Answer**: The Endoplasmic Reticulum (E.R.) was discovered by George E. Palade and Keith R. Porter in 1945.

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