Question

The surface of the endoplasmic reticulum is covered by
(a) Glucose
(b) DNA
(c) Ribosomes
(d) RNA

Answer 1

Hint: Non-membrane granular structures that contain RNA and proteins help in the synthesis of proteins and provide space for enzymes.

Complete answer:
One of the important cell organelle present in the eukaryotic cell is the endoplasmic reticulum. It is of two types namely rough endoplasmic reticulum and smooth endoplasmic reticulum. The surface of the rough endoplasmic reticulum is covered by ribosomes and the smooth endoplasmic reticulum is devoid of ribosomes. Ribosomes present on the surface of the rough endoplasmic reticulum helps in the synthesis of proteins.

Additional Information: A series of flattened sacs present inside the cytoplasm of a eukaryotic cell that performs various functions like protein synthesis, modifications of proteins, and transport of proteins is called the endoplasmic reticulum.
- It is surrounded by two membranes, the outer membrane, and the inner membrane
 On the rough endoplasmic reticulum, ribosomes are attached to the surface. Due to the presence of ribosomes, it plays an important role in the synthesis of proteins.
-Smooth endoplasmic reticulum is devoid of ribosomes. It plays an important role in synthesizing lipids. In animal cells, lipid-like steroidal hormones are synthesized in the smooth endoplasmic reticulum.
- Small granular structures present inside the prokaryotic and eukaryotic cells are called
ribosomes. They are non-membrane-bound structures.
- Ribosomes in eukaryotes are 80s types and in prokaryotes are70s types.
- 80s ribosomes have 60s and 40s subunits whereas 70s ribosomes have 50s and 30s subunits.
So, the correct answer is ‘ribosomes’.

Note: -The term endoplasmic reticulum was coined by K.Porter in 1953.
-Some of the proteins are stored in the endoplasmic reticulum and later they are sent into the Golgi apparatus which lies next to the endoplasmic reticulum.
-George palade in 1953 first observed ribosomes under an electron microscope.