Question

The endoplasmic reticulum is present in?
A) Nucleus
B) Chromosomes
C) Nucleolus
D) Cytoplasm

Answer 1

Hint: Endoplasmic Reticulum can be defined as a complex network of tubular membranes which is exclusively present in the cytoplasm of the eukaryotic cell. They are of two types Smooth Endoplasmic Reticulum and Rough Endoplasmic Reticulum. Their main function is synthesis of cholesterol and phospholipids.

Complete answer:
The Endomembrane system is a membranous component of the eukaryotic cell and the organelles are suspended in the cytoplasm of the cell. The endoplasmic reticulum is the endomembrane system and presents in the cytoplasm. The general structure of the endoplasmic reticulum is a network of membranes called cisternae which are held together by the cytoskeleton.
Nucleus is the membrane bound organelle which maintains the integrity of cells by facilitating transcription and replication processes.
Chromosomes are thread-like structures which are made up of DNA and proteins.
Nucleolus is the site where transcription and processing of ribosomal RNA takes place.

So the correct answer is Option D.

Additional Information:
Components of the endomembrane system are endoplasmic reticulum, Golgi bodies, lysosomes, vacuoles.
Rough Endoplasmic Reticulum has a series of connected flattened sacs having several ribosomes on its outer surface, hence the name Rough Endoplasmic Reticulum. The main function is synthesis and secretion of proteins in liver, hormones in other glands. It is prominent in cells like hepatocytes.
Smooth endoplasmic reticulum does not have ribosomes. The main function is production of phospholipids. They transport the products of rough ER to other cellular organelles like Golgi apparatus.

Notes:
Components of the endomembrane system are endoplasmic reticulum, Golgi bodies, lysosomes, vacuoles.
The voluminous vacuole is the membrane-bound space of the cytoplasm that occupies ninety percent volume of the plant cell. Tonoplast facilitates transport of ions against the concentration gradient into the vacuole which is the outermost membrane.
Lysosomes are known as the suicidal bag of the cell because they contain hydrolytic enzymes that digests carbohydrates, lipids and proteins.
Golgi bodies serve mainly as the packaging centre for endomembrane secretions like proteins.