Endomembrane System

The endoplasmic reticulum (ER), Golgi Complex, Lysosomes, and Vacuoles are components of the endomembrane system.

Endoplasmic Reticulum (ER)

Endoplasmic Reticulum is a network or reticulum of minute tubular structures that are dispersed throughout the cytoplasm. The two forms of ER, known as rough ER and smooth ER, can be distinguished by differences in certain morphological and functional properties.

• Rough Endoplasmic Reticulum: RER refers to the endoplasmic reticulum that has ribosomes on its surface.
• Smooth Endoplasmic Reticulum: These are known as smooth endoplasmic reticulum (SER) when there are no ribosomes present.

Functions of Endoplasmic Reticulum

• RER is typically seen in cells that are actively producing and secreting proteins. They extend far and are contiguous with the nucleus’s outer membrane.
• The principal location for lipid synthesis is the smooth endoplasmic reticulum. Steroid hormones that resemble lipids are produced in animal cells by the SER.

Golgi Apparatus

A Golgi body, often referred to as a Golgi apparatus, is an organelle found in cells that aid in the processing and packaging of proteins and lipid molecules, particularly proteins intended for cell export. The Camillo Golgi-named Golgi body consists of a collection of membranes.

Structure of Golgi Apparatus

They are composed of several flat, disc-shaped sacs or cisternae that range in diameter from 0.5 to 1.0 m. These are stacked parallel to one another. There are different amounts of cisternae in a Golgi complex. The developing face of the Golgi cisternae is convex, and the mature face is concave, and they are concentrated close to the nucleus. The cis and trans faces of the organelle are entirely separate but connected.

Functions of Golgi Apparatus

• The primary site of glycoprotein and glycolipid synthesis is the Golgi apparatus.
• Its primary function is to bundle chemicals for delivery to intracellular destinations or for secretion outside the cell.

Lysosomes

Lysosomes are membrane-bound vesicles created during the Golgi apparatus packing process. It has been discovered that the isolated lysosomal vesicles are extremely rich in practically all varieties of hydrolytic enzymes that are most active at the acidic pH.

Functions of Lysosome

Lysosomal vesicles contain hydrolytic enzymes that can break down lipids, proteins, carbohydrates, and nucleic acids.

Vacuoles

The membrane-bound compartment in the cytoplasm is known as the vacuole. Water, sap, excretory material, and other substances are present. Tonoplast is the given name of the isolated membrane that surrounds the vacuole. In plant cells, vacuoles possess the capacity to consume up to 90% of the entire cell volume.

Functions of Vacoule

• In plants, the tonoplast helps with the movement of various ions and other substances up concentration gradients and into the vacuole.
• The contractile vacuole in amoebas is crucial for excretion and osmoregulation. Food vacuoles are created by enveloping the food particles in numerous cells, just like in protists.

Class 11 Biology NCERT Notes for Chapter 8 Cell The Unit of Life: Cells are the basic units of life and serve as the building blocks of all living organisms. They differ in structure, composition, and function, but have similarities. The human body is made up of more than trillions of cells. They give structure to the body, extract nutrients from food, convert those nutrients into energy, and perform specific functions.

NCERT Notes for Chapter 8 Cell The Unit of Life further explains that cells also contain the body’s genetic material and can make copies of themselves. A bacterium or yeast is often a distinct, complete organism as it is single-celled or unicellular. Other cells acquire special functions as they mature. Understanding the structure and function of cells is crucial for comprehending the complexity of biological systems.