write a short note on nucleus, plastids and endoplasmic reticulum
Answers
1) The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
2) The plastid is a membrane-bound organelle found in the cells of plants, algae, and some other eukaryotic organisms. Plastids were discovered and named by Ernst Haeckel, but A. F. W. Schimper was the first to provide a clear definition.
3) The endoplasmic reticulum is a type of organelle found in eukaryotic cells that forms an interconnected network of flattened, membrane-enclosed sacs or tube-like structures known as cisternae. The membranes of the ER are continuous with the outer nuclear membrane.
◼Nucleus:
The nucleus is a membrane bound organelle that contains the hereditary information of the cell and controls the growth and reproduction of the cell. It is the main part of the cell. It is surrounded by the nuclear membrane. It is termed as the brain of the cell.
◼Plastids:
Plastids are the site of manufacture and storage of important chemical compounds used by plant cells. They are double membrane bound structures. They often contain pigments which are used in the process of photosynthesis, and the type of pigments in a plastid determine the color of the cell. They are known as the kitchen of the cell.
◼Endoplasmic Reticulum:
Endoplasmic reticulum is a network of membranous tubes within the cytoplasm of a cell, continuous from the nuclear membrane. It usually has ribosomes attached to it and is involved in proteins and lipids synthesis. It is divided into two- Rough and Smooth endoplasmic reticulum. The two divisions have their own functions.