The Fundamental Unit of Life Test - 14

Plastid is the largest cell organelle in a plant. It contains chlorophyll necessary for photosynthesis. Plastid is the site of manufacture and storage of important chemical compounds used by the plant cell.

Lysosome is called as the suicide bag of the cell as it contain enzymes for hydrolysis of all cell components in case of injury. It plays a minor role in cell death. It was discovered and named by Belgian biologist Christian de Duve. De Duve had termed the organelles as the "suicide bags" or "suicide sacs" of the cells. He received the Nobel Prize in Medicine in 1974 for his discovery.

Lysosomes present in the cytoplasm of a cell contain very strong enzymes that can break down the organic wastes produced in the cell. They are called as garbage disposal system of the cell.

Lysosomes are the reservoirs of hydrolytic enzymes. These enzymes help in waste disposal of the cell. Hydrolytic enzymes can hydrolyze the complete cell in case of injury.

Lysosome is called as digestive bag as it contains hydrolytic enzymes that help in the digestion of food and hydrolysis of cell constituents. It is also called as "suicide bag".

When a cell is placed in a hypotonic solution, the cell swells up due to endosmosis of water molecules from the region of higher concentration to the region of lower concentration.

A solution having higher concentration than that inside the cell is known as a hypertonic solution. If a cell is placed in such a solution, exo-osmosis will take place and the cell will shrink.

Plasmolysis is the shrinkage of cytoplasm due to movement of water from cell (loss of water) to the surrounding medium having lesser water concentration. The shrinkage of cytoplasm occurs due to ex-osmosis in a hypertonic medium. A hypertonic solution (outside the cell) is one which has a lesser concentration of water as compared to that inside the cell. 

Plant cells lack centrosomes or spindle pole bodies which act as the microtubule organizing centers in animal cells. Centrioles are a very important part of centrosomes. The function of chromatid separation in plants is performed by polar cap during cell division. 

Mitichondria have their own DNA and ribosomes. They can self-replicate.
The longest cells in the human body are neurons. Neurons or the nerve cells form the basic component of the nervous system. They have a typical structure.
Chromoplasts are coloured plastids. Leucoplasts are white or colourless plastids. Plastids are present only in plant cells. Plastids are similar to mitochondria in external structure. Like the mitochondria, plastids have their own DNA and ribosomes.
Chromatin material is entagled mass of thread-like structures inside nucleus. The DNA is present as part of chromatin material which gets organised into chromosomes when the cell is about to divide.