9th Class Science: The Fundamental Unit of Life

Question: What are plastids? Name the different types of plastids found in plant cell.

Answer: Plastids are organelles found only in plants. They are:

1. Chloroplast-Containing chlorophyll
2. Chromoplast-Containing carotenoids and xanthophyll (coloured plastids)
3. Leucoplast-Wllite or colourless plastids

Question: What is plasma membrane made up of?

Answer: Plasma membrane is made up of proteins and lipids.

Question: What did Robert Hooke observed first in cork cell?

Answer: Robert Hooke observed that cork consists of box like compartments which formed a honeycomb structure.

Question: Name the autonomous organelles in the cell.

Answer: Chloroplasts and mitochondria are the autonomous organelles in the cells.

Question: What does protoplasm refer to?

Answer: Protoplasm refer to cytoplasm and nucleus.

Question: Name two cells which keep changing their shape.

Answer: Amoeba and white blood cells.

Question: Name the smallest cell and the longest cell in human body.

Answer: The smallest cell is the red blood cell or sperm cell in male. Longest cell is the nerve cell.

Question: Name 3 features seen / present in almost every cell.

Answer: Plasma membrane, nucleus and cytoplasm.

Question:What is diffusion?

Answer: When gases like CO₂, O₂, move across the cell membrane, this process is called diffusion.

Question:What is osmosis? This takes place from high water concentration to low water concentration.

Answer: The movement of water molecules through a selectively permeable membrane is called osmosis. This takes place from high water concentration to low water concentration.

Question: What is the full form of DNA?

Answer: DNA —> Deoxyribo Nucleic Acid.

Question: What is the Junction of chromosome?

Answer: Chromosomes contain information for the inheritance of features from parents to next generation in the form of DNA molecules.