1. Basics of Cells:

• All living organisms are composed of cells.
• Cell is considered as the basic unit of life.

2. Types of Cells:

• There are two main types of cells: prokaryotic and eukaryotic.
• Prokaryotic cells do not have a nucleus or membrane-bound organelles. Bacteria are typical examples.
• Eukaryotic cells have a nucleus and membrane-bound organelles. Animals and plants are composed of eukaryotic cells.

3. Parts of a Eukaryotic Cell:

• Key parts of a eukaryotic cell include nucleus, cytoplasm, cell membrane, mitochondria and ribosomes.
• The nucleus controls the activities of the cell and contains genetic material.
• The cytoplasm is a gel-like substance where most of the chemical reactions occur.
• The cell membrane is responsible for controlling the passage of substances into and out of the cell.
• Mitochondria are the site of aerobic respiration and where most energy is released.
• Ribosomes are the site of protein synthesis.

4. Plant Cells and Animal Cells:

• In addition to all the parts present in an animal cell, a plant cell also has cell wall, chloroplasts and a permanent vacuole.
• Chloroplasts are where photosynthesis occurs.
• The cell wall provides added strength and support to the cell.
• Permanent vacuole contains cell sap, a weak solution of sugar and salts.

5. Specialised Cells:

• Cells may be specialised to carry out a particular function.
• Examples include sperm cells, nerve cells and root hair cells in plants.

6. Microscopy:

• Light microscopes allow us to see the cells and large organelles like nuclei.
• Electron microscopes have much higher resolution and magnification so smaller details, like ribosomes and plasmids, can be seen.

7. Cell division and Differentiation:

• Cells divide in a series of stages called the cell cycle.
• During the cell cycle, the genetic material is duplicated and then divided into two new cells.
• In mature animals, cell division is mainly used for repair and replacement.
• In plants, cells retain the ability to differentiate throughout life.
• Differentiation is the process by which a cell changes to become specialised for its job.