Cell Biology History

Cell Biology

• Cells are the structural and fundamental units of life, capable of performing basic functions of all living organisms.
• Cytology is the scientific study of the structure and composition of cells.

History of Cell Discovery

• Robert Hooke first observed cells in a thin slice of cork in 1665, marking the beginning of our understanding of cellular existence.
• Anton Van Leeuwenhock discovered the first free-living cell in 1674.
• Robert Brown discovered the nucleus in 1831.
• J.E.Purkinje discovered protoplasm in 1839.

Cell Theory

• The cell theory was given by Schleiden and Schwann in 1838, stating that:
  • All living things are made up of cells.
  • Cells come from pre-existing cells through the process of cell division.

Cell Organelles

• Protoplasm is the essential substance within cells, comprising water, ions, salts, organic molecules, cell organelles, and a nucleus, existing in sol-gel states.
• Ribosomes translate genetic instructions from mRNA to build proteins essential for cell structure and function.
• Plastids are membrane-bound organelles found in plant cells, responsible for crucial processes like photosynthesis.

Types of Plastids

• Chloroplasts:
  • Contain chlorophyll pigments, essential for photosynthesis.
  • Found in cells of green plant tissues.
  • Chlorophyll absorbs light energy and converts it into chemical energy.
• Chromoplasts:
  • Contain various pigments such as carotenoids (e.g., carotenes and xanthophylls).
  • Involved in the synthesis and storage of pigments other than chlorophyll.
  • Give fruits and flowers their characteristic colors.
• Leucoplasts:
  • Colorless and do not contain pigments like chlorophyll or carotenoids.
  • Involved in the storage of starch, lipids, or proteins.