Biochemistry Cell History Discussion

History of Cell Discovery

• Cells are fundamental units of life, discovered by Robert Hooke in 1665.
• Hooke observed cork under a microscope and identified small structures he named "cells."
• Due to limited magnification, Hooke believed these structures were non-living.
• Anton Van Leeuwenhoek later observed motility in cells, concluding they were alive and called them "animalcules."
• Robert Brown identified the nucleus in orchid cells in 1883, enhancing understanding of cell structure.

Cell Theory

• Proposed by Theodor Schwann, Matthias Schleiden, and Rudolf Virchow.
• States:
  • All living organisms are composed of cells.
  • The cell is the basic unit of life.
  • All cells arise from pre-existing cells.
• Modern cell theory includes:
  • Energy flows within cells.
  • Genetic information is transferred between cells.
  • All cells share a similar chemical composition.

Functions of Cells

• Cells provide support and structure, forming the basis of all organisms.
• Components like cell walls and membranes maintain this support.
• Hereditary material in cells can be DNA or RNA.
• Prokaryotic cells reproduce via binary fission and conjugation.
• Eukaryotic cells have a true nucleus and can reproduce sexually and asexually.

Prokaryotic vs Eukaryotic Cells

• Prokaryotic cells:
  • Lack a true nucleus.
  • Size: 0.1 to 0.5 µm.
  • Include archaea, bacteria, and cyanobacteria.
• Eukaryotic cells:
  • Contain a true nucleus, size ranging from 10 to 100 µm.
  • Include plants, fungi, protozoans, and animals.
  • Plasma membrane regulates nutrient transport and cell communication.

Cell Structure

• Comprised of components with specific functions essential for life processes:
  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Nucleus
  • Cell organelles

Cell Membrane

• Serves as the outer covering of the cell, supporting and protecting it.
• Controls movement of substances in and out, maintaining internal environment.
• Also referred to as the plasma membrane.

Cell Wall

• Not present in animal cells; found exclusively in plant cells.
• Composed of cellulose, hemicellulose, and pectin.
• Provides rigidity, shape, and mechanical protection to plant cells.

Cytoplasm

• Thick, clear, jelly-like substance where most chemical reactions occur.
• Contains organelles such as endoplasmic reticulum, vacuoles, and ribosomes.

Nucleus

• Contains hereditary material (DNA); sends signals for cell growth and division.
• Surrounded by the nuclear envelope, separating it from the cytoplasm.

Cell Organelles

• Golgi Bodies: Involved in the transportation of materials within the cell, often called the "post office" of the cell.
• Ribosomes: Synthesizers of proteins, crucial for cell function.
• Mitochondria: Known as the “powerhouse of the cell,” responsible for producing ATP, the cell's energy currency.
• Lysosomes: Protect the cell by digesting foreign bodies; often referred to as the cell’s "suicide bags."
• Chloroplasts: Involved in photosynthesis and contain chlorophyll, the pigment essential for capturing light energy.
• Vacuoles: Store food, water, and waste materials, playing a role in cell renewal.

Explore the fascinating history of cells in biochemistry. This discussion covers key figures such as Robert Hooke, who discovered cells in 1665, as well as the fundamental concepts surrounding the cell as the basic unit of life. Test your knowledge on these critical components of biological science.