Cell Wall Structure and Composition

Cell Wall

• The cell wall is the outermost covering in many organisms, surrounding the cell membrane.
• Found in prokaryotic cells, fungi, and plant cells.
• Provides protection, shape, strength, and support to the cell.
• Composed of different materials in different organisms:
  • Plant cells: cellulose, hemicellulose, and pectin.
  • Fungal cells: chitin.
  • Prokaryotic cells: peptidoglycan.
• Plant cells have two types of cell walls:
  • Primary cell wall: mainly consists of cellulose, hemicellulose, and pectin.
  • Secondary cell wall: contains cellulose and other molecules like lignin, making it stronger.

Cytoplasm

• A semitransparent substance between the plasma membrane and nucleus.
• Contains water with dissolved organic and inorganic materials.
• Provides space for metabolic reactions, such as glycolysis.
• Also provides space for the functioning of organelles and metabolic reactions.

Cytoskeleton

• The skeletal framework of the cell, consisting of a network of filaments and tubules.
• Three types of cytoskeletal elements:
  • Microfilaments: smallest in diameter, composed of helical chains of actin protein, involved in movement of organelles and cells.
  • Intermediate filaments: intermediate in size, composed of keratin proteins, involved in maintaining shape and placement of cells and organelles.
  • Microtubules: largest in diameter, composed of tubulin protein, involved in movement of organelles and cells, and maintaining shape of organelles and cells.
• Cilia and flagella consist of microtubules.
• The nuclear lamina, a layer that maintains the shape of the nucleus and provides support, is composed of microtubules.