21 Cellular Changes During Aging

Cellular Plasma Membrane Changes

• As the cell ages the plasma membrane has an increases amount fatty acids.
  • This structural change decreases the fluidity of the plasma membrane and reduces the transportation of ions, nutrients, amino acids, and proteins across the membrane.

Nuclear Changes

• As the cell ages cross-linkages form between the sulfur atoms on the DNA in the nucleus of the cells.
  • This structural change condenses the DNA which decreases the synthesis of RNA, reduced the cells ability to repair enzymes, and may reduce the cell’s ability to divide.

Cytoplasmic Changes

• As the cell ages the volume of cytoplasm increases, enzymes that synthesize DNA move from the nucleus to the cytoplasm, and there is a gradual build up of lipofuscin.
  • While it is unclear how this directly affects the cell, it is known that once the DNA migrates from the nucleus it is unable to synthesizes enzymes.

Ribosomal Changes

• As the cell ages the amount of ribosomal RNA and the number of ribosomes decreases.
  • This structural change results in a decreased level of protein synthesis.

Mitochondrial Changes

• As the cell ages the number of mitochondrial present in a cell decreases.
  • This structural change reduces the cell’s ability to produce energy.

Lysosomal Changes

• As the cell ages the lysosomes become less able to break down waste proteins, nucleic acids, carbohydrates, and fats.
  • This results is a build up waste within the cell.