Multi-Systems: Aging and Neoplasias

Question 1

Somatic Mutation Theory

Answer 1

• Proposes that Genetic Damage from Ionizing radiation produces mutations in DNA leading to Failure in Critical bodily functions

Question 2

DNA Repair Theory

Answer 2

• States that the Inability to Repair DNA Damage is responsible for Age-related and Dependent detrimental Effects

Question 3

Cross-Linking Theory

Answer 3

• Increased Cross-linking of Proteins in the Extracellular Matrix (collagen, elastin, crystallin) impairs the diffusion of Essential Nutrients to Tissue.
• Nonenzymatic glycosylation (a type of cross-linking involving glucose attachment to proteins) is also thought to impair diffusion of Essential Nutrients to Tissue
  
  • Glycosylation of collagen and the lens of the eys protein crystallin is a/w Cataracts in elderly.

Question 4

Free Radical Theory

Answer 4

• Most aging changes are due to Free Radical damage of Cell Membranes and Nuclear Proteins
• Evidence supports an Inverse Relationship between Free Radical production and Maximum Life-span
  
  • High Levels of Free Radicals metabolizing enzymes (e.g. Superoxide dismutase) have been found in Longer-lived species)

Question 5

Programmed Cell Death Theory

Answer 5

• Process of Aging is part of a genetically programmed Continuum of Development and Maturation
• Supported by the Similarity of Attained Age in Identical versus Nonidentical twins –> Increased longevity in Certain families and the presence of Genetic defects in people w/ Premature Aging (Down syndrome, progeria)