Life Science ePrep Course

Sample Core Concepts

(on DNA Structure and Function)

1 Organisms alive today are linked by lines of descent from shared ancestors.

  • Shared core processes and features provide evidence that all living things are related.
  • A series of historical experiments led to the discovery that DNA is the primary source of heritable information for all life.
  • This information passes from parent to offspring during processes of reproduction.
  • DNA replication ensures the continuity of hereditary information, and so it maintains the continuity of life.

2 Living systems store, retrieve, transmit, and respond to information essential for life.

  • DNA in each cell encodes all of the instructions necessary for growth, survival, and reproduction of the cell and (in multicelled organisms) the individual.
  • The double-stranded structure of DNA is a simple, efficient way of storing this gigantic amount of information; it also allows a DNA molecule to be copied with high fidelity for transmission to offspring.

3 Interactions among the components of each biological system give rise to complex properties.

  • Random changes in DNA that are not repaired become mutations, which can alter the structure and function of cells, and also of multicelled organisms.
  • DNA replication is a source of mutations because it is an imperfect process.
  • Exposure to some environmental factors also results in mutations.
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