General Biology Chapter 16 Study Guide
Chapter 16 Notes: The Molecular Basis of Inheritance
Overview: Life’s Operating Instructions
In 1953, James Watson and Francis Crick introduced an elegant double-helical model for the structure of DNA.
DNA, the substance of inheritance, is the most celebrated molecule of our time.
Hereditary information is encoded in DNA and reproduced in all cells of the body.
This DNA program directs the development of biochemical, anatomical, physiological, and (to some extent) behavioral traits
Early in the 20th century, the identification of the molecules of inheritance loomed as a major challenge to biologists.
The search for the Genetic Material: Scientific Inquiry
When T.H. Morgan’s group showed that genes are located on chromosomes, the two components of chromosomes- DNA and protein- became candidates for the genetic material
The key factor in determining the genetic material was choosing approximate experimental organisms.
The role of DNA in heredity was first discovered by studying bacteria and the viruses that infect them.
Evidence that DNA can transform bacteria:
The discovery of the genetic role of DNA began with research by Frederick Griffith in 1928.
Griffith worked with two strains of a bacterium, one pathogenic and one harmless.
When he mixed heat-killed remains of the pathogenic strain with living cells of the harmless strain, some living cells became pathogenic.
He called this phenomenon transformation, now defined as a change in genotype and phenotype due to assimilation of foreign DNA.
In 1944, Oswald Avery, Maclyn McCarty, and Colin MacLeod announced that the transforming substance was DNA.
Their conclusion was based on experimental evidence that only DNA worked in transforming harmless bacteria into pathogenic bacteria.
Many biologists remained skeptical, mainly because little was known about DNA.
Evidence that Viral DNA can program cells
More evidence for DNA as the genetic material came from studies of viruses that infect bacteria.
Overview: Life’s Operating Instructions
In 1953, James Watson and Francis Crick introduced an elegant double-helical model for the structure of DNA.
DNA, the substance of inheritance, is the most celebrated molecule of our time.
Hereditary information is encoded in DNA and reproduced in all cells of the body.
This DNA program directs the development of biochemical, anatomical, physiological, and (to some extent) behavioral traits
Early in the 20th century, the identification of the molecules of inheritance loomed as a major challenge to biologists.
The search for the Genetic Material: Scientific Inquiry
When T.H. Morgan’s group showed that genes are located on chromosomes, the two components of chromosomes- DNA and protein- became candidates for the genetic material
The key factor in determining the genetic material was choosing approximate experimental organisms.
The role of DNA in heredity was first discovered by studying bacteria and the viruses that infect them.
Evidence that DNA can transform bacteria:
The discovery of the genetic role of DNA began with research by Frederick Griffith in 1928.
Griffith worked with two strains of a bacterium, one pathogenic and one harmless.
When he mixed heat-killed remains of the pathogenic strain with living cells of the harmless strain, some living cells became pathogenic.
He called this phenomenon transformation, now defined as a change in genotype and phenotype due to assimilation of foreign DNA.
In 1944, Oswald Avery, Maclyn McCarty, and Colin MacLeod announced that the transforming substance was DNA.
Their conclusion was based on experimental evidence that only DNA worked in transforming harmless bacteria into pathogenic bacteria.
Many biologists remained skeptical, mainly because little was known about DNA.
Evidence that Viral DNA can program cells
More evidence for DNA as the genetic material came from studies of viruses that infect bacteria.