The Importance of DNA to Biology Nathan Money 2 nd period August 3, 2011 Watson & Crick with their DNA model in 1953.

The Importance of DNA to Biology

Nathan Money2nd periodAugust 3, 2011

Watson & Crick with their DNA model in 1953

What is DNA?

• Deoxyribose nucleic acid• DNA is the nucleic acid that holds all of our genetic material • Made of a phosphate group, a nitrogenous base, and a sugar

The Central Dogma

• The DNA holds the material that will eventually turn into proteins which express traits. – Genotype Phenotype

• The DNA transcribes into RNA through the replication mechanisms, RNA translates in the ribosomes into proteins, proteins form structures or perform specific jobs

Alleles

• Alleles are different forms of genes that combine to form a specific phenotype

• Half of the alleles that determine a phenotype are inherited from the mother, the other half are inherited from the father

Example:If a flower inherits one allele for red (RR) flowers from one

parent and an allele for white (rr)flowers from another parent the flower will have pink (Rr) flowers.

DNA Mutations• DNA mutations are changes in the

sequence of the nucleic acids. • Changes in DNA sequences can have a

major impact on bodily functions, or they can have little impact at all

• As you age there are mistakes in the replication of DNA, this is why aging occurs. (i.e. wrinkles). These tiny mistakes are DNA mutations

• However if the DNA mutates along an oncogene (gene controlling growth), either cells can stop growing or they continously grow (cancer).

RNA’s Importance to Evolution• RNA was one of the first nucleic

acid to appear in cells. It behaved as an enzyme and as a storehouse for genetic material

• RNA performing a double role in the cell provided for greater complexity in proteins and storage molecules for genetic material, because it was also a catalyst

• DNA replaced RNA because it is more stable and proteins took over the enzymatic role because of the greater variety of enzymes that could be formed due to monomers (amino acids)

The Human Genome Project

• An international science project whose main goal is to determine and map the 20,000-25,000 genes in the human genome

• Began in 1989 and was finished in 2003

Importance of the Project

• The project was successfully able to map the entire human genome

• This information will allow us to determine which genes are responsible for certain bodily functions – Thus allowing us to determine the genes at fault for certain diseases,

helping to further the cause of curing deadly diseases

Viruses• Viruses are simple infectious agents that implant DNA into a

host cell in order to reproduce• First the DNA attaches to the cell membrane of a cell and injects

its DNA or RNA• The genetic material combines with the material of the host • The host cell creates and assembles the components for more

viruses • The new viruses burst through the cell membrane and infect

new cells

Viral Reproduction

Importance of Viruses to Biology

• Viruses sometimes act as a transport system for delivering new DNA to cells.

• When the virus injects the DNA into the host cell the cell incorporates part of the DNA.

• If the host cell survives the new DNA will be passed along to the offspring, creating a new trait in the cell’s species.