word of the day hydrogen bonds: –weak bonds that hold the bases of dna together
TRANSCRIPT
Word of the Day
• Hydrogen Bonds:– Weak bonds that hold the bases of DNA
together
History of DNA
Milestones
1869: Johann Friedrich Miescher
• Identifies an acidic substance, of unknown function, in the nuclei of human white blood cells.
• Calls it DNA
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressorare needed to see this picture.
1924
• DNA and proteins are present in the cell’s nucleus.
• Which one is the genetic information?
QuickTime™ and a decompressor
are needed to see this picture.
No one knows!
1944: Oswald Avery
• Identifies DNA as the genetic material
• Most scientist did not believe that it was the genetic material because DNA is so simple
QuickTime™ and a decompressor
are needed to see this picture.
1949: Erwin Chargaff
• finds that the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine in DNA from every species.
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressorare needed to see this picture.
1951: Rosalind Franklin
• What did this picture show her?
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
1953: James Watson and Francis Crick
• discover the molecular structure of DNA
QuickTime™ and a decompressor
are needed to see this picture.
DNA Structure:
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
1991: Human Genome Project
• Goal: to map out the human genes
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
Information Set #1
• *DNA is a polymer. A polymer is a very long, chainlike molecule made of smaller sub unit molecules.
• *These subunits are like links in a chain.
• *They are attached by covalent bonds
• *Four different subunits exist.
Information Set #2
• *DNA consists of two long chains of these 4 subunits
• * The subunits each have a sugar, a phosphate and a base - called a nucleotide
• *These chains are twisted around each other in a double helix. (A helix is the shape a pipe cleaner takes when it is twisted around a pencil)
• * The two chains are held together with weak hydrogen bonds at the bases.
Information Set #3
• *The order of the subunits in one strand determine the order of the subunits in the other strand.
• *The sugar and phosphate form a “backbone” to the polymer.
Assignment: Poster
Title
Vocab List
Paragraph describing structure
Vocabulary words
• Nucleotide
• Nitrogen bases
• Chargaff’s rules
• Double helix
• Hydrogen bonds
• Sugar
• phosphate