Chapter 9 & 10 notes
- 1. CHAPTER 9 & 10 NOTES DNA STRUCTURE & FUNCTION
- 2. What is DNA? Nucleic acid – a compound composed of a 5-carbon sugar, a nitrogen base, and a phosphate. Deoxyribonucleic acid – DNA – controls the cells activities, carries genetic information. It is found in the nucleus of the cell.
- 4. Who discovered DNA? DNA was discovered in the late 1940’s, but the structure was not discovered until 1953 . Two scientists named James Watson and Francis Crick came up with a model of the structure of DNA.
- 5. What does Watson and Crick’s DNA model look like? The shape looks like a twisted ladder – double helix . Each side is made up of alternating sugar and phosphate molecules. The sugar in DNA is called deoxyribose. Attached to each sugar is a nitrogen base . To make the ladder complete, each base is joined by a weak hydrogen bond to a base on the other side.
- 7. What are the nitrogen bases? There are 4 different nitrogen bases in DNA: 1. guanine - G 2. thymine - T 3. adenine - A 4. cytosine - C
- 8. How do the bases bond? The nitrogen bases always bond in the same way: adenine to thymine A - T guanine to cytosine G - C
- 9. Base Pairing
- 11. How are these parts put together? DNA is built up in small units. Each unit is made up of a sugar , a phosphate , and a nitrogen base . This small unit is called a nucleotide .