DNA chapter 12 A. What is DNA? 1. The nucleic acid that stores - - PowerPoint PPT Presentation

DNA – chapter 12

• A. What is DNA?
• 1. The nucleic acid that stores

and transmits the genetic information from one generation to the next.

• B. What is the structure of DNA?
• 1. 4 nucleotides (phosphate, sugar, base)
• a. thymine
• b. cytosine
• c. adenine
• d. guanine
• 2. double helix
• a. sugar-phosphate backbone

1) sugar bonds to phosphate

• 3. Hydrogen bonds b/w complementary bases

• a. complementary:

adenine – thymine guanine - cytosine

Chromosomes and DNA Replication (chapter 12.2)

• A. DNA Replication: Nucleus ONLY!
• 1. Purpose: copy DNA when cell

divides  make a copy of chromosomes for new cell

• 2. Challenging due to:

a) length of DNA b) number of base pairs to correctly copy

• 3. Process: pg. 297-299
• a. parent DNA is separated by

enzymes (DNA helicase)

• b. free nucleotides floating around

nucleus bond to the parent strand (DNA polymerase)  new replicated strand (DNA Ligase)

• 2. Replicate the DNA strand:

A T G C T C C G T T A C G T A A C G

• 2. Replicate the DNA strand:

A T G C T C C G T T A C G T A A C G T A C G A G G C A A T G C A T T G C