3 parts of a Nucleotide A ring-shaped sugar called deoxyribose A phosphate group A nitrogenous base – this group makes nucleotides unique from one another

Nitrogenous Bases Purines – two rings Pyrimidines – one ring

DNA Structure - Double Helix Nucleotides are joined together by covalent bonds that connect the sugar of one nucleotide to the phosphate group of the next. Sugar-phosphate backbones on the outside

Hydrogen bonds form between bases that are across from one another in the double helix Bases on the inside

Pairing A (Adenine) pairs with T (Thymine) G (Guanine) pairs with C (Cytosine)

The DNA Structure Lets make our own complimentary strand. Sample Strand: A T G A C A T C C C A A Complementary Strand is:

The DNA Structure Lets make our own complimentary strand. Sample Strand: A T G A C A T C C C A A Check your answer: T A C T G T A G G G T T

Write the complementary strand ATGTCCGAT TACAGGCTA CATGGCTTA GTACCGAAT

DNA Replication The strand that is copied to form a new strand is called a template In replication of a double-stranded DNA, both original (parental) DNA strands are copied

DNA Replication: Step 1 2 nucleotide chains are separated. Replication fork. Chains are separated by an enzyme called a helicase which breaks hydrogen bonds.

DNA Replication: Step 2 DNA polymerase binds to the separated chains of DNA. As it moves down the chain new chains of DNA are assembled using complementary nucleotides.

When copying is finished, you have two separate helices, each consist of one of the original strands plus its copy.

Question 1 From the template below, write the complement. GCTTTAGTAC

Question 2 You have a strand of DNA. 25% of it is thymine. What percent is: Adenine? Guanine? Cytosine?

Question 3 You have a strand of DNA. 10% of it is thymine. What percent is: Adenine? Guanine? Cytosine?

Homework Due tomorrow: Paper pets questions. Read 10.1 - `Print and complete study guide due on Wednesday.