1. DNA What are nucleic acids? Why is DNA important? Structure of DNA Scientists

2. Review What are the two types of nucleic acids? _________________ & _______________ Is a nucleic acid a monomer or polymer? __________________________ What is the monomer of DNA and RNA? _________________________ DNARNA POLYMER nucleotide

3. DNA Location DNA stands for deoxyribonucleic acid Location: DNA is found in the nucleus of eukaryotic organisms – like plants, animals, protists and fungi In prokaryotic organisms (like bacteria) that do not have a nucleus, DNA can be found in a single circular chromosome within the cell

5. DNA Function Function: DNA stores and carries the information that is passed from one organism to its offspring (from parent to child)

6. What is DNA? The information is coded in the order of the nucleotide bases (the monomers) The monomer of DNA is made of: – Phosphate group – 5 carbon sugar (deoxyribose) – Nitrogen containing base These three components make the monomer called a nucleotide

7. Nucleotide

8. Why is DNA Important? DNA is in all living things DNA is the informational code that makes each organism unique.

9. The Structure of DNA double helix- two strands of nucleotides twisted around each other, like a winding staircase there is a “right side up” strand and an “upside down” strand. this arrangement of 2 strands running side by side but in opposite directions is described as antiparallel

11. The Structure of DNA Nucleotides- subunits (monomers) that make up DNA composed of: – Phosphate group – 5- carbon sugar (deoxyribose in DNA) – Nitrogen containing base: The bases pair in the same way in every DNA molecule, we call this complementary base pairing Adenine Thymine (A – T) Guanine Cytosine (G – C) * Weak hydrogen bonds hold bases together

12. Base Pairs We refer to adenine, thymine, cytosine and guanine as the nitrogen bases or just “bases” So, when you say “a sugar, a phosphate and a base” you are implying that the base is either adenine, thymine, guanine or cytosine

14. Base Pairs The order of the base pairs provides that “unique code” that makes us all different. GTAACTTAG does not contain the same information as GGACAATTT even though both sequences contain the same nucleotides However, if the nucleotide sequences of nitrogenous bases (adenine, guanine, cytosine, thymine) are in a similar order, the more related two organisms are closely related – This concept is used in forensic science and is called DNA fingerprinting

15. Label complementary bases and draw the appropriate number of hydrogen bonds  A C A T G T A C T G T A C A T G

16. The Structure of DNA *Note about bases: – Pyrimidines- single ring of carbon Tymine and Cytosine – Purine- two rings of carbon Adenine and Guanine A purine must always hydrogen bond with a pyrimidine!

18. A C Label: -Phosphate (P) -5 carbon sugar (S) - Correct base pairs (A, T, C, G) -Label all hydrogen bonds with an H -Label the 5’ and 3’ ends Circle a nucleotide A T G A P P P P P P P P P P P P S S S S S S S S S S S S T T G A T C H H H H H H 3’ 5’