DNA stores and passes on genetic information from one generation to the next. It has a double helix structure shaped like a spiral staircase with two strands connected by hydrogen bonds between complementary nucleotide base pairs. The four nucleotide bases are adenine, guanine, cytosine, and thymine, which always form specific base pairs between the strands through hydrogen bonding.

1. DNA THE ALPHABET OF LIFE

2. Stores and passes on genetic information from one generation to another. DNA DEOXYRIBONUCLEIC ACID

3. DNA STRUCTURE THE DNA STRUCTURE IS SHAPED LIKED A SPIRAL STAIRCASE, OR TWISTED LADDER.

5. The deoxyribose sugar of the DNA backbone has 5 carbons and 3 oxygens. DNA STRUCTURE

6. DNA STRUCTURE THE STEPS OF THE LADDER ARE MADE OF PAIRS OF NITROGEN BASES.

9. DNA STRUCTURE There is only one way the nitrogen bases can form ADENINE pairs with THYMINE GUANINE pairs with CYTOSINE

10. DNA STRUCTURE QUESTION ? CAN C JOIN WITH A AND G JOIN WITH T YES NO

11. CORRECT MOVE ON

12. SORRY REVIEW MORE

13. DNA STRUCTURE Nucleotides Nucleotides are formed by the condensation of a pentose sugar, phosphate and one of the 4 bases The following illustration represents one nucleotide CIRCLE = Phosphate PENTAGON= Deoxyribose Rectangle= Base

16. DNA STRUCTURE Antiparallel strands The strands run opposite of each other. The 5’ end always has the phosphate attached. ’

17. SAMPLE QUESTION Which of the following nucleotide base sequences complements the section of DNA modeled above? F. 5′UTCGCA3′ G. 5′TTAGCG3′ H. 5′GCGATT3′ J. 5′TTUCGC3′ 3′AATCGC 5′

18. SAMPLE QUESTION The Correct Answer: G G is the right answer because A (adenine) always pairs with T (thymine) and C (cytosine) always pair with (guanine).