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NUCLEIC ACIDS

NUCLEIC ACIDS . Below is one of the molecules that makes up DNA. What functional groups do you see in the molecule:. Hydroxyl Carboxyl Amino Phosphate. Functions of DNA. Control the processes of heredity by which cells and organisms reproduce proteins. Types of Nucleic Acids.

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NUCLEIC ACIDS

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  1. NUCLEIC ACIDS

  2. Below is one of the molecules that makes up DNA. What functional groups do you see in the molecule: • Hydroxyl • Carboxyl • Amino • Phosphate

  3. Functions of DNA • Control the processes of heredity by which cells and organisms reproduce proteins

  4. Types of Nucleic Acids • DNA (deoxyribonucleic acid): double-stranded • RNA (ribonucleic acid): single-stranded

  5. Nucleic Acid Structure • The monomer units of DNA are known as nucleotides • All nucleotides have three “parts” in common: • Phosphate “backbone” • Pentose sugar (ribose or deoxyribose) • Nitrogen base

  6. Deoxyribose Sugar (DNA) • Has 5 carbons and 3 oxygens • Carbon atoms are numbered 1', 2', 3', 4', and 5' • Distinguishes from the numbering of the atoms of the purine and pyrmidine rings • 5'-carbons link to the phosphate groups • 3'-carbons link to the hydroxyl groups

  7. Direction of the nucleotides in one strand is opposite to their direction in the other strand: the strands are antiparallel. • Asymmetric ends of DNA strands are called the 5′ (five prime) and 3′ (three prime) ends • 5' end having a terminal phosphate group • 3' end having a terminal hydroxyl group

  8. Nitrogen Bases • Weak hydrogen bonds connect complementary nitrogen bases • Two types: • Pyrimidines: form hexagon shaped rings • Cytosine • Thymine (only DNA) • Uracil (only RNA)

  9. Purines: combination of a pentagon shaped ring and a hexagon shaped ring • Adenine • Guanine

  10. Nitrogen Base Pairing • Adenine and Thymine must form two hydrogen bonds to be stable while Guanine and Cytosine must form three • Makes the base pairing system an extremely simple: the A-T and C-G pairs are the only ones physically possible

  11. Let’s Practice How to Form DNA!

  12. PHOSPHATE NITROGEN BASE SUGAR We will use our hands to represent a nucleotide.

  13. A T G C The four different Nitrogen Bases for DNA are abbreviated using the following letters…. Adenine Thymine Guanine Cytosine

  14. Using your two hands, please show how you think two nucleotides will/should bond together. Did you put your hands like this???

  15. Time to find out why this is wrong!!!

  16. LOOK! TWO RINGS!!! Adenine and Guanine are larger molecules known as… PURINES

  17. LOOK! Only one ring!! THYMINE and CYTOSINE are smaller molecules known as… PYRIMIDINES

  18. Full Finger Half Finger Now, when using our hands to represent the nucleotides, we must modify the nitrogen base in order to represent these PURINES and PYRIMIDINES. How would you represent a large PURINE? How would you represent a small PYRIMIDINE?

  19. In DNA, a PURINE always bonds with a PYRIMIDINE when forming a “rung” of the DNA ladder. LOOK! A long finger pairs with a short finger! In other words, a purine pairs with a pyrimidine.

  20. T A In DNA, Adenine always pairs with Thymine using two hydrogen bonds.

  21. C G In DNA GUANINE always pairs with CYTOSINE using three hydrogen bonds.

  22. Time to use your brain and hands in order to review nucleotide structure and type. USING YOUR HAND, SHOW ME THYMINE USING YOUR HAND SHOW ME ADENINE SHOW ME CYTOSINE SHOW ME HOW CYTOSINE AND THYMINE BOND TO FORM A RUNG ON THE LADDER THEY DON’T

  23. OK Now that you recognize nucleotide type and structure, it’s time to start building the polymer from these monomers.

  24. The molecules marked “W” are best described as: • Monomers • Polymers • Isomers • isotopes

  25. Reactions A and B are respectively known as: • Dehydration, hydrolysis • Condensation, hydrolysis • Polymerization, decomposition • Hydrolysis, dehydration A B

  26. Molecule(s) “X” are most likely: • Carbohydrates • Monomers • Polymers • Water • Starch

  27. If molecule “W” is a nucleotide, molecule marked “Y” is most likely: • Protein • Starch • DNA • Galactose • Fructose

  28. Look. Many Rungs. Etc… In order to make a molecule of DNA, you would need to create many rungs to the DNA ladder.

  29. Sugar, Phosphate. Sugar, Phosphate. Sugar, Phosphate. Etc… What part of the nucleotide alternates to form the sides of the DNA ladder? Etc…

  30. The Nitrogen Bases What makes up the “RUNGS” of the ladder?

  31. Go Ahead! Stack you hand on top of your partners hands building two rungs of the DNA ladder.

  32. Why is this WRONG????

  33. The sides of the DNA ladder “run” in opposite directions. One side is actually flipped and the nucleotides are upside down!

  34. TRY IT!!!

  35. Because the sides of the DNA “run” in opposite directions, DNA is said to be ANTIPARALLEL.

  36. 5 prime 5 prime In this DNA molecule, the THUMB part or better known as the PHOSPHATE GROUP, is said to be the 5 prime (5’) end.

  37. 3 Prime 3 Prime The “hand” or sugar part of the DNA molecule makes up the 3 prime (3’) end of the DNA ladder.

  38. If you link enough nucleotides together, the DNA molecule begins to take on the characteristic shape known as the Double Helix

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