1. GETTING TO KNOW DNA: A REVIEW

2. DEOXYRIBONUCLEIC ACID
As you know, DNA stands for….
DEOXYRIBONUCLEIC ACID

3. Is DNA a monomer or polymer1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

4. What does it mean to be a monomer?
What does it mean to be a polymer???

5. If we were reviewing proteins, the monomer units would be:
Nucleic acids
Fatty acids
Sugars
Amino acids 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

6. If the monomer units of proteins are amino acids, the monomer units of DNA are known as….
NUCLEOTIDES

7. One of FOUR different NITROGEN BASES
All nucleotides have three “parts” in common. They all contain….
One of FOUR different NITROGEN BASES
Phosphate Group
Sugar= Deoxyribose

8. I am sure you recall, we used our hands to represent a nucleotide.
PHOSPHATE
NITROGEN BASE
SUGAR

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

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

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

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

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

14. How would you represent a large PURINE?
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?
Full Finger
How would you represent a small PYRIMIDINE?
Half Finger

15. 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.

16. In DNA, Adenine always pairs with Thymine using two hydrogen bonds.

17. In DNA GUANINE always pairs with CYTOSINE using three hydrogen bonds.

18. Time to use your brain and hands in order to review nucleotide structure and type.

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

20. The molecules marked “W” are best described as:
Monomers
Polymers
Isomers
isotopes 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

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

22. Molecule(s) “X” are most likely:
Carbohydrates
Monomers
Polymers
Water
Starch 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

23. If molecule “W” is a nucleotide, molecule marked “Y” is most likely:
Protein
Starch
DNA
Galactose
Fructose 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

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

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

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

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

28. Why is this WRONG????

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

30. TRY IT!!!

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

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

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

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

35. Let’s Build Some DNA!!

36. You Need… Two Pipe cleaners Two red twizzlers Two black twizzlers
Many toothpicks
Four different colored marshmallows

37. The marshmallows represent the nitrogen bases
The marshmallows represent the nitrogen bases. Let’s decide as a class what colors will represent the following nitrogen bases.
ADENINE=
CYTOSINE=
GUANINE=
THYMINE=

38. Person One Person Two Cut the black twizzlers into 1.5 cm pieces.
These will represent the phosphate groups
Person Two
Cut the red twizzlers into 3 cm pieces.
These will represent the sugars.

39. Add the twizzlers to the pipe cleaners.
Remember, you need to alternate SUGAR (red) AND PHOSPHATE GROUPS (black).
When you are finished, your strand should not end in the same color you started with!

40. Did you and your partner make the same number of nucleotides on the sides of your ladder?
If not, FIX IT!!!

41. Time to put together the two sides.
Using the toothpicks and marshmallows, you are to add the nitrogen bases to the sides of the ladder. Remember, the nitrogen bases “come off” the sugar part of the nucleotide. As a result, they should be coming off of the red twizzler.
Please use two of the same color marshmallows to represent one ADENINE and GUANINE. The BIG purines.
Please use only one marshmallow to represent THYMINE and CYTOSINE. The small pyrimidines.

42. Following your teachers directions, let’s build one long strand of DNA

43. Not enough information
A Particular strand of DNA contains 10 adenine molecules. How many thymine will it contain: 5 10 20
Not enough information 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

44. Not enough information
A strand of DNA is 20% Guanine molecules. What is the percent of thymine in the strand of DNA? 10 20 30 40
Not enough information 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

45. A particular strand of DNA is 40% guanine
A particular strand of DNA is 40% guanine. What is the percent of adenine in the same strand? 10 20 30 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

46. The molecule at the location identified by the arrow:
Adenine
Guanine
Sugar
Phosphate
thymine 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

47. The molecule at the location identified by the arrow:
Adenine
Guanine
Sugar
Phosphate
thymine 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

48. The molecule at the location identified by the arrow:
Adenine
Guanine
Sugar
Phosphate
thymine 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

49. The end of the molecule identified by the blue arrows:
Five prime
Three prime 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

50. The end of the molecule identified by the red arrows:
Five prime
Three prime 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

51. Because the sides of the DNA ladder run in opposite directions, DNA is said to be…
Parallel
Nonparallel
Antiparallel
proparallel 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

52. Stay Tuned!! We will answer this question tomorrow.
What is a GENE?
Stay Tuned!! We will answer this question tomorrow.