1. GENETICS
DNA Basics

2. What are these two creatures? …the mammals.
Which species weighs more? Use your personal technology to find out.

3. What are their scientific names?
Ursus arctos
Ursus maritimus

4. What makes them different?
DNA

5. Distinguish between DNA and RNA
Standard SB2a
Distinguish between DNA and RNA

6. A little history lesson…

8. Rosalind Franklin…

10. And now…the notes.

11. DNA: The Molecule of Heredity
DNA = Deoxyribonucleic acid; a type of nucleic acid
The building blocks (monomers) of DNA are nucleotides
A nucleotide is composed of:
Deoxyribose (a sugar compound)
A phosphate group
A nitrogen base
Ringed compound that contains Nitrogen

12. Nitrogen bases in DNA In DNA, there are four possible Nitrogen bases
Adenine
Guanine
Cytosine
Thymine

13. The Double Helix
The three parts of DNA (sugar, phosphate, and nitrogen base) come together to form NUCLEOTIDES
The nucleotides will link together to form two long strands
The two strands will connect at the nitrogen bases and twist forming a DOUBLE HELIX
The linking occurs with “complimentary base pairing”…
Adenine will pair with Thymine
Guanine will pair with Cytosine
The link that holds the bases together is a Hydrogen bond

14. Let’s Practice…
A-T-C-C-G-A-T-A-C is one strand of a double stranded DNA sequence.
Write the complimentary DNA strand.
A-T-C-C-G-A-T-A-C
║ ║ ║ ║ ║ ║ ║ ║ ║
T-A-G-G-C-T-A-T-G

15. DNA Double Helix

16. Chargaff’s Rule…
Erwin Chargaff (1950) determined that in any strand of DNA:
% purines = % pyrimidines
%A = %T
%C = %G
#A+T ≠ #C+G

17. Practice Problem…
A DNA sample was found to have 24% Adenine. What will be the percentages of Cytosine, Guanine and Thymine in this sample?

18. Practice Problem 2 In a particular sample of DNA, there are 17%G.
Determine the percentages of the other bases in this sample.

19. Practice Problem 3
A sample of DNA taken from a crime scene is found to have 200 base pairs (400 bases). Of the bases, 120 are Thymine.
Determine the numbers and percentages of the other 3 bases.

20. Practice Problem 4
A sample of DNA taken from a recruit at indoc into the Army is found to have 40 base pairs (80 bases). Of the bases, 22 are Guanine.
Determine the numbers and percentages of the other 3 bases.

21. Prokaryotic DNA
The DNA in bacteria is different from the DNA in eukaryotic cells.
In bacteria, the DNA is a single circular strand of DNA.
Kind of looks like “spaghetti-ohs”.

22. RNA vs DNA There are THREE main differences between DNA & RNA
The sugar
In DNA it’s DEOXYribose sugar
In RNA it’s Ribose sugar
Number of strands
DNA is usually double stranded
RNA is ONLY single stranded
Nitrogen Bases
DNA
Adenine pairs with Thymine
Guanine pairs with Cytosine
RNA
Adenine pairs with Uracil

23. Why DNA? Segments of DNA code for proteins
Each set of three base pairs codes for a particular amino acids
The three bases are called the codon
Amino acids are the building blocks for proteins
Since 3 bases pairs are involved, the DNA code is often called the triplet code
There are 64 possible codon combinations given the four nitrogen bases combined into triplets

24. DNA & Chromosomes
When comparing the chromosomes of two different organisms, you’ll find that both contain DNA with the same bases
The ORDER of the nucleotides is what makes the organisms different
The more closely related two organisms are, the more alike their order of nucleotides will be.

25. Genes & Chromosomes Genes Chromosomes
Small pieces of DNA that code for a specific trait
Chromosomes
Collection of genes that are wound in the shape of an X (when ready for cell division)
Half of a chromosome – a chromatid

28. Video…
Bozeman Video…

29. Review: Which of the following is the monomer of DNA?
A.) phosphate group
B.) nucleotide
C.) RNA
D.) deoxyribose

30. B.) nucleotide Review: Which of the following is the monomer of DNA?
A.) phosphate group
B.) nucleotide
C.) RNA
D.) deoxyribose

31. Review Nucleotides are made of: A.) a sugar B.) a phosphate group
C.) a nitrogen base
D.) all of the above

32. D.) all of the above Review Nucleotides are made of: A.) a sugar
B.) a phosphate group
C.) a nitrogen base
D.) all of the above

33. Review The people credited with discovering DNA’s structure are:
A.) Avery and Chase
B.) Mendelsohn and Stahl
C.) Watson and Crick
D.) All of the above

34. C.) Watson and Crick Review
The people credited with discovering DNA’s structure are:
A.) Avery and Chase
B.) Mendelsohn and Stahl
C.) Watson and Crick
D.) All of the above

35. Review Which of the following is not found in DNA? A.) Deoxyribose
B.) Phosphate
C.) Adenine
D.) Protein

36. D.) Protein Review Which of the following is not found in DNA?
A.) Deoxyribose
B.) Phosphate
C.) Adenine
D.) Protein

37. Review The sides (backbone) of DNA are made of:
A.) Deoxyribose sugar and adenine
B.) complete nucleotides
C.) sugar and phosphate
D.) Nitrogen bases, sugar and phosphate

38. C.) sugar and phosphate Review
The sides (backbone) of DNA are made of:
A.) Deoxyribose sugar and adenine
B.) complete nucleotides
C.) sugar and phosphate
D.) Nitrogen bases, sugar and phosphate

39. Review In DNA, Adenine bonds with: A.) Adenine B.) Guanine
C.) Cytosine
D.) Thymine

40. D.) Thymine Review In DNA, Adenine bonds with: A.) Adenine B.) Guanine
C.) Cytosine
D.) Thymine

41. Review What holds one base to another? A.) hydrogen bonds
B.) the sugar
C.) phosphate groups
D.) ionic bonds

42. A.) hydrogen bonds Review What holds one base to another?
B.) the sugar
C.) phosphate groups
D.) ionic bonds

43. Review The following is one side of a DNA strand: A-T-G-T-C-C-A-T
Which of the following would be the complementary (other side of the )DNA strand?
A.) A-T-G-T-C-C-A-T
B.) T-A-C-A-G-G-T-A
C.) T-T-G-G-A-C-A-T
D.) A-A-G-A-G-G-T-A

44. B.) T-A-C-A-G-G-T-A Review
The following is one side of a DNA strand: A-T-G-T-C-C-A-T
Which of the following would be the complementary (other side of the )DNA strand?
A.) A-T-G-T-C-C-A-T
B.) T-A-C-A-G-G-T-A
C.) T-T-G-G-A-C-A-T
D.) A-A-G-A-G-G-T-A

45. Review Which of the following could be a nucleotide of DNA?
A.) Deoxyribose, uracil, phosphate
B.) Ribose, adenine, phosphate
C.) Adenine, Thymine, phosphate
D.) Guanine, phosphate, deoxyribose

46. D.) Guanine, phosphate, deoxyribose
Review
Which of the following could be a nucleotide of DNA?
A.) Deoxyribose, uracil, phosphate
B.) Ribose, adenine, phosphate
C.) Adenine, Thymine, phosphate
D.) Guanine, phosphate, deoxyribose