1. Deoxyribonucleic Acid
DNA
Deoxyribonucleic Acid

2. DNA is our genetic code.
DNA is located in the nucleus of every living cell in our bodies.

3. DNA is made up of smaller units called nucleotides.
Nucleotides make segments on DNA called genes.
Genes control traits that are inherited from parents.

5. Humans have 46 strands of DNA called chromosomes or chromatin.

6. Our chromosomes are arranged in 23 pairs.
KARYOTYPE: Man-made arrangement of all chromosomes in a cell (shown here)

7. We have over 30,000 functional genes located on our 46 chromosomes.

8. For genes to express themselves as a trait, you need a gene pair.
In each pair of chromosomes: 1 came from mom and 1 came from dad.

11. nucleotides  DNA  genes  chromosomes

12. STRUCTURE OF A NUCLEOTIDE
A nucleotide is the simplest monomer of a DNA molecule. It is composed of 3 parts:
1. A phosphate group
2. A deoxyribose sugar
3. A nitrogenous base

16. Nitrogenous Bases Guanine = G Cytosine = C Adenine = A Thymine = T
Uracil = U*
(*Replaces T in RNA only!)

17. Nitrogenous Bases C always pairs with G A always pairs with T*
*In RNA, A always pairs with U
Bases are held together with hydrogen bonds
A T (2 H bonds)
C G (3 H bonds)

18. Chargaff’s Rules Erwin Chargaff, American biochemist
The percentage of Guanine (G) and Cytosine (C) bases are almost equal in any DNA sample.
The same is true for Adenine (A) and Thymine (T) bases.

19. Nitrogenous Bases
Purines—
2 rings (A & G)
Pyridimines—
1 ring (C & T)

21. THE DISCOVERY OF DNA
BACK THEN…
IT WAS A RACE!

22. JAMES WATSON & FRANCIS CRICK

23. February 28, 1953
Watson was only 25 years old!
Crick was 37 years old

26. MAURICE WILKINS & ROSALIND FRANKLIN

28. In 1962, Watson, Crick, and Wilkins were awarded the Nobel Prize for Physiology or Medicine
"for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material“

30. DNA vs. RNA

31. DNA RNA Deoxyribonucleic acid 1. Double helix (larger in size)
1. Single strand (smaller in size)

32. DNA
2. Carries instructions for genetic blueprint (directions for making proteins)
RNA
2. Translates and decodes genetic message and builds proteins

33. DNA RNA 3. Found in the nucleus
4. Sugar = deoxyribose
RNA
3. Found in the nucleus, ribosomes, cytoplasm
4. Sugar = ribose

34. DNA RNA 5. Processes: -replication -transcription 6. 4 nitrogen bases
A, T, C, G
RNA
5. Processes:
-transcription
-translation
6. 4 nitrogen bases
A, U, C, G

35. DNA RNA 7. One type 7. Three types -messenger -ribosomal -transfer
All made from DNA
All have different structures to suit their functions

37. TYPES OF RNA

38. MESSENGER RNA Also called mRNA
Acts as a messenger (carries genetic instructions)
Moves genetic instructions out of nucleus after making a copy
(DNA can’t leave the nucleus!!!)

39. MESSENGER RNA Copy is carried to the ribosome to be translated
Contains special base sequences called CODONS (a code word)
CODON—Series of 3 bases

40. MESSENGER RNA
Shape of mRNA:
Long, linear single strand

41. TRANSFER RNA Also called tRNA Two functions:
Decoder/translator of genetic message
Transports amino acids to ribosome for assemble of protein

42. TRANSFER RNA Has two important binding regions
ANTICODON: sequence of 3 bases on tRNA that must be complementary of mRNA codon)
Attachment site for AMINO ACID to bind

43. TRANSFER RNA Shape of tRNA:
Folded linear molecule, resembles a “t” shape or “cross”

44. RIBOSOMAL RNA Also called rRNA
Site where amino acids are assembled into proteins needed by the cell

45. RIBOSOMAL RNA
Shape of rRNA:
Makes up the structure of the ribosome