1. DNA
DNA
CLIP 1

2. DNA Function: Carry genetic material 2 located in the nucleus
Many People contributed to the discovery of DNA. 2

3. People Who Discovered DNA
1928 – Frederick Griffith - DNA = carrier of genetic info
1944 – Avery – Genes = composed of DNA
1952 – Hershey and Chase – genetic material = DNA, not protein 3

4. People Who Discovered DNA
1952 – Rosalind Franklin – DNA = twisted
1952 – Edwin Chargraff - #A = #T; #C = #G; Chargraff’s Rule
1953 – Watson and Crick – Discovered structure of DNA we know today 4

5. What we
Know
Now 5

6. Shape of DNA 6 Double Helix. Two stranded
-Twisted ladder or spiral staircase
Two stranded
Held together by hydrogen bonds
Made of four Nucleotides 6

7. Structure of DNA 7 Remember: DNA is a nucleic acid.
Nucleic acids are made of nucleotides 7

8. Nucleotides DNA = long chain of nucleotides 4 that make up DNA
Have 3 parts: a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base 8

9. 4 NitrogenousBases
Adenine
Guanine
Cytosine
Thymine 9

10. Sides of the “Ladder” are made up of sugar and phosphate.10

11. Adenine always pairs with Thymine Cytosine always pairs with Guanine11

12. Would Thymine be able to pair up with Guanine?
NO!! 12

13. 13

14. DNA
REPLICATION
DNA Replication 20 14

15. DNA Replication
Before mitosis, the DNA must be replicated (Copied) exactly.
Each strand can be used to make the other strand.
Many enzymes are involved. 15

16. Chromosome Structure
DNA is packed very tightly as chromosomes in the nucleus.
Human nucleus has 1 meter of DNA!
Smallest human chromosome has 30 million base pairs. 16

17. Chromosome Structure 17 A chromosome has DNA and protein-chromatin.
Tiny sections of DNA are called genes 17

18. Steps:
parent/original strands are unwound with the help of DNA helicases (enzymes).
Replication Bubble
Semi-conservative replication 18

19. Replpication
Bubbles 19

20. Steps:
2. DNA polymerase attached new nucleotides to the parent strands 20

21. DNA replication website21

22. How a protein is made
Transcription
Translation 22

23. DNA codes for all of the cell proteins.23

24. DNA Transcription 24

25. 25 Overview: DNA is located in the Nucleus
Proteins are made on the ribosomes.
DNA makes a copy (send a message) called “mRNA” 25

26. Two Steps of Protein Synthesis
2. Translation
1. Transcription 26

27. Transcription
a copy of the DNA is made…the copy is called messenger RNA or mRNA.
The mRNA takes the code to the ribosome. 27

28. DNA vs. RNA Single Stranded Double Stranded AGUC AGTC Ribose
YES!
Double Stranded
AGTC
Deoxyribose
NEVER! 28

29. DNA Transcription
During transcription the DNA unzipped and RNA nucleotide are paired up with the DNA bases.
Website 29

30. DNA Translation 30

31. 31

32. Once the mRNA copy is made, it can go to the ribosome to be translated.32

33. 33 Remember….Proteins are made out of amino acids.
There are 20 different amino acids.
3 bases code for each amino acid = codon. 33

34. How you figure out which codon is coding for which amino acid…34

35. Once the mRNA gets to the ribosome, the protein can be assembled.
Transfer RNA brings the amino acids to the ribosome.
Website 35

36. The three letter code on the mRNA is called a codon.
The three letter code on the tRNA that is matched up with the mRNA is called an anticodon. 36

37. Review Clip 37

38. Mutations 38

39. Mutations A sudden change in the genetic code is called a mutation.
Most mutations have little or no effect on the organism.
Mutations can be spontaneous or may be caused by environmental factors called mutagens. 39

40. Mutations in DNA usually occur through one of two processes:
1- DNA damage from environmental agents such as ultraviolet light (sunshine), nuclear radiation or certain chemicals.
2- Errors that occur when a cell replicates its DNA in preparation for cell division. 40

41. Types of Mutations 41

42. -a simple change in a single base of the gene sequence
Point mutation
-a simple change in a single base of the gene sequence
3 Types:
Point
Insertion
Deletion 42

43. Frame-shift Mutations
In a frame-shift mutation, one or more bases are deleted or inserted, the equivalent of adding or removing letters in a sentence.
Original:
THE CAT ATE THE RAT
Deletion:
THE CTA TET HER AT
Insertion
THE CAT ATT ETH ERA T 43

44. DNA Mutations Harmful, Helpful, Neutral
Substitutions
Frameshift
Deletions
Insertions
Causes:
Mutagens
UV light
Radiation
Chemicals (ex: substances in tobacco products)
Replication errors
CLIP 51 44

45. 53 45

46. Which of the following is the correct base-pairing rule for DNA?
A A-U; C-G
B A-G; T-C
C A-T; G-C
D A-C; T-G 46

47. DNA TECHNOLOGY 47 DNA fingerprinting industry agriculture medicine
genetic recombination.
forensics 47

48. DNA Fingerprinting
How they identify criminals and do paternity tests (i.e. “Who is my Baby’s Daddy?”) 48

49. How DNA Fingerprinting works:
Scientist cut up DNA into pieces using enzymes
Then load the pieces into a gel.
Electricity is run through the gel.
The pieces of DNA move to the other end of the gel.
Smaller pieces move farther. 49

50. Who doesn’t belong? 50

51. Recombinant DNA
is a form of artificial DNA where DNA combined that would not normally be combined.
They cut, splice together, and insert the modified DNA molecules from different species into bacteria or another type of cell that rapidly replicates and divides.
The cells copy the foreign DNA right along with their own DNA.
Example: goldfish have genes for fluorescent proteins that have been inserted 51

52. Genetic Engineering 60 52 the manipulation of an organisms genes
applications in medicine and the environment, industry, and agriculture.
Sheep are used in the production of alpha-1 antitrypsin, which is used in the treatment of emphysema.
Goats are also producing the CFTR protein used in the treatment of cystic fibrosis.
Crops are being devised that have natural insect repellants 60 52

53. Genetic Engineering
Example:
In the plant world, the buds of cotton plants are vulnerable to worm attacks. The buds of a modified cotton plant resist these worms, resulting in increased cotton production.
These gene insertions are ecologically safer than pesticides. They affect only the targeted pest. 53

54. 54 Clip Scientists today have developed genetically altered bacteria.
Among them are strains of bacteria that
eat up oil spills
manufacture alcohol and other chemicals
process minerals.
There is concern about possible risks to the environment and the general population as genetically engineered bacteria are introduced. 54

55. 55