1. DNA Deoxyribonucleic Acid

2. DNA: True or False
DNA is found in all living things.
True

3. DNA: True or False
DNA condenses to form chromosomes.
True

4. DNA: True or False DNA replicates during mitosis.
False…DNA replicates during INTERPHASE!

5. DNA: True or False
The human DNA sequence would ONLY fill one 1,000 page phone book.
False…the human DNA sequence would fill 200 phonebooks!!!

6. DNA: True or False
Your DNA sequence is 99.9% the same as the person sitting next to you.
True

7. DNA: True or False
If you stretched the DNA in ONE cell it would reach 6 feet tall.
True

8. DNA: True or False
If you stretched the DNA in ALL of your cells it would reach the moon ONE time.
False…because it would stretch to the moon 6,000 TIMES!!!!

9. DNA: True or False
Parents and children share 50% of their DNA.
True

10. DNA: True or False
Humans and chimpanzees share around 75% of their DNA.
False…Humans and chimpanzees share 94-99% of their DNA.

11. DNA: True or False
It would take a person typing 60 words a minute, 8 hours a day, around 50 years to type the human genome.
True!

12. DNA Structure

13. What is DNA? The information that determines an organism’s traits.
DNA contains a code that produces proteins
Many things contain and are made of proteins.
Skin, hair, bones, etc are made of proteins.

14. What is DNA? Cont’d Enzymes are special proteins.
Enzymes control chemical reactions needed for life.
DNA contains all the information for making all proteins for human life.

15. DNA Structure: DNA is made of repeating subunits called nucleotides.
Nucleotides have three parts:
Simple sugar
Phosphate group
Nitrogen base

16. One Nucleotide
Phosphate Group
Nitrogen Base
Sugar (Deoxyribose)

17. DNA Structure The simple sugar is called deoxyribose.
The phosphate group is made of phosphorus and oxygen.

18. DNA Structure Four possible Nitrogen Bases: Thymine (T) Adenine (A)
Cytosine (C)
Guanine (G)

19. DNA Nucleotides join together to form long chains.
“Backbone”
Nucleotides join together to form long chains.
The phosphate group of one nucleotide joins together with the deoxyribose sugar of an adjacent nucleotide.
“Steps”

20. Adenine & Thymine (A-T)
DNA
Nitrogen bases pair up
Adenine & Thymine (A-T)
Cytosine & Guanine
(C-G)
Complementary bases

21. Watson & Crick, 1953
Proposed DNA is put together like a “twisted zipper”
DNA = 2 chains of nucleotides joined by nitrogen bases

22. Watson & Crick, 1953 Double Helix
Double = DNA has two strands
Helix = twisted like a spring, “spiral”

23. Importance of Sequencing
The sequence of the four different nucleotides determines what organism is created.
For instance: T-A-A-G-C-A is different than A-G-C-A-A-G
Another example: E-A-R-T-H is different than
H-E-A-R-T
vs.

24. Importance of Sequencing
The more similar the order of nucleotides are, the closer the relationship between 2 organisms

25. DNA Replication

26. DNA Replication Replication = to copy
Process of copying DNA in the chromosomes
Without DNA replication, a new cell would only have half of its information.

27. DNA Replication T-A-G-C-C-G-T A-T-C-G-G-C-A
Because of the pairing- if you have one strand, it is easy to predict the replicated strand.
T-A-G-C-C-G-T
Remember: A goes with T, C goes with G
A-T-C-G-G-C-A

28. DNA Replication
Remember: The nitrogen bases are held together by hydrogen bonds
An enzyme (Helicase) goes to those hydrogen bonds and breaks them = Double Helix Unzips

29. DNA Replication Step 1: Separate the two DNA strands
Helicase (enzyme) does this

30. DNA Replication
Step 2: Original DNA strand acts as a template & complementary nucleotides fill in.
Primase(enzyme) finds a starting point to connect
DNA Polymerase(enzyme) does the connecting

31. DNA Replication
Step 3: Nucleotides connect and a new sugar-phosphate “backbone” is formed.

32. DNA Replication
Each new DNA molecule consists of one original strand and one new strand

33. So now what??

34. What’s So Special About Proteins?
DNA encodes the instructions for making proteins.
Remember proteins make up your bones, skin, etc.
Enzymes are special proteins
Enzymes control all chemical reactions in an organism

35. DNA Codes For Proteins Proteins are made up of many amino acids
The order of nucleotides in each gene has information on how to make the string of amino acids which is a protein.
ESTIMATE: Each cell contains about 19,000-22,000 genes

36. We need to figure out how to get from DNA to Proteins!
DNA makes RNA-That's Transcription
RNA makes Protein-That's Translation
RNA makes Protein-That's Translation

37. What is it? What does it do?
RNA
What is it?
What does it do?

38. RNA vs. DNA RNA Single Stranded- only half of a zipper
Contains the sugar Ribose
Contains the nitrogen bases:
Adenine
Uracil
Guanine
Cytosine
DNA
Double Stranded- double helix
Contains the sugar Deoxyribose
Contains the nitrogen bases:
Adenine
Thymine
Guanine
Cytosine

39. RNA It’s job: Copying DNA It’s goal: To create proteins
There are 3 types, each with a different job:
mRNA= Messenger RNA: copies DNA to take it out in the cytoplasm
rRNA= Ribosomal RNA: works on matching mRNA - to create the amino acids in the correct order
tRNA= Transfer RNA: gives amino acids to rRNA to produce the protein.

40. mRNA
Brings information (in the form of an RNA strand) from the DNA in the nucleus to the cytoplasm

41. Ribosomes Where are ribosomes found?
In the Cytoplasm
A ribosome attaches to the mRNA and reads its information to build a chain of amino acids - That creates a PROTEIN
Ribosome
mRNA

42. tRNA
Amino Acid
The supplier
Brings amino acids to the ribosome so that it can assemble the protein

43. Review Questions How is DNA replicated? What are the steps?
What molecule carries information from the nucleus to the cytoplasm?
What organelle reads the information and builds protein?

44. Transcription

45. Transcription
Transcription’s purpose is to create a single stranded RNA molecule rather than a double stranded DNA molecule.
This is needed to allow the single stranded RNA to be taken out of the nucleus by the mRNA to the cytoplasm.

46. Genetic Code with mRNA
In order to take the DNA and create a mRNA, there are special codes used.
In mRNA, three nitrogen bases together form a code – this is called a codon.
Looking ahead:
this code is matched with an amino acid.
A string of amino acids forms a protein.

47. Genetic Code with mRNA Most codons code for amino acids.
Amino acids link together to form a protein.
There are 64 codons – many code for the same amino acid. All are very specific.
AUG is the start codon.
UAG is one of three stop codons.

48. Transcription DNA Unzips at a gene
RNA nucleotides base pair to the DNA template
Finished mRNA detaches and moves to the cytoplasm
Remember: Never T’s your RNA

49. Messenger RNA builds on a DNA template

50. Translation

51. Translation: From mRNA to Protein
The process of changing the information from an order of nitrogen bases in mRNA into the order of amino acids of a protein
Occurs at the ribosome, in the cytoplasm

52. Translation Steps
When mRNA enters the cytoplasm, ribosomes attach to it
20 different amino acids must be brought to the ribosomes for proteins to be made
Transfer RNA’s (tRNA) bring the amino acids to the mRNA strand
The amino acids are joined to make a specific protein

53. Transfer RNA’s (tRNA) Transfer RNA’s (tRNA) carry specific amino acids
Each tRNA has an anticodon of 3 bases
Anticodons and codons are opposites (Complementary)

54. Translation 1
When a match is made between codons and anticodons- a temporary bond is formed.
This places the amino acid in the correct position to enable it to bond with the next amino acid

55. Translation 2
The next tRNA bonds to it’s codon and then the two amino acid’s bond together.
The first amino acid then releases itself from the mRNA

56. Translation This continues until a stop codon is reached.
Amino acid chains then become proteins when they are freed from the ribosome and twist and curl into complex three-dimensional shapes.

57. Translation