1. WARM-UP: What does DNA stand for. What is the purpose of DNA
WARM-UP: What does DNA stand for? What is the purpose of DNA? What is the structure of DNA and who figured it out?

2. DNA

3. CA Biology Standard- Genetics
4. Genes are a set of instructions encoded in the DNA sequence of each organism that specify the sequence of amino acids in proteins characteristic of that organism. As a basis for understanding this concept:
a. Students know the general pathway by which ribosomes synthesize proteins, using tRNAs to translate genetic information in mRNA.
b. Students know how to apply the genetic coding rules to predict the sequence of amino acids from a sequence of codons in RNA.
c. Students know how mutations in the DNA sequence of a gene may or may not affect the expression of the gene or the sequence of amino acids in an encoded protein.

4. What is DNA?
DNA (Deoxyribonucleic acid) is the molecule that contains the genes of living things.
It is in chromosomes inside the nucleus of eukaryotic cells. (In prokaryotes, it is free-floating in the cytoplasm.)

5. Animation: Human to DNA

7. Rosalind Franklin
In the 1950’s she used X-Ray Diffraction to take a picture of the DNA molecule (long-ways).

8. What does Rosalind Franklin’s picture of DNA show?
There are 2 strands.
The strands are twisted around each other in a double helix.
Nitrogenous bases are at the center of the molecule.

9. James Watson and Francis Crick
They were working on figuring out the structure of DNA but couldn’t figure it out…
When they saw Rosalind Franklin’s Picture of DNA, they figured out that it was a…..
DOUBLE HELIX!

10. What is the structure of DNA?
DNA is a double helix.
The double helix is wound around proteins called histones.
This forms a beadlike structure called a nucleosome.
All packed together, this is chromatin.
Chromatin winds together to form chromosomes.

11. Where is the …. Double helix? Histone? Nucleosome? Chromatin?
Chromosome?

12. DNA Structure

13. What is the structure of DNA?
Double helical ladder
‘Backbone’ of ladder is made of the sugar….
Deoxyribose
And…
Phosphate!

14. What is the structure of DNA?
The ‘rungs’ of the ladder are made of nitrogenous bases …
Pyrimidines (single ring):
Thymine [T] and…
Cytosine [C]
Purines (double ring):
Adenine [A]
Guanine [G]
The purines and pyrimidines are held together by hydrogen bonds.

15. What is the structure of DNA?
A deoxyribose sugar, a phosphate and a base all together make up a…
NUCLEOTIDE!

16. Build a DNA Model in Your Notebook
10 points Cut out the nucleotides and match them up. Paste the pieces of DNA into your notebook. Answer the questions.
Period 2,4 stopped here 4/22/11

17. “Row, Row, Row DNA”
We love DNA Made of nucleotides. Sugar, phosphate and a base Bonded down one side.
Adenine and thymine Make a lovely pair. Cytosine without guanine Would feel very bare.

18. Chargoff’s Rules
He found that the percentage of thymine was about equal to the percentage of adenine.
And the percentage of guanine was about equal to the percentage of cytosine.
Thus, they always pair with each other!

19. CHARGOFF’s RULE = BASE PAIRING RULE!
Thymine always pairs with Adenine
T-A
A-T
Cytosine always pairs with Guanine
C-G
G-C

20. Build a DNA Molecule

21. Why would DNA need to replicate itself?

22. Why would DNA need to replicate itself?
When a cell divides and replicates itself during mitosis, it needs to also replicate its DNA.
During meiosis, the process of gamete formation, DNA needs to be replicated to pass genes onto offspring.

23. DNA Replication Overview
The DNA molecule separates into 2 strands and then produces 2 new complementary daughter strands using the base-pair rule. Each strand of the double helix is a template for the new strand.
Period 0, 1 stopped here 12/1/10

24. DNA Replication
The enzyme Helicase ‘unzips’ the double helix by breaking the hydrogen bonds.
The enzyme DNA Polymerase joins individual nucleotides together, making the new strand of DNA.

25. DNA Replication Animation

26. Paste the DNA strand into your notebook and write the complementary strand.
ATGGGCCTTAAACATTA

27. What is the difference between DNA and RNA?

28. DNA RNA Structure Function/Processes Nitrogenous Bases Type of Sugar
Location in Cell
Types

29. DNA RNA 2-stranded double helix Contains genes/instructions for cell
Structure
2-stranded double helix
Function/Processes
Contains genes/instructions for cell
Nitrogenous Bases
Adenine, thymine, cytosine, guanine
Type of Sugar
Deoxyribose
Location in Cell
Nucleus
Types
n/a

30. What is RNA? Ribonucleic acid
Contains sugar ribose (rather than deoxyribose)
Is single-stranded rather than a double helix
Contains adenine, cytosine, guanine and the base uracil rather than thymine

31. What is the function of RNA?
RNA is involved in protein synthesis  making a gene into a trait!
It takes a copy of DNA out of the nucleus (because DNA is too big to leave the nuclear pores) and functions as a ‘working copy’ of DNA.

32. Types of RNA
Messenger RNA [mRNA]: RNA that makes a copy of DNA and leaves the nucleus
Ribosomal RNA [rRNA]: part of a ribosome, where protein synthesis occurs
Transfer RNA [tRNA]: transfers amino acid to the ribosome as it is needed in the construction of a protein

33. Types of RNA

34. DNA RNA tRNA, mRNA, rRNA Single stranded Involved in protein synthesis
Structure
2-stranded double helix
Single stranded
Function/Processes
Contains genes/instructions for cell
Involved in protein synthesis
Nitrogenous Bases
Adenine, thymine, cytosine, guanine
Adenine, uracil, cytosine, guanine
Type of Sugar
Deoxyribose
Ribose
Location in Cell
Nucleus
Nucleus (mRNA), ribosome and cytoplasm (tRNA & rRNA)
Types
n/a
tRNA, mRNA, rRNA
Period 2 stopped here 10/19/10

35. HOW DO GENES BECOME TRAITS?
PROTEIN SYNTHESIS (GENE EXPRESSION)
TRANSCRIPTION
TRANSLATION

37. Transcription
The process where mRNA molecules are produced by copying part of the DNA molecule into a complementary sequence

39. How does transcription work?
RNA polymerase binds to DNA and separates the strands. It then uses one strand of DNA as a template to assemble an RNA strand.
RNA polymerase only binds to regions of DNA called promoters, areas with specific DNA base sequences.

40. RNA Editing Introns: sequences of DNA that do not code for a gene
Exons: sequences of DNA that DO code for a gene
When mRNA is created, the introns are cut out of it and only the exons are kept!

42. Translation
The process where the cell uses mRNA to produce proteins. tRNA brings amino acids to the ribosome to match up with the mRNA.

44. The Genetic Code
Codon: 3 nucleotide bases that code for a particular amino acid
(1 codon = 1 amino acid).
AUG is the start codon.
3 stop codons: UGA, UAA, UAG.
Only 4 bases, but they code for 20 different amino acids (protein sub-units)
HOW?
4x4x4= 64 possibilities
Period 4 stopped here on 10/28/10

45. How does translation work?
After transcription, mRNA attaches to the ribosome.

46. How does translation work?
2. Starting with the start codon, AUG, in the mRNA the proper amino acid is brought to the ribosome by tRNA. That amino acid is attached to the polypeptide chain. Each tRNA molecule is specific to an amino acid. It has an anticodon that is complementary to the mRNA codon.

48. How does translation work?
Polypeptide bonds are created between amino acids, while bonds between tRNA and the amino acid are broken.
The process continues until tRNA hits a stop codon and the protein is assembled!

50. Protein Synthesis Wksht
15 points REMEMBER: mRNA codes for amino acids using codons. tRNA brings the amino acids to mRNA using anti-codons

51. Central Dogma Sing Along!

52. What is a mutation?

53. Mutations = changes in genetic material
Mutations can be:
Advantageous
Deleterious
Have no effect
Mutations are usually random and spontaneous, but they are sometimes caused by mutagens, chemical or physical agents that cause mutations.

54. Types of Mutagens Chemical Mutagens Physical Mutagens
Example: nicotine, smoke, pesticides, methane, pollution
Physical Mutagens
Ultraviolet rays, radiation, extreme heat
Biological Mutagens
Bacteria, viruses

55. Mutagens
Mutagens that cause cancer are called carcinogens because they cause unregulated cell growth.
Examples of carcinogens:
Poisons
Smoke in your lungs
Pollution
Radiation

56. Types of Mutations
What is the difference between these two statements?
My dog bit the cat.
My dog bit the car.
This is a point mutation- a mutation involving changes in one or a few nucleotides.
Types of Point Mutations:
Insertion
Deletion
Substitution

58. Frameshift mutations are…
When nucleotides are added or deleted, causing the whole reading frame to be shifted so that every amino acid is altered.

59. Gene Action/Mutations
15 points Staple into notebook when finished.

60. Translating a DNA Message

61. Make a DNA Keychain Write a Key in your notebook.
Phosphate = big gold bead
Sugar = big green bead
Adenine = silver tube bead
Thymine = red tube bead
Guanine = dark blue tube bead
Cytosine = green tube bead

62. Instructions for DNA Keychains