1. (1929) Frank Griffin discovered DNA
ITS HISTORY
(1929) Frank Griffin discovered DNA
(1952) Rosalind Franklin took X-rays of DNA. She was assisted by Maurice Wilkins
Rosalind Franklin
Maurice Wilkins

2.                                                                                                                         
      
                                         
(1962) Nobel Prize went to Watson, Crick & Wilkinshttp:// NQTE

3. The structure of a molecule is related to its function, so knowing what a molecule looks like gives researchers insight into how the molecule works.
DNA is composed of nucleotides

4. Nucleotides have 3 components:
five-carbon sugar
A phosphate group
A nitrogenous base
DNA has deoxyribose for its 5-Carbon Sugar, and the four nitrogenous bases:
adenine (A), guanine (G), cytosine (C), and thymine (T)

5. DNA Nucleotide Thymine Adenine Guanine Cytosine Weak Hydrogen Bonds
Deoxyribose
Sugar
Thymine
Adenine
Sugar
Phosphate
Phosphate
Sugar
Guanine
Sugar
Cytosine
Phosphate
Weak Hydrogen Bonds
Phosphate
Strong Bonds
Sugar
Guanine
Cytosine
Sugar
Phosphate
Phosphate
Thymine
Sugar
Sugar
Adenine

6. Adenine Cytosine Guanine Thymine
Purines (larger than pyrimidines) Pyrimidines
Adenine Cytosine
Guanine Thymine

7. The structure of DNA is double stranded and in the shape of a double helix (twisted ladder)
Backbone of DNA : Sugar & Phosphate (strong chemical bonds)
Rungs of DNA: Nitrogenous Bases (weak chemical bonds)

8. Each base pair of DNA consists of a purine and a pyrimidine
Each base pair of DNA consists of a purine and a pyrimidine Complementary Base Pairs:
Adenine: Thymine
Guanine: Cytosine

9. DNA Replication = The process by which DNA is copied .
Enzymes break apart weak H-bonds, splitting the 2 strands of DNA
Free nucleotides in the nucleus bond with complementary base pairs
Bonds form between the sugars and phosphates to build a new backbone. 2 complete strands of DNA are formed.

10. -G-C-
-T-A-
-A-T-
-C-G-
-G C-
-T A-
-A T-
-G C-
-T A-
-G C-
-T A-
-A T-
-A T-
-G C-
-T A-
C G
A T
T A
T A
C G
A T
DNA polymerase
Add the missing bases

11. Protein Synthesis
Genes are sequences of DNA bases that can be translated into proteins or parts of proteins when they are activated.
Protein has a role in every activity of every organism.
Proteins are made in a process called Protein synthesis.

12. DNA is the template for making proteins
DNA is the template for making proteins. RNA is another nucleic acid that DNA works with.

13. Its Goal: To make proteins mRNA, tRNA, rRNA
RNA – Ribonucleic Acid
RNA is the nucleic acid that acts as a messenger between DNA and the ribosomes.
Its Goal: To make proteins
The different forms of RNA Are:
mRNA, tRNA, rRNA

14. Structure of RNA ( similar to DNA) 1. Sugar (Ribose)
2. Phosphate Group
3. Nitrogen Bases
adenine: uracil(not thymine)
cytosine: guanine
Make up its backbone
Made up of nucleotides
RNA is single stranded

15. There are 3 types of RNA:
1. messenger RNA (mRNA), Carries coded instructions for protein synthesis. It is created from DNA during transcription
2. transfer RNA (tRNA), Brings amino acids to the ribosome in the correct order to build new proteins during translation.
3. ribosomal RNA (rRNA) – Makes up the ribosome with other proteins

16. Ribosomal RNA (rRNA) – A type of RNA that binds to the mRNA and uses the instructions to assemble the amino acids in the correct order

17. Transfer RNA (tRNA) – A type of RNA that delivers amino acids to the ribosome to be assembled into a protein.

18. Transcription: process where enzymes make an RNA copy of a portion of a DNA strand. The information of DNA is now able to leave the nucleus
The process is performed by messenger RNA or mRNA

19. RNA
DNA
Single-stranded
Double-stranded
Base pairs: C-G, A-U
Base pairs: C-G, A-T
(CytosineGuanine Adenine-Uracil)
(Cytosine-Guanine
Adenine-Thymine)
Ribose sugar group
Deoxyribose sugar group

20. STAGE 1 OF PROTEIN SYNTHESIS
Transcription is the process by which information is copied from DNA into a strand of messenger RNA (mRNA). The transfer of information from DNA to RNA. mRNA is manufactured during Transcription.
A region of 2 DNA strands unwinds & separates.
RNA polymerase(enzyme) binds complementary RNA bases to the DNA strands until DNA signals a end to mRNA

21. The enzyme, RNA polymerase, separates. the double strands of DNA and
The enzyme, RNA polymerase, separates the double strands of DNA and complementary nitrogen bases of RNA attach.
RNA polymerase
DNA
T C G C A C G T
A G C G U G C A A
mRNA G C G T G C A

22. STAGE 2 OF PROTEIN SYNTHESIS
Translation is the process by which the information from nucleic acids is coded for amino acids

23. PROTEIN SYNTHESIS 1. mRNA is transcribed from DN A (transcription)
2. mRNA leaves the nucleus and enters the cytoplasm.
3. In prokaryotic cells (which do not have a nucleus) the mRNA travels straight to a ribosome where transcription and translation happen at the same time. Therefore, prokaryotes (bacteria) can reproduce quickly.

24. 4. In eukaryotic cells, RNA splicing occurs
4. In eukaryotic cells, RNA splicing occurs. Introns ( sections of DNA that don’t code for a protein) are cut out and Exons (sections of DNA that do code for proteins) are joined together. RNA splicing controls the genetic information that leaves the nucleus.
5. mRNA moves to and attaches to a ribosome which is free floating in the cytoplasm or attached to endoplasmic reticulum.

25. 6. Translation now occurs.
7. a tRNA molecule bonds with the correct amino acid
8. The tRNA transfers(or carries) the correct amino acid to the ribosome

26. 9. The tRNA with the anticodon (sequence of 3 tRNA bases that complement an RNA codon) attaches to the start codon (sequence 3 mRNA complementary bases to the anticodon) of a mRNA molecule
a. Start Codon is AUG which codes for the amino acid, methionine
b. Stop Codons are UAA, UAG, UGA. These give the signal to stop the synthesis of a protein.

28. 10. Most codons carry a code for a specific amino acid and therefore, the tRNA delivers the amino acids in the correct order.
11. The Ribosome moves along the mRNA and adds more amino acids to the protein as it passes each codon.
12. When the ribosome gets to the stop codon, it falls off the mRNA
13. The completed protein is released and is ready for use.

29. The role of transfer RNA
Ribosome
mRNA codon
Section 11.2 Summary – pages

31. Proteins and Cell Function
When genes are changed, the proteins they code for may change. Changes in proteins can affect cell structure and function.
All of your cells have the same genes – but they don’t all produce the same proteins. Why?

32. There are control mechanisms that “turn on” or “turn off” genes depending on specific environmental factors.
An activated gene is “turned on” and will make a specific protein.
A deactivated gene is “turned off” and will not make a protein, the gene is not expressed
In prokaryotes, genes turn on and off primarily in response to changes in environmental factors.

33. In multicellular eukaryotes , gene regulation often involves several rather complex system. They have many cells with many structures and functions known as cell specialization. Cell specialization can be controlled through selective gene expression, where there is selective activation of different genes. Cell specialization and gene expression can also be contolled in eukaryotes by RNA splicing, in which exons are assembled before leaving the nucleus.

34. In 1961, François Jacob and Jacques Monod proposed a hypothesis to describe how gene expression is controlled in bacteria by proteins that “turn off” genes.

35. Basically there are repressor proteins that binds to DNA to block protein synthesis.
The repressor protein binds to DNA, blocking the binding site of the RNA polymerase and transcription is prevented.
The promoter is a section of DNA that serves as the binding site for the enzyme RNA polymerase. The repressor blocks RNA polymerase from binding to the promoter.

36. When E.coli is in a lactose-rich environment, lactose binds to the repressor protein, changing its shape so it can no longer bind to DNA and this enables the RNA polymerase to bind with the promoter and make enzymes to digest lactose.

37. When the lactose is used up, the repressor protein is free to bind with DNA and the making of RNA is stopped. E. coli stops making the lactose enzymes.

38. Normally the repressors are inactive (not bound to DNA) so the genes are on. High levels of the protein can activate the repressors, causing them to bind to the DNA and prevent protein synthesis. Once levels of the protein are normal, the repressors are again inactivated.

39. GENETIC ENGINEERING
Genetic Engineering refers to any technique used to identify or change genes at the molecular level.

40. Gel Electrophoresis - a process used by researchers to sort large molecules by size. DNA is cut into fragments before gel electrophoresis

41. Restriction enzymes are proteins that break DNA bonds in specific ways at precise base pairs sequences.

42. For example: A restriction enzyme recognizes the six-base sequence GAATTC. It cuts between the G and A.
GAATTC
CTTAAG
The ends of the “cut DNA include several unpaired nucleotides. These ends are called sticky ends because they are open to new bonds.

43. During gel electrophoresis the DNA fragments are dropped into thin slits that have been cut in a track of gel. The gel has a positive charge at one end and a negative charge at the other end. DNA has a negative charge, so the DNA fragments move toward the positive end of the gel. The smallest fragments move farthest.

44. The pattern of bands obtained from gel electrophoresis is called a DNA fingerprint. Everyone’s DNA has a unique pattern.
Gel electrophoresis can be used for identification purposes, to identify if a person carries a gene for a disorder, and to identify the base sequence of all the DNA in every human chromosome like in the Human Genome Project.

45. HUMAN GENOME PROJECT
Goal: to map the 80,000 genes on the 46 human chromosomes.
Began in 1987
Completed in year 2000 by Craig Ventor

46. Stem cells are cells that lack differentiation; therefore they can be used to make replacements of cells or organs needed.
What are stem cells?
Stem Cells Spinal Chord Therapy

49. Recombinant DNA – Altering genomes by combining DNA from the genes of different organisms. DNA with components from different organisms by transferring genes from one organism into the cells of another organism.

50. For example: yeast or bacteria can use the human gene to mass-produce human proteins. This way, human genes are cloned ( using genetic engineering to make copies of genes). Genes are transferred into the yeast or bacteria and the genes are copied by the organism’s cells along with its own chromosomes.

51. To transfer DNA into a cell, a vector ( a carrier of genetic material) is used. A bacterial plasmid can be used as a vector. Plasmids are small circular pieces of DNA. Viruses are also used as vectors.

52. Transgenic Organisms- organisms that contain functional recombinant DNA

54. GENE CLONING
A plasmid is removed from a bacterial cell (cut with restriction enzymes).
DNA is removed from a human cell
The DNA is snipped (making sticky ends) for insertion into the plasmid

55. The plasmid is snipped to make a place to insert the human DNA
The plasmid is snipped to make a place to insert the human DNA. (The human DNA is combined with the plasmid DNA)
A recombinant DNA plasmid is formed
The recombined plasmid is inserted into a bacterial cell
Bacteria reproduce with the human DNA in it (for example: making clones of the human insulin gene.)

56. Gene Splicing – rejoining of DNA fragments
Clones-genetically identical copies
Cloning animals – Ex: Dolly the sheep (Scotland 1997) after 277 attempts
Benefits- to produce healthy, productive animals

57. Sequencing DNA – method used to determine the order of DNA nucleotides
Resurrecting the Extinct