1. Unit 6: Protein Synthesis and Genetic Mutations

2. LEQ – Explain the process of protein synthesis.

3. Bell Ringer – ANSWER, DON’T WRITE QUESTION
Look at the your peers sitting around you. Each of you have different colored hair, eyes, height, etc. Brainstorm why you have one color hair, but the person next to you is different. How did this happen?

4. History of DNA Discovery
Griffith (1928)
Showed hereditary material can pass from one bacterial cell to another - transformation
Avery (1940’s)
Wanted to determine if transforming material was protein or DNA
Hershey-Chase Experiment (1952)
Confirmed DNA was hereditary material, not protein

5. History of DNA Discovery
Watson and Crick
Created DNA model
Double Helix!
Won Nobel Prize in 1962 for contribution to molecular structure of DNA

6. Quick Review
Write down one scientist and their contribution towards DNA discovery.

7. DNA Structure DNA Nucleotides
1. Two nucleotide strands wrap around each other in the shape of a double helix
2. 5-carbon deoxyribose sugar
3. Phosphate group
4. One of four nitrogenous bases:
a. Adenine (A)
b. Guanine (G)
c. Cytosine (C)
d. Thymine (T)

8. DNA Structure Purine Pyrimidine
a. Double ringed base
b. Adenine and Guanine
Pyrimidine
a. Single ringed base
b. Cytosine and Thymine
Purines must pair with Pyrimidines so the helix can be made (it can twist)
Sequencing runs from 5’ to 3’ direction
a. Run in antiparallel direction

9. DNA Structure Bonds hold DNA nucleotides together Complementary Bases
Nucleotides along each DNA strand are linked by covalent bonds
Complementary nitrogenous bases are bonded by hydrogen bonds
Complementary Bases
1. H-bonds between N-bases
2. A-T
3. C-G
4. Holds DNA strands together

10. Quick Review: Write response below
Next to each nitrogenous bases, write its complementary base
A  ________
C  ________
T  ________
G  _______
What type of bond holds the backbone together?
What type of bond holds the nitrogen bases together?
Write down the purines within DNA.
Write down the pyrimidines within DNA.

11. DNA Replication Occurs during S-phase of interphase
Process by which DNA is copied in a cell before the cell divides
Results in 2 DNA molecules (1 old and 1 new strand mixed)
Semi-Conservative!
Steps of DNA Replication
1. Begins with the separation of the DNA strands by helicases
a. DNA Helicase - Enzyme untwists DNA and starts replication process
b. H-bonds broken between bases
2. DNA polymerases form new strands by adding complementary nucleotides to each of the original strands
a. DNA polymerase – enzyme responsible for attaching nucleotides in correct order

12. DNA Replication

13. DNA Replication
Replication forks – “Y” shaped region that results when the DNA strands separate
1. Speed up replication process

14. Quick Review: Write response below
Explain how the roles of DNA helicase and DNA polymerase differ during replication.

15. Bodies  Cells  DNA Bodies are made up of cells
All cells run on a set of instructions spelled out in DNA

16. DNA  Cells  Bodies How does DNA code for cells & bodies?
how are cells and bodies made from the instructions in DNA

17. DNA  Proteins  Cells  Bodies
DNA has the information to build proteins
genes
proteins
cells
DNA gets all the glory, Proteins do all the work
bodies

18. How do proteins do all the work
proteins run living organisms
enzymes
control all chemical reactions in living organisms
structure
all living organisms are built out of proteins

19. Cell organization DNA DNA is in the nucleus
genes = instructions for making proteins
want to keep it there = protected
“locked in the vault”
cytoplasm
nucleus

20. Cell organization Proteins chains of amino acids
made by a “protein factory” in cytoplasm
protein factory = ribosome
cytoplasm
nucleus
build proteins
ribosome

21. Passing on DNA information
Need to get DNA gene information from nucleus to cytoplasm
need a copy of DNA
messenger RNA
cytoplasm
nucleus
build proteins
mRNA
ribosome

22. From nucleus to cytoplasm
transcription
DNA
mRNA
protein
translation
trait
nucleus
cytoplasm

23. DNA vs. RNA DNA RNA deoxyribose sugar nitrogen bases double stranded
G, C, A, T
T : A
C : G
double stranded
RNA
ribose sugar
nitrogen bases
G, C, A, U
U : A
C : G
single stranded

24. Quick Review
Write down two differences between DNA and RNA.

25. Transcription Making mRNA from DNA
DNA strand is the template (pattern)
match bases
U : A
G : C
Enzyme
RNA polymerase

26. Matching bases of DNA & RNA
Double stranded DNA unzips T G G T A C A G C T A G T C A T C G T A C C G T

27. Matching bases of DNA & RNA
Double stranded DNA unzips T G G T A C A G C T A G T C A T C G T A C C G T

28. Matching bases of DNA & RNA
Match RNA bases to DNA bases on one of the DNA strands C U G A G U G U C U G C A A C U A A G C
RNA
polymerase U A G A C C T G G T A C A G C T A G T C A T C G T A C C G T

29. Matching bases of DNA & RNA
U instead of T is matched to A
TACGCACATTTACGTACGCGG
DNA
AUGCGUGUAAAUGCAUGCGCC
mRNA
ribosome U C A G

30. cytoplasm
protein
nucleus
ribosome U C A G
trait

31. How does mRNA code for proteins
mRNA leaves nucleus
mRNA goes to ribosomes in cytoplasm
Proteins built from instructions on mRNA
mRNA U C A G aa

32. How does mRNA code for proteins?
TACGCACATTTACGTACGCGG
DNA
ribosome
AUGCGUGUAAAUGCAUGCGCC
mRNA ?
Met Arg Val Asn Ala Cys Ala
protein aa
How can you code for 20 amino acids with only 4 DNA bases (A,U,G,C)?

33. mRNA codes for proteins in triplets
TACGCACATTTACGTACGCGG
DNA
codon
ribosome
AUGCGUGUAAAUGCAUGCGCC
mRNA
AUGCGUGUAAAUGCAUGCGCC
mRNA ?
Met Arg Val Asn Ala Cys Ala
protein
Codon = block of 3 mRNA bases

34. The mRNA code For ALL life! Code has duplicates Start codon
strongest support for a common origin for all life
Code has duplicates
several codons for each amino acid
mutation insurance!
Strong evidence for a single origin in evolutionary theory.
Start codon
AUG
methionine
Stop codons
UGA, UAA, UAG

35. How are the codons matched to amino acids?
TACGCACATTTACGTACGCGG
DNA
AUGCGUGUAAAUGCAUGCGCC
mRNA
codon
UAC
Met
GCA
Arg
tRNA
CAU
Val
anti-codon
amino acid
Anti-codon = block of 3 tRNA bases

36. mRNA to protein = Translation
The working instructions  mRNA
The reader  ribosome
The transporter  transfer RNA (tRNA)
ribosome
mRNA U C A G aa
tRNA G U aa
tRNA U A C aa
tRNA G A C
tRNA aa A G U

37. DNA mRNA protein trait From gene to protein tRNA transcriptionaa
transcription
translation
DNA
mRNA
protein
ribosome U C A G
tRNA aa
trait
nucleus
cytoplasm

38. cytoplasm
protein
transcription
translation
nucleus
trait

39. From gene to protein
protein
transcription
translation

40. Quick Review
Write down 2 key differences between transcription and translation.

41. Protein Function
Proteins determine appearance and functioning of the cell and of the whole organism
Make:
1. Hair
2. Nails
3. Help create muscle
4. Enzymes
5. Cell transport molecules
6. Hormones
7. Antibodies
8. ETC!

42. We made a protein! Where does it go now?
If proteins are translated by ribosomes in cytoplasm  stay in cytoplasm
Proteins made by ribosomes in Rough ER:
1. Goes into ER
2. Protein sequence tells ER where to send it
3. Packaged into vesicles
4. Vesicles move from ER to Golgi  modified here
5. Proteins go to plasma membrane
a. Secreted or remain as membrane proteins

43. Transcription/Translation in All Organisms
Processes are similar in ALL organisms
Key difference:
Prokaryotes don’t have a nucleus
a. Transcription and translation occur in cytoplasm!
b. How is this different from eukaryotes?

44. Quick Review: Write response on separate sheet of paper.
Word splash  Explain the transport of a protein after it has been created using the following words.
Ribosomes
Rough ER
Golgi apparatus
Protein
Vesicle
Plasma membrane
Cytoplasm

45. Bell Ringer
The Umpa Lumpas on Willy Wonka are classified as having what type of condition? What do you guess would have to happen to a person’s genetic make-up to cause this to happen – do you predict a major change or minor change to the DNA?

46. LEQ - Explain how genetic information is expressed and could lead to genetic mutations.

47. Mutations Changes to DNA

48. Mutations Changes to DNA are called mutations change the DNA
changes the mRNA
may change protein
may change trait
DNA
TACGCACATTTACGTACG
mRNA
AUGCGUGUAAAUGCAUGC aa
protein
trait

49. Types of mutations Changes to the letters (A,C,T,G bases) in the DNA
point mutation
change to ONE letter (base) in the DNA
may cause change to protein, may not
frameshift mutation
addition of a new letter (base) in the DNA sequence
deletion of a letter (base) in the DNA
both of these shift the DNA so it changes how the codons are read
big changes to protein!

50. Does this change the sentence?
Point Mutations
One base change
can change the meaning of the whole protein
THEFATCATANDTHEREDRATRAN
Does this change the sentence?
A LITTLE!
THEFATCARANDTHEREDRATRAN OR
THEFATCATENDTHEREDRATRAN

51. Does this change the protein?
Point Mutations
Missense mutation = changes amino acid
Ex. Achondroplasia (dwarfism)
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Does this change the protein?
DEPENDS…
AUGCGUGUAUACGUAUGCGAGUGA
MetArgValTyrValCysGluStop

52. Missense - Sickle cell anemia
Hemoglobin protein in red blood cells
strikes 1 out of 400 African Americans
limits activity, painful & may die young
Normal round cells
Misshapen sickle cells
Only 1 out of 146 amino acids

53. The code has repeats in it! Does this change the protein?
Point Mutations
Silent mutation = no change to protein
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
The code has repeats in it!
Does this change the protein?
Why not?
AUGCGUGUAUACGCUUGCGAGUGA
MetArgValTyrAlaCysGluStop

54. Really destroyed that protein!
Point Mutations
Nonsense mutation = change to STOP
Ex. Muscular dystrophy
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Really destroyed that protein!
AUGCGUGUAUAAGCAUGCGAGUGA
MetArgValStop

55. Does this change the sentence?
Frameshift Mutations
Add or delete one or more bases
changes the meaning of the whole protein
THEFATCATANDTHEREDRATRAN
Does this change the sentence?
A LOT!
Delete one!
Add one!
THEFATCANTANDTHEREDRATRAN OR
THEFATCAANDTHEREDRATRAN

56. Does this change the protein?
Frameshift Mutations
Insertion = add one or more bases
Ex, Crohn’s disease
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Does this change the protein?
A LOT!
AUGCGUGUAUACGUCAUGCGAGUGA
MetArgValTyrValMetArgValA

57. Does this change the protein?
Frameshift Mutations
Deletion = lose one or more bases
Ex. Cystic Fibrosis
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
Does this change the protein?
A LOT!
AUGCGUGUAUACGAUGCGAGUGA
MetArgValTyrAspAlaSerGA

58. Cystic fibrosis Broken salt channel in cells
strikes 1 in 2500 white births
gene codes for a protein channel that allows salt to flow across cell membrane
broken protein doesn’t work as channel
doesn’t allow salt out of cell, so water doesn’t flow out either
thicker & stickier mucus coating around cells
mucus build-ups in lungs & causes bacterial infections
destroys lung function
without treatment children die before 5; with treatment can live past their late 20s
Cystic fibrosis is an inherited disease that is relatively common in the U.S. Cystic fibrosis affects multiple parts of the body including the pancreas, the sweat glands, and the lungs. When someone has cystic fibrosis, they often have lots of lung problems. The cause of their lung problems is directly related to basic problems with diffusion and osmosis in the large airways of the lungs.
People without cystic fibrosis have a small layer of salt water in the large airways of their lungs. This layer of salt water is under the mucus layer which lines the airways. The mucus layer in the airways helps to clear dust and other inhaled particles from the lungs.

59. mucus & bacteria build up = lung infections & damage
Salt channel
transports salt through protein channel out of cell
Osmosis problems!
Effect on Lungs
normal lungs
airway
salt
salt channel
normal mucus
H2O
cells lining lungs
cystic fibrosis
salt 
thick mucus
H2O
In people without cystic fibrosis, working cystic fibrosis proteins allow salt (chloride) to enter the air space and water follows by osmosis. The mucus layer is dilute and not very sticky.
In people with cystic fibrosis, non-working cystic fibrosis proteins mean no salt (chloride) enters the air space and water doesn't either. The mucus layer is concentrated and very sticky.
People with cystic fibrosis have lung problems because:
Proteins for diffusion of salt into the airways don't work. (less diffusion)
Less salt in the airways means less water in the airways. (less osmosis)
Less water in the airways means mucus layer is very sticky (viscous).
Sticky mucus cannot be easily moved to clear particles from the lungs.
Sticky mucus traps bacteria and causes more lung infections.
Therefore, because of less diffusion of salt and less osmosis of water, people with cystic fibrosis have too much sticky mucus in the airways of their lungs and get lots of lung infections. Thus, they are sick a lot.
mucus & bacteria build up = lung infections & damage

60. Deletion leads to Cystic fibrosis
Loss of one
amino acid!

61. Quick Review
Differentiate one key difference between point and frameshift mutations.
Which types of point mutations typically create a nonfunctional protein?
Take the following sentence and convert it to a deletion frameshift mutation:
She hit the box.