Making Sense of DNA. DNA is a code for making proteins DNA (Gene) Protein Trait.
2009-2010 Protein Synthesis Making Proteins DNA Lesson 1.
-
Upload
myron-shelton -
Category
Documents
-
view
227 -
download
3
Transcript of 2009-2010 Protein Synthesis Making Proteins DNA Lesson 1.
2009-2010
Protein Synthesis Making Proteins
DNALesson 1
Bodies are made up of cells All cells run on a set of instructions
spelled out in DNA
Bodies Cells DNA
How does DNA code for cells & bodies? how are cells and bodies made from the
instructions in DNA
DNA Cells Bodies
DNA has the information to build proteins genes
DNA Proteins Cells Bodies
proteinscells
bodiesDNA gets all the glory,Proteins do all the work
How do proteins do all the work
• Proteins– proteins run living organisms– enzymes
• control all chemical reactions in living organisms
– structure• all living organisms are built out of proteins
cytoplasm
nucleus
Cell organization
• DNA– DNA is in the nucleus
• genes = instructions for making proteins
– want to keep it there = protected• “locked in the vault”
Cell organization• Proteins
– chains of amino acids– made by a “protein factory” in cytoplasm– protein factory = ribosome
nucleus
cytoplasm
ribosome
aa
aa
aa
aa
aa
aa
aa
aaaa
aa
buildproteins
In class assignment
• Multiple Choice worksheet
Homework
• Vocab and DNA worksheets
PASSING ON DNALesson 2
Do Now
• BrainPop video: RNA
• Multiple choice worksheet
Passing on DNA information• Need to get DNA gene information
from nucleus to cytoplasm– need a copy of DNA– messenger RNA
nucleus
cytoplasm
ribosome
mRNA
buildproteins
aa
aa
aa
aa
aa
aa
aa
aaaa
aa
mRNA
From nucleus to cytoplasm
DNA
transcription
nucleus cytoplasm
translation
trait
aa
aa
aa
aa
aa
aa
aa
aaaa
aa
protein
DNA vs. RNA
DNA• deoxyribose sugar • nitrogen bases
– 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
Transcription
• Making mRNA from DNA
• DNA strand is the template (pattern)– match bases
• U : A• G : C
• Enzyme– RNA polymerase
Matching bases of DNA & RNA
• Double stranded DNA unzips
A G GGGGGT T A C A C T T T T TC C C CA A
Matching bases of DNA & RNA
• Double stranded DNA unzips
A G GGGGGT T A C A C T T T T TC C C CA A
Matching bases of DNA & RNA
• Match RNA bases to DNA bases on one of the DNA strands
U
A G GGGGGT T A C A C T T T T TC C C CA A
U
UU
U
U
G
G
A
A
A C CRNA
polymerase
C
C
C
C
C
G
G
G
G
A
A
A
AA
Matching bases of DNA & RNA
• U instead of T is matched to A
TACGCACATTTACGTACGCGGDNA
AUGCGUGUAAAUGCAUGCGCCmRNAaa
aa
aa
aa
aa
aa
aa
aaaa
aa
U C CCCCCA A U G U G A A A A AG G G GU Uribosome
In class assignment
• Protein Synthesis1
Homework
• Protein Synthesis Practice 2
MRNA CODESLesson 3
Do Now
• RNA Vocab worksheet
How does mRNA code for proteins
• mRNA leaves nucleus
• mRNA goes to ribosomes in cytoplasm
• Proteins built from instructions on mRNA
aa aa aa aa aa aa aa aa
How?
mRNA
U C CCCCCA A U G U G A A A A AG G G GU U
How does mRNA code for proteins?
TACGCACATTTACGTACGCGGDNA
AUGCGUGUAAAUGCAUGCGCCmRNA
Met Arg Val Asn Ala Cys Alaprotein
?
How can you code for 20 amino acids withonly 4 DNA bases (A,U,G,C)?
ribosome
aa aa aa aa aa aa aa aa
AUGCGUGUAAAUGCAUGCGCCmRNA
mRNA codes for proteins in triplets
TACGCACATTTACGTACGCGGDNA
AUGCGUGUAAAUGCAUGCGCCmRNA
Met Arg Val Asn Ala Cys Alaprotein
?
Codon = block of 3 mRNA bases
ribosome
• For ALL life!– strongest support for a
common origin for all life
• Code has duplicates– several codons for
each amino acid– mutation insurance!
Start codon AUG methionine
Stop codons UGA, UAA, UAG
The mRNA code
How are the codons matched to amino acids?
TACGCACATTTACGTACGCGGDNA
AUGCGUGUAAAUGCAUGCGCCmRNA
anti-codon
codon
tRNAUAC
MetGCA
ArgCAU
Val Anti-codon = block of 3 tRNA bases
aminoacid
mRNA to protein = Translation
• The working instructions mRNA• The reader ribosome• The transporter transfer RNA (tRNA)
mRNAU C CCCCCA A U G U G A A A A AG G G GU U
aaaa
aa
tRNA
GGU
aa
tRNA
U A C
aa
tRNA
GA C
tRNA
aa
A GU
ribosome
aa
aa
aaaa
aa
aa
aa
mRNA
From gene to protein
DNA
transcription
nucleus cytoplasm
protein
translation
trait
U C CCCCCA A U G U G A A A A AG G G GU Uribosome
tRNA
aa
protein
aa
aa
aa
aa
aa
aa
aa
aaaa
aa
aa
transcription
cytoplasm
nucleus
translation
trait
From gene to protein
transcriptiontranscription
translationtranslation
proteinprotein
In class assignment
• Protein Synthesis 3
Homework
• Vocabulary worksheet
PROTEIN SYNTHESIS LABLesson 4
MUTATIONS AND GEL ELECTROPHORESIS
Lesson 5
Do Now
2009-2010
MutationsChanges to DNA
Mutations
• Changes to DNA are called mutations– change the DNA– changes the mRNA– may change protein– may change trait
DNA TACGCACATTTACGTACG
mRNA AUGCGUGUAAAUGCAUGC
aa aa aa aa aa aa aaprotein
trait
Point Mutations
• One base change– can change the meaning of the whole protein
THEFATCATANDTHEREDRATRAN
THEFATCARANDTHEREDRATRAN
THEFATCATENDTHEREDRATRAN
OR
Does this changethe sentence?
A LITTLE!
Frameshift Mutations
• Addition = add one or more bases
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
AUGCGUGUAUACGUCAUGCGAGUGA
MetArgValTyrValMetArgValA
Does this changethe protein?
A LOT!
Frameshift Mutations
• Deletion = lose one or more bases
AUGCGUGUAUACGCAUGCGAGUGA
MetArgValTyrAlaCysGluStop
AUGCGUGUAUACGAUGCGAGUGA
MetArgValTyrAspAlaSerGA
Does this changethe protein?
A LOT!
2006-2007
BiotechnologyGel Electrophoresis
Many uses of restriction enzymes…
• Now that we can cut DNA with restriction enzymes…– we can cut up DNA from different people…
or different organisms… and compare it
– why?• forensics• medical diagnostics• paternity• evolutionary relationships • and more…
Comparing cut up DNA
• How do we compare DNA fragments?– separate fragments by size
• How do we separate DNA fragments?– run it through a gelatin – gel electrophoresis
• How does a gel work?
Gel electrophoresis
• A method of separating DNA in a gelatin-like material using an electrical field– DNA is negatively charged– when it’s in an electrical field
it moves toward the positive side
+–
DNA
“swimming through Jello”
• DNA moves in an electrical field…– so how does that help you compare DNA
fragments?• size of DNA fragment affects how far it travels
– small pieces travel farther
– large pieces travel slower & lag behind
Gel electrophoresis
+–
DNA
“swimming through Jello”
Gel Electrophoresis
longer fragments
shorter fragments
powersource
completed gel
gel
DNA &restriction enzyme
wells
-
+
Running a gel
1 2
cut DNA with restriction enzymes
fragments of DNAseparate out based
on size
3
Stain DNA– ethidium bromide
binds to DNA
– fluoresces under UV light
Uses: Evolutionary relationships
• Comparing DNA samples from different organisms to measure evolutionary relationships
–
+
DNA
1 32 4 5 1 2 3 4 5
turtle snake rat squirrel fruitfly
Uses: Medical diagnostic
• Comparing normal allele to disease allele
chromosome with disease-causing
allele 2
chromosomewith normal
allele 1 –
+
allele 1allele 2
DNA
Example: test for Huntington’s disease
Uses: Forensics
• Comparing DNA sample from crime scene with suspects & victim
–
+
S1
DNA
S2 S3 V
suspects crime scene sample
DNA fingerprints
• Comparing blood samples on defendant’s clothing to determine if it belongs to victim– DNA fingerprinting
RFLP / electrophoresis use in forensics
• 1st case successfully using DNA evidence– 1987 rape case convicting Tommie Lee Andrews
“standard”
“standard”
“standard”
“standard”
semen sample from rapist
semen sample from rapist
blood sample from suspect
blood sample from suspect
How can you compare DNA from
blood & from semen?RBC?
Electrophoresis use in forensics
• Evidence from murder trial– Do you think suspect is guilty?
“standard”
blood sample 3 from crime scene
“standard”
blood sample 1 from crime scene
blood sample 2 from crime scene
blood sample from victim 2
blood sample from victim 1
blood sample from suspect OJ Simpson
N Brown
R Goldman
Uses: Paternity
• Who’s the father?
+
DNA
childMom F1 F2–
Homework
• Regents Review: Protein Synthesis
Biodiversity Lab
GENETIC ENGINEERINGLesson 6
Do Now
• T Chart
We have been manipulating DNA for generations!
• Artificial breeding– creating new breeds of animals & new crop
plants to improve our food
Animal breeding
Breeding food plants• “Descendants” of the wild mustard
– the “Cabbage family”
Breeding food plants
Evolution of modern corn (right) from ancestral teosinte (left).
TACGCACATTTACGTACGCGGATGCCGCGACTATGATCACATAGACATGCTGTCAGCTCTAGTAGACTAGCTGACTCGACTAGCATGATCGATCAGCTACATGCTAGCACACYCGTACATCGATCCTGACATCGACCTGCTCGTACATGCTACTAGCTACTGACTCATGATCCAGATCACTGAAACCCTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTGCTACTGATCTAGCTCAATCAAACTCTTTTTGCATCATGATACTAGACTAGCTGACTGATCATGACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACTGCTACTGATCTAGCTCAATCAAACTCTTTTTGCATCATGATACTAGACTAGCTGACTGATCATGACTCTGATCCCGTAGATCGGGTACCTATTACAGTACGATCATCCGATCAGATCATGCTAGTACATCGATCGATACT
human genome3.2 billion bases
Can we mix genes from one creature to another?
YES!
Mixing genes for medicine…
• Allowing organisms to produce new proteins– bacteria producing human insulin– bacteria producing human growth hormone
How do we do mix genes?
• Genetic engineering– find gene– cut DNA in both organisms– paste gene from one creature into other
creature’s DNA– insert new chromosome into organism– organism copies new gene as if it were its own– organism reads gene as if it were its own– organism produces NEW protein:
Remember: we all use the same genetic code!
Cutting DNA• DNA “scissors”
– enzymes that cut DNA
– restriction enzymes• used by bacteria to cut up DNA of
attacking viruses
• EcoRI, HindIII, BamHI
– cut DNA at specific sites• enzymes look for specific base sequences
GTAACGAATTCACGCTTCATTGCTTAAGTGCGAAGTAACG|AATTCACGCTTCATTGCTTAA|GTGCGAA
Restriction enzymes
• Cut DNA at specific sites
GTAACG AATTCACGCTTCATTGCTTAA GTGCGAA
GTAACGAATTCACGCTTCATTGCTTAAGTGCGAA
restriction enzyme cut site
restriction enzyme cut site
Uses of genetic engineering
• Genetically modified organisms (GMO)– enabling plants to produce new proteins
• Protect crops from insects: BT corn – corn produces a bacterial toxin that kills corn borer
(caterpillar pest of corn)
• Extend growing season: fishberries – strawberries with an anti-freezing gene from flounder
• Improve quality of food: golden rice – rice producing vitamin A
improves nutritional value
Bacteria
• Bacteria are great! – one-celled organisms– reproduce by mitosis
• easy to grow, fast to grow– generation every ~20 minutes
Bacterial DNA
• Single circular chromosome– only one copy = haploid– no nucleus
• Other DNA = plasmids!
bacteriachromosome
plasmids
There’s more…
• Plasmids– small extra circles of DNA– carry extra genes that bacteria can use– can be swapped between bacteria
• bacterial sex!!• rapid evolution = antibiotic resistance
– can be picked up from environment
How can plasmids help us?
• A way to get genes into bacteria easily– insert new gene into plasmid– insert plasmid into bacteria = vector– bacteria now expresses new gene
• bacteria make new protein
+
transformedbacteriagene from
other organism
plasmid
cut DNA
recombinantplasmid
vector
glue DNA
Grow bacteria…make more
growbacteria
harvest (purify)protein
transformedbacteria
plasmid
gene fromother organism
+
recombinantplasmid
vector
Applications of biotechnology
Homework
• Genetics Review