“central dogma” · ap biology “central dogma” replication dna rna protein trait
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AP Biology
“Central Dogma”
replication
protein RNA DNA trait
http://www.youtube.com/watch?v=_Q2Ba2cFAew
AP Biology
DNA Replication
DNA replication animation with description:
http://www.youtube.com/watch?v=teV62zrm2P0
http://www.youtube.com/watch?v=zdDkiRw1PdU&feature=related
DNA replication
http://glencoe.mcgraw-
hill.com/sites/9834092339/student_view0/chapter14/dna_replication.html
AP Biology 2013-2014
From Gene to Protein
How Genes Work
http://www.youtube.com/watch?v=_Q2Ba2cFAew
AP Biology
What do genes code for?
proteins cells bodies
How does DNA code for cells & bodies?
how are cells and bodies made from the
instructions in DNA
DNA
AP Biology
DNA
RNA
ribosomes
endoplasmic
reticulum
vesicle
Golgi
apparatus
vesicle
protein on its way!
protein finished protein
Making Proteins
TO:
TO:
TO:
TO:
nucleus
AP Biology
The “Central Dogma” Flow of genetic information in a cell
How do we move information from DNA to proteins?
replication
protein RNA DNA trait
DNA gets all the glory,
but proteins do all the work!
http://www.nobelprize.org/educational/medicine/
dna/a/transcription/index.html
AP Biology
Inheritance of metabolic diseases
suggested that genes coded for enzymes
each disease (phenotype) is caused by
non-functional gene product
lack of an enzyme
Tay sachs
PKU (phenylketonuria)
albinism
Am I just the sum of my proteins?
Metabolism taught us about genes
A B C D E
disease disease disease disease
enzyme 1 enzyme 2 enzyme 3 enzyme 4
metabolic pathway
AP Biology
Beadle & Tatum 1941 | 1958
George Beadle
Edward Tatum
"for their discovery that genes act by
regulating definite chemical events"
one gene : one enzyme hypothesis
http://jackbagwell.com/Micro/SWFs/13_3_1a.html
AP Biology
Wild-type Neurospora
Minimal medium
Select one of the spores
Grow on complete medium
Minimal control
Nucleic acid
Choline Pyridoxine Riboflavin Arginine
Minimal media supplemented only with…
Thiamine Folic acid
Niacin Inositol p-Amino benzoic acid
Test on minimal medium to confirm presence of mutation
Growth on complete medium
X rays or ultraviolet light
asexual spores
spores
Beadle & Tatum create mutations
positive control
negative control
experimentals
amino acid supplements
Where is the growth!
How would you interpret
this?
AP Biology
mRNA
From gene to protein
DNA transcription
nucleus cytoplasm
a
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protein translation
ribosome
trait
Central dogma song
http://www.youtube.com/watch?v=_Q2Ba2cFAew
AP Biology 2013-2014
Transcription
from
DNA (nucleic acid) language
to
RNA (nucleic acid) language
http://www.youtube.com/watch?v=WgvnFYyJGZQ&feature=mfu_in_
order&list=UL
http://www.nobelprize.org/educational/medicine/dna/a/transcri
ption/index.html
http://www.youtube.com/watch?v=5MfSYnItYvg&feature=related
AP Biology
RNA ribose sugar
N-bases
uracil instead of thymine
U : A
C : G
single stranded
lots of RNAs
mRNA, tRNA, rRNA, siRNA…
RNA DNA transcription
How do RNA and DNA differ?
AP Biology
Transcription Making mRNA
transcribed DNA strand = template strand
untranscribed DNA strand = coding strand same sequence as RNA
synthesis of complementary RNA strand transcription bubble
enzyme RNA polymerase
template strand
rewinding
mRNA RNA polymerase
unwinding
coding strand
DNA C C
C
C
C
C
C
C
C C C
G
G G
G
G G
G G
G
G
G A
A
A A A
A
A
A
A
A A
A
A T
T T
T
T
T
T
T
T T
T
T
U U
5
3
5
3
3
5 build RNA 53
http://www.youtube.com/watch?v=WgvnFYyJGZQ&feature=mfu_in_order&list=UL
http://www.youtube.com/watch?v=4X8eK15R8yY&feature=related
AP Biology
Matching bases of DNA & RNA Match RNA bases to DNA
bases on one of the DNA
strands
U
A G G G G G G T T A C A C T T T T T C C C C A A
U
U U
U
U
G
G
A
A
A C C RNA
polymerase
C
C
C
C
C
G
G
G
G
A
A
A
A
A
5' 3'
AP Biology
mRNA
From gene to protein
DNA transcription
nucleus cytoplasm
a
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a
ribosome
trait
protein translation
AP Biology 2013-2014
Translation
from
nucleic acid language
to
amino acid language
http://www.youtube.com/watch?v=5bLEDd-PSTQ
http://www.youtube.com/watch?v=5bLEDd-PSTQ&feature=related
http://www.youtube.com/watch?v=TfYf_rPWUdY&feature=related
http://www.youtube.com/watch?v=TfYf_rPWUdY
&feature=player_detailpage
AP Biology
How does mRNA code for proteins?
TACGCACATTTACGTACGCGG DNA
AUGCGUGUAAAUGCAUGCGCC mRNA
Met Arg Val Asn Ala Cys Ala protein
?
How can you code for 20 amino acids
with only 4 nucleotide bases (A,U,G,C)?
4
4
20
ATCG
AUCG
AP Biology
Cracking the code 1960 | 1968
Crick
determined 3-letter (triplet) codon system
Nirenberg & Khorana
WHYDIDTHEREDBATEATTHEFATRAT WHYDIDTHEREDBATEATTHEFATRAT Nirenberg (47 of possible combinations) &
Khorana (17 combinations gave ambiguous
results)
determined mRNA–amino acid match
added fabricated mRNA to test tube of
ribosomes, tRNA & amino acids
created artificial UUUUU… mRNA
found that UUU coded for phenylalanine
AP Biology
AUGCGUGUAAAUGCAUGCGCC
mRNA codes for proteins in triplets
TACGCACATTTACGTACGCGG DNA
AUGCGUGUAAAUGCAUGCGCC mRNA
Met Arg Val Asn Ala Cys Ala protein
?
codon
“codons”
AP Biology
The code Code for ALL life!
strongest support for
a common origin for
all life
Code is redundant
several codons for
each amino acid
3rd base “wobble”
Start codon
AUG
methionine
Stop codons
UGA, UAA, UAG
Why is the wobble good?
AP Biology
How are the codons matched to amino acids?
TACGCACATTTACGTACGCGG DNA
AUGCGUGUAAAUGCAUGCGCC mRNA
amino acid
tRNA anti-codon
codon
5 3
3 5
3 5
UAC
Met
GCA
Arg
CAU
Val
AP Biology
mRNA
From gene to protein
DNA transcription
nucleus cytoplasm
a
a
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a
a
ribosome
trait aa
protein translation
http://www.dnalc.org/view/15481-Translation-
RNA-to-protein-3D-animation-with-no-audio.html
AP Biology
Transfer RNA structure “Clover leaf” structure
anticodon on “clover leaf” end
amino acid attached on 3 end
AP Biology
Loading tRNA Aminoacyl tRNA synthetase
enzyme which bonds amino acid to tRNA
bond requires energy
ATP AMP
bond is unstable
so it can release amino acid at ribosome easily
activating enzyme
anticodon
tRNATrp binds to UGG condon of mRNA
Trp Trp Trp
mRNA A C C U G G
C=O
OH OH
H2O O
tRNATrp
tryptophan attached to tRNATrp
C=O
O
AP Biology
Ribosomes Facilitate coupling of
tRNA anticodon to
mRNA codon
organelle or enzyme?
Structure
ribosomal RNA (rRNA) & proteins
2 subunits
large
small E P A
AP Biology
Ribosomes
Met
5'
3'
U U A C
A G
A P E
A site (aminoacyl-tRNA site)
holds tRNA carrying next amino acid to
be added to chain
P site (peptidyl-tRNA site)
holds tRNA carrying growing
polypeptide chain
E site (exit site)
empty tRNA
leaves ribosome
from exit site
http://www.youtube.com/watch?v=5bLEDd-PSTQ
http://www.youtube.com/watch?v=1PSwhTGFM
xs&feature=related
AP Biology
Initiation brings together mRNA, ribosome
subunits, initiator tRNA
Elongation adding amino acids based on
codon sequence
Termination end codon 1 2 3
Leu
Leu Leu Leu
tRNA
Met Met Met Met
P E A
mRNA 5' 5' 5' 5'
3' 3' 3' 3'
U U A A A A C
C C
A U U G G G U
U A
A A A C
C C
A U U G G G U
U A
A A A C
C C
A U U G G G U U
A A A C
C A U U G G
Val Ser
Ala Trp
release factor
A A A
C C U U G G 3'
http://www.nobelprize.org/educational/medicine/dna/a/trans
lation/index.html
http://www.youtube.com/watch?v=XRIQqQ1cMTY
http://www.youtube.com/watch?v=q_n0Ij3K_Ho
Building a polypeptide
AP Biology
Can you tell
the story?
AP Biology
Can you tell the story?
DNA
pre-mRNA
ribosome
tRNA
amino acids
polypeptide
mature mRNA
5' GTP cap
poly-A tail
large ribosomal subunit
small ribosomal subunit
aminoacyl tRNA
synthetase
E P A
5'
3'
RNA polymerase
exon intron
tRNA
AP Biology
Transcription and Translation
http://juang.bst.ntu.edu.tw/BCbasics/images/PC
R.gif
AP Biology
Transcribe & translate a gene
http://learn.genetics.utah.edu/content/begin/dna/transcribe/
AP Biology AAAAAAAA GTP
20-30b
3'
promoter transcription
stop
transcription
start
introns
The Transcriptional unit (gene?)
transcriptional unit (gene) TAC ACT
DNA
DNA TATA 5' RNA
polymerase
pre-mRNA
5' 3'
translation
start
translation
stop
mature mRNA
5' 3'
UTR UTR
exons enhancer
1000+b
AP Biology 2013-2014
Any Questions??
What color would a smurf turn if he held his breath?
AP Biology
Tutorials Transcription Tutorials:
http://www-
class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a2.html
http://www-
class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html Translation Tutorials:
http://highered.mcgraw-
hill.com/sites/0072556781/student_view0/chapter12/animation_quiz_
1.html
http://highered.mcgraw-
hill.com/sites/0072556781/student_view0/chapter12/animation_quiz
_2.html
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