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RNA and PROTEIN SYNTHESIS
12-3
© Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved
RNA- the Other Nucleic Acid
NUCLEOTIDES
Also made of ___________
RIBOSE instead
Sugar is _______
of deoxyribose.
SINGLE stranded
RNA is _________
URACIL
Contains _________
instead
of thymine.
http://images2.clinicaltools.com/images/gene/dna_versus_rna_reversed.jpg
3 KINDS OF RNA HELP WITH INFO
TRANSFER FOR PROTEIN SYNTHESIS
RIBOSOMAL
_________________RNA
(rRNA)
Combines with proteins to form ribosomes
TRANSFER
_________________RNA
(tRNA)
Matches m-RNA codon to add correct
amino acids during protein synthesis
_________________RNA
(mRNA)
MESSENGER
carries code from DNA to ribosomes
rRNA and t-RNA images from © Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved
mRNA image from http://wps.prenhall.com/wps/media/tmp/labeling/1140654_dyn.gif
Figure 12–14 Transcription
Section 12-3
Adenine (DNA and RNA)
Cystosine (DNA and RNA)
Guanine(DNA and RNA)
Thymine (DNA only)
Uracil (RNA only)
RNA
polymerase
DNA
RNA
RNA POLYMERASE
Enzyme called _____________________
separates strands, then uses one strand
as a template to assemble an RNA copy.
How does RNA POLYMERASE know
where a gene starts and stops?
Enzyme binds to places with specific DNA
PROMOTERS
sequences called _______________.
RNA POLYMERASE
PROMOTERS tell _________________
where to start.
Signals at the end of the gene code cause
transcription to _____
stop .
http://images2.clinicaltools.com/images/gene/dna_versus_rna_reversed.jpg
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TRANSCRIPTION (12C)
ACTIVITY
• TRANSCRIPTION of DNA
NON CODING DNA
•
•
•
•
•
•
More than 90% of human DNA
“JUNK” DNA
Originally called ______________
REGULATION- Turn genes on/off
TELOMERES - protective ends
INTRONS
____________pieces edited out of message
PSEUDOGENES
- non functional genes due to mutations
• VIRAL ELEMENTS
- Leftovers from viral infections
TRANSPOSONS
• ________________
mRNA’s require EDITING before use
Image by Riedell
EX: antibody production
different
Immune system needs
to be able to make a
huge number of
different antibodies
to match new and
different invaders
http://www.sciencegeek.net/Biology/review/graphics/Unit8/Antibody.gif
http://1.bp.blogspot.com/_bjeC1CyB28w/TOijgcetVjI/AAAAAAAAAvo/0hPZmygfSZo/s1600/colourful_cartoon_germs_bumper_sticker-p128396365988627252trl0_400.jpg
•
•
•
•
•
•
TRANSPOSONS
“Jumping”
____________
genes
Can move from one place to another
1st described by Barbara McClintock in corn
Environmental stress increases jumping
Can move genes to new site
Increase mutation rate
http://www.nature.com/nature/journal/v443/n7111/images/443521a-i1.0.jpg
http://www.osti.gov/accomplishments/images/mcclintock_05.jpg
IT’S NOT “JUNK”!
• Allows same gene to be used in
different ways in different kinds of cells.
• Differences in organisms are more about
differences in regulation than in genes
themselves
• Role in evolution?
Small changes in genes can have a big effect
Mutations give natural selection new choices
MASTER PLAN
DNA stays safe in nucleus
© Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved
TRANSCRIPTION (DNA→ RNA)
& PROCESSING
takes place in nucleus
TRANSLATION (RNA→ proteins)
takes place on ribosomes
in cytoplasm
“Blueprints” of master plan
are carried to building site
http://www.home-improvement-resource.com/images/architect.jpg
HOW CAN JUST 4 BASES GIVE DIRECTIONS
TO MAKE 20 AMINO ACIDS?
Message is read in groups of 3 = _________
CODON
UCGCACGGU
UCG-CAC-GGU
Serine - Histidine - Glycine
Codons represent different amino acids
The m-RNA Code
Section 12-3
64 possible codons
Some amino acids
have more than one
codon.
AUG
START= _______
STOP
3 codons for _____
ANTICODON
___________
on tRNA
EACH tRNA
carries only
one kind of
amino acid
_____________
matches up with
CODON
________
on mRNA
Images modified from © Pearson Education Inc, publishing as Pearson Prentice Hall. All rights reserved
Figure 12–18 Translation
Section 12-3
Figure 12–18 Translation (continued)
Section 12-3
Video 4
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PROTEIN SYNTHESIS
(12D)
TRANSLATION VIDEO
(Choose Large video)
Mendel/flower images from: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookTOC.html
Blood cell by Riedell
GENES & PROTEINS
Proteins are the connection between
the gene code in the DNA and how that
gene is expressed.
A gene that codes for an enzyme (protein)
to make a pigment can control
the color of a flower.
A gene that codes for an enzyme (protein)
adds carbohydrates to glycoproteins to
produce your blood type.
Enzymes catalyze and regulate chemical reactions so
proteins build and operate all cell components.
REPLICATION
DNA → DNA ____________
TRANSCRIPTION
DNA → RNA ____________
RNA→ Protein TRANSLATION
___________
Concept Map
Section 12-3
can be
also called
which functions to
from
also called
to
which functions to
to make up
also called
which functions to
Concept Map
Section 12-3
RNA
can be
Messenger RNA
also called
Ribosomal RNA
which functions to
mRNA
Carry instructions
also called
which functions to
rRNA
Combine
with proteins
from
to
to make up
DNA
Ribosome
Ribosomes
Transfer RNA
also called
which functions to
tRNA
Bring
amino acids to
ribosome