Transcription and Translation
What you will learn today
In Transcription, DNA is copied to make a strand of
RNA.
Transcription occurs in the nucleus.
In Translation, proteins are made from RNA.
Translation occurs in the ribosome.
Codons are 3 nucleotides that code for an
amino acid, which then make proteins.
The Gene Scene:
http://www.youtube.com/watch?v=xc2wbIDfO7E
DNA Structure video:
http://www.youtube.com/watch?v=qy8dk5iS1f0&feature=player_embedded
Deoxyribonucleic Acid
Deoxyribose
Double Stranded
A, T, C, G
Full Name
Sugar
Structure
Nitrogen Bases
Ribonucleic Acid
Ribose
Single Stranded
A, U (Uracil), C, G
Nucleus
Location
Picture
Outside of the nucleus
(ribosome)
DNARNAProtein
•
DNA has the instructions for the order of amino
acids which determines the proteins that make up
the traits (including physical characteristics such as
height, eye color, hair color, etc.) of any organism.
Function: A single strand of
RNA is made from DNA.
DNA RNA
Location: Nucleus
The DNA is kept safe in the
nucleus while the RNA is sent
out into the cell to direct the
building of proteins
http://www.concord.org/~btinker/workbench_web/models/euk
Transcription.swf
1. RNA polymerase (an enzyme)
attaches to DNA at a special
sequence that serves as a “start
signal”.
2. The DNA strands are separated
and one strand serves as a
template.
3. The RNA bases attach to the
complementary DNA template,
and mRNA is made!
4. The RNA polymerase recognizes
a ‘stop’ part on the DNA
molecule and releases the new
mRNA molecule.
• (mRNA leaves the nucleus and
travels to the ribosome in the
cytoplasm.)
http://www.stolaf.edu/people/giannini/fla
shanimat/molgenetics/transcription.swf
Transcribe this strand of DNA into
RNA (Transcription!):
DNA: AATCTAGATCATTA
RNA:________________
*Remember: There are
no ‘T’s in RNA!
Function: Pieces of RNA
make amino acids, which
then make proteins.
RNA Proteins
Location: Ribosome
http://www.concord.org/~btinker/workb
ench_web/models/eukTranscription.swf
There are different types of RNA:
mRNA: messenger RNA
Carries a message (genetic
code) from the nucleus to the
ribosome (how to make
proteins)
tRNA: transfer RNA
Transports amino acids to the
ribosome
1.
mRNA leaves the nucleus and
binds to a ribosome.
2.
The ribosome looks for
codons.
Codon: group of 3 nucleotides on
the messenger RNA that
specifies one amino acid.
3.
4.
tRNA (transfer RNA) carries Amino
Acids to the mRNA.
This tRNA has an anticodon that
matches the codon on the mRNA
strand.
Anticodon: group of 3 unpaired nucleotides
on a tRNA strand.
5.
Each amino acid is dropped off and a
chain forms. When the chain is
completed, it disconnects and makes
a protein!
Interactive animations :
•http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html
•http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf
The mRNA sequence reads the
following codons. What amino acids
do they stand for?
AUG
GGA
GAG
CAA
What amino acid does the
anticodon CGU stand for?
Find the amino acid sequence for the
following mRNA sequence
(translation):
AUGCGACGAAUUUAA
First-- Transcribe this strand of DNA
into mRNA:
DNA: AATCTAGATCATTAC
RNA:________________
*Remember: There are no ‘T’s in RNA!
Second—Translate that strand of mRNA
into amino acids.
DNA: AATCTAGATCATTAC
RNA: UUAGAUCUAGUAAUG
AA: ___ ___ ___ ___ ___
Second—Translate that strand of mRNA
into amino acids.
DNA: AATCTAGATCATTAC
RNA: UUAGAUCUAGUAAUG
AA: Leu Asp Leu Val Met
Transcription
Translation
Proteins
mRNA
Ribosome
Nucleus
Ribosome
Amino Acids