DNA & Protein Synthesis • TEK 6C: I can explain

DNA & Protein Synthesis
• TEK 6C: I can explain
the purpose and
process of protein
synthesis
Transcription
DNA
Translation
mRNA
occurs in nucleus
Protein
occurs on ribosome
How is DNA and RNA similar? Different?
Description
DNA
Stands for…
Deoxyribonucleic acid
Number of
strands
Base Pair Rule Adenine = Thymine
Function
Where is it
found?
Types
Sketch Model
DNA
RNA
Thymine =
Adenine =
Cytosine =
DNA
RNA
What is Protein synthesis?
• Process where a gene of DNA is decoded
in order to make a protein.
– What’s a gene?
• Two parts to protein synthesis:
– Transcription
– Translation
• When does protein synthesis happen?
1st: DNA Transcription
• The word transcribe means “to copy”. During transcription, a gene
is transcribed into a mRNA strand.
• mRNA is known as “messenger” RNA because it carries the DNA
code or message out of the nucleus and into the cytoplasm.
• Where does transcription happen?:
• How does transcription happen?:
1.
2.
3.
Transcription Activity:
Transcribe the DNA strand on your handout into a strand of
mRNA.
REMEMBER: Uracil is in a RNA strand instead of
Thymine.
Example:
DNA: T-A-C—A-C-G—A-T-T
mRNA: A-U-G—U-G-C—U-A-A
2nd: Translation
• In translation, a ribosome reads the mRNA strand and
translates it into a polypeptide chain (protein).
• Where does translation happen?
• How does translation happen?
1.
2.
3.
4.
Codon Activity
• Organize your mRNA into three letter
blocks called codons.
• Example:
• mRNA: AUGUGCUAAG
•
AUG UGC UAC
Three letter blocks = codons
Codons
• Each codon codes for a
specific amino acid in the
protein chain.
• tRNA (transfer) matches
a particular codon to a
particular amino acid.
• Amino acids are joined
together in the correct
sequence to form a
polypeptide chain.
How do I read a Codon chart?
•
•
•
•
“First letter” represents the first
letter of a codon. Example: AUG
“Second letter” represents the
second letter of a codon.
Example: AUG
“Third letter” represents the third
letter of a codon. Example:
AUG
The amino acid coded for the
codon AUG is methionine.
It’s your turn to practice using the
codon chart! Identify the amino acids
represented by the codons on your
handout.
Tad..da..
Protein is
created!
Proteins fold
to activate
and function.
3-D Animation of Protein
Synthesis
• http://www.youtube.com/watch?v=nHM4U
UVHPQM