Transcript DNA to Protein - Seabreeze High School

DNA to Protein
Chapter 10
A Problem to Think About…
• DNA is in the nucleus
• The ribosome (protein factory) is
in the cytoplasm
• How do you get the DNA
information to the ribosome?
The Process
Figure 1 from textbook
Types of RNA involved
• mRNA- “messenger RNA”- takes message
of DNA out of nucleus to
ribosome
• rRNA- “ribosomal RNA”. This is what
ribosomes are made of
• tRNA- “transfer RNA”. Pairs with mRNA
and transfers the amino acids over
to build a protein
Transcription- DNA to mRNA
• A “scribe” writes down information for
someone else
• mRNA = “messenger” RNA
• The mRNA “writes down” the DNA
information and carries its “message” to
the ribosomes
• mRNA has Uracil instead of Thymine
Translation: mRNA to protein
• mRNA is “read” by the ribosomes in
codons (3 bases) at a time
• tRNA pairs with mRNA codons and amino
acid group is transferred and attached to
the one before it. This builds a protein.
• Use your codon chart to see what mRNA
codon “codes” for what amino acid.
• Protein chain continues to lengthen until a
“STOP” codon is reached.
Practice- #1
DNA (original):
mRNA:
UAGAUGUGACUC
tRNA:
AUCUACACUGAG
Amino Acids:
Pg. 211
ATCTACACTGAG
Isoleucine Tyrosine Threonine Glutamic
Practice- #2
DNA (original): G T A G C T G G A A G T
mRNA:
CAUCGACCUUCA
tRNA:
G UA G C U G GAA G U
Amino Acids:
Pg. 211
Histidine
Arginine
Proline
Serine
Practice- #3
DNA (original): A A G A C C A C G A C T
mRNA:
UUCUGGUGCUGA
tRNA:
AA G A C C A C G A C U
Amino Acids:
Pg. 211
Phenylalanine Tryptophan Cysteine
Stop
Things to think About & Discuss
1. What if a mutation occurs in the DNA?
Explain how could that affect the
organism’s protein?
2. What if a mutation occurs in 3rd base of
the codon? Will it always code for a
different amino acid? Explain.
Which is Worse?
1. Explain which is worse- a mutation in the
DNA or a mutation in the mRNA?
2. Explain which is worse- a point mutation
or a frameshift mutation- and why?