Download RNA & Protein Synthesis

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DNA & RNA

Long chain of
nucleotides
◦ 5-carbon sugar
◦ Phosphate group
◦ Nitrogen base

Nucleic acid
RNA Only




Ribonucleic acid
RNA sugar is
ribose
Single-stranded
Thymine replaced
with uracil
◦ Switch “T” for “U”
◦ (Think “GAUUACA”
instead of
“GATTACA”)
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

RNA is disposable copy of a DNA segment
Can copy one DNA sequence into many,
many, many copies of RNA
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
Three types of RNA
◦ Messenger RNA (mRNA)
◦ Ribosomal RNA (rRNA)
◦ Transfer RNA (tRNA)
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
RNA carries copies of genes – acts as
“messengers”
◦ Messenger RNA or mRNA
Must…get…
message…to…
ribosome!
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

Proteins are assembled on ribosomes
Ribosomes are made up of part protein, part
RNA
◦ Ribosomal RNA or rRNA

mRNA threads through the ribosome
ribosome
mRNA
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
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Found in cytoplasm
tRNA carries each amino acid to the
ribosome (where mRNA is waiting)
tRNA
A.A.
ribosome
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Replication
Transcription
Translation
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DNA

mRNA molecules are
made by copying part of
the DNA
◦ This process of
DNA  RNA is called
transcription

RNA is being formed
◦ Where normally would be
a T, now replace with U
mRNA
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
Normally:
◦
◦
◦
◦
◦
DNA : DNA
A : T
C : G
G : C
T : A

Transcription:
◦
◦
◦
◦
◦
DNA : RNA
A : U
C : G
G : C
T : A
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
What enzyme made
strands of DNA?
◦ DNA Polymerase

What enzyme would
make strands of RNA?
◦ RNA Polymerase
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
The RNA molecules might need some editing
before the final draft
◦ Introns are removed
 Think “intruder”
◦ Exons stay (they are “excellent”)
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A “word” of mRNA is called a “codon”
Each word is three letters long
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