Download RNA nucleotides

RNA’s structure and the Birth of the
RNA triplets
Mrs. New-New
RNA- Ribonucleic Acid
RNA’s Structure
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1.
2.
3.
Has a single strand made up of many
nucleotides
There are 3 types
mRNA
tRNA
rRNA
RNA Nucleotide
RNA has four nitrogen bases
Purines- 2 rings
 Adenine
 Guanine
Pyrimidines- 1 ring
 Cytosine
 Uracil (replace Thymine)
THE RNA TRIPLETS
mRNA- Messenger RNA (Lil Momma)
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Born during transcription in the nucleus
Her father is DNA (Big Daddy)
She is the most important of the RNA triplet
DNA gave her the blueprint needed to make
proteins
Once she has the blueprint needed to make
proteins she is going to leave DNA in the
nucleus and travel to a ribosome
3 nitrogen bases on her = 1 codon
tRNA- Transfer RNA (Tyrone)
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Born during transcription in the nucleus
His father is DNA (Big Daddy)
He is going to help mRNA (Lil Momma) in her
mission to make proteins by dropping off amino
acids
He is also going to leave the nucleus and travel
to a ribosome.
3 nitrogen bases on him= 1 anticodon
rRNA- Ribosomal RNA (Ramada Inn)
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Born during transcription in the nucleus
Its father is DNA (Big Daddy)
It will also leave the nucleus and combine with
a ribosome
This is the place where mRNA and tRNA will
meet to “translate” and make proteins
Transcription
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DNA must be copied to messenger RNA
(mRNA)
mRNA goes from nucleus to the ribosomes in
cytoplasm
mRNA complements known as codons
–
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One codon is 3 nitrogen bases long
Remember RNA has uracil (U) instead of
thymine (T)!
Transcription
1.
2.
3.
DNA is unzipped by the enzyme RNA
Polymerase at the promoter region.
RNA Polymerase will then drop off
complementary RNA nucleotides to Big
Daddy’s exposed bases on one side. (She is
making mRNA=Lil’ Momma, however all
three triplets are being made.
She will stop dropping off nucleotides when
she comes to the termination signal.
Transcription continued………
4. Lil” Momma now has the blueprint to make
proteins and is ready to leave the nucleus; but
before she can leave, she has to be edited.
(Introns are taken out and Exons are put back
together)
5. mRNA, tRNA, and rRNA will now leave the
nucleus and travel to a ribosome.
6. DNA zips back up.
- This happens in the nucleus, right after DNA
replication
Transcription – Step I
A C G T A T C G C G T A
T G C A T A G C G C A T
DNA unzips
*DNA will serve as the
template
Transcription – Step II
A C G T A T C G C G T A
U G C A U A G C G C A U
Template DNA is Matched Up with
Complementary RNA Nucleotides
Transcription – Step III
A C G U A U C G C G U A
U G C A U A G C G C A U
mRNA leaves nucleus
and goes to ribosomes
A new complementary RNA strand is
made (rRNA)
Transcription – Step IV
A C G T A T C G C G T A
T G C A T A G C G C A T
DNA zips back up
Transcription Reminders
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The template strand is the DNA strand being
copied
The rRNA strand is the same as the DNA
strand except Us have replaced Ts
Translation Notes
It’s Newson baby!!
If you had the following DNA strand,
what would be the complementary DNA
strand ?
A C G TAT C G C G TA G C T C AA G G T
If you had the following DNA strand,
what would be the complementary
mRNA strand?
A C G TAT C G C G TA G C T C AA G G T
If you had the following mRNA strand,
what would be the complementary
tRNA?
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How many codons are on this strand of
mRNA?
7
C G A U A U C G A G U A U C U C AA U G U
tRNA structure
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3-nitrogen base code is called an “anticodon”
tRNA has an anticodon attached to one end
and an amino acid attached to the other
Translation
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The genetic code found mRNA is “translated”
into proteins
The codons on mRNA are what’s important.
They specify or code for specific amino acids.
Codon code is specific!
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20 amino acids
64 codon combinations
Translation- The Steps
1.
2.
3.
rRNA (Ramada Inn) combines with protein to
become apart of the ribosome. mRNA and
tRNA will arrive at this ribosome.
mRNA (Lil Momma) contains codons (eggs)
that are complementary to tRNA’s (Tyrone)
anticodons (sperm).
tRNA will match it’s anticodon to mRNA’s
codon and every time that happens tRNA will
leave behind an amino acid.
Translation steps continued……..
4. However, tRNA can’t start matching its anticodon and
dropping off amino acids until it comes to the start
codon (AUG). Now once it sees the start codon, it’s
on!!!!
5. tRNA will keep matching it’s anticodon with mRNA’s
codon and leaving behind amino acids until it comes to
one of the stop codons. (UAG, UGA, UAA)
6. Once tRNA comes to a stop codon, it will stop
translating mRNA and the long chain of amino acids
will break off and become a protein (polypeptide).
Remember proteins are made by three
processes that happen in order.
1. DNA replication – DNA makes a copy of itself
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Where: Nucleus When: S phase of Interphase
2. Transcription- DNA produces the RNA triplets and
gives the blueprint to make proteins to mRNA
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Where: Nucleus
When: Right after DNA Replication
3. Translation – mRNA and tRNA work together with
rRNA to combine amino acids to make proteins
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Where: Ribosome When: Right after Transcription