RNA’s structure and the Birth of the RNA triplets

RNA- Ribonucleic Acid

RNA’s Structure 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) 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) 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) 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 DNA must be copied to messenger RNA (mRNA) mRNA goes from nucleus to the ribosomes in cytoplasm mRNA complements known as codons One codon is 3 nitrogen bases long Remember RNA has uracil (U) instead of thymine (T)!

*DNA will serve as the template 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 The template strand is the DNA strand being copied The rRNA strand is the same as the DNA strand except Us have replaced Ts

STOP !!!!!

If you had the following DNA strand, what would be the complementary DNA strand ? A C G T A T C G C G T A G C T C A A G G T

If you had the following DNA strand, what would be the complementary mRNA strand? A C G T A T C G C G T A G C T C A A G G T

If you had the following mRNA strand, what would be the complementary tRNA? 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 A A U G U

tRNA structure 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 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! 20 amino acids 64 codon combinations

Translation- The Steps 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 everytime that happens tRNA will leave behind an amino acid.

Translation steps continued…….. 4. tRNA can’t start matching its anticodon and dropping off amino acids until it comes to the start codon (AUG). 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, ) 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 Where: Nucleus When: S phase of Interphase 2. Transcription- DNA produces the RNA triplets and gives the blueprint to make proteins to mRNA Where: Nucleus When: Right after DNA Replication 3. Translation – mRNA and tRNA work together with rRNA to combine amino acids to make proteins Where: Ribosome When: Right after Transcription