13.2 Ribosomes and Protein Synthesis

The Genetic Code

Polypeptides are when amino acids join together to make long strands. 20 different amino acids are found in Polypeptides.

A,C,G, and U (adenine, cytosine, guanine, and uracil) the letters are called the genetic code. The genetic code is read three letters at a time, so that each "word" is three bases long and corresponds to a single amino acid. Each word is called a condon.

How to Read Codons

If you are trying to decode UGG

first go to the U the work your way to the next letter then after that the next letter.

If you match it up right you will get Tryptophan.

Start and Stop Codons

AUG (methionine) is a start codon which means that the strand starts there.

Then there is a stop codon which signals when the strand stops.

Translation

Once the polypeptide is complete it folds into its final shape.

The decoding of an mRNA message into a protein is called translation.

STEPS

1)mRNA attaches itself to a ribosome. tRNAs bring the right amino acids into the ribosomes. The ribosome then begins to attach the right amino acids onto the growing chain.

Each tRNA carries just one type of unpaired amino acid and it is called anticodon.

2)Form a peptide bond once the anticodon finds its match.

3)the polypeptide continues to grow until it reaches the stop codon.

Roles of tRNA and rRNA in Translation

tRNAs role is to decode mRNAs message so that the ribosome can find the right amino acid for the spot.

rRNAs role is to keep ribosomal proteins in place and to find the beginning of the mRNA message.

The Molecular Basis of Heredity

Basically that once polypeptide becomes a protein is when you start to get your skin color, pigment, hair color, eye color, and so on. Proteins are enzymes which produce a chemical reaction in which all of those happen.

Yes you may be thinking these notes are short, but thats because it was only about three pages.

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