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Protein synthesis. Major players in protein synthesis : mRNA, tRNA and the ribosome. RNA vs DNA. RNA’s are nucleotides like DNA however there are some differences. Who knows some differences between the two?. Step 1. DNA splits into two strands using enzyme helicase. Transcription.
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Protein synthesis Major players in protein synthesis: mRNA, tRNA and the ribosome
RNA vs DNA • RNA’s are nucleotides like DNA however there are some differences. • Who knows some differences between the two?
Step 1 • DNA splits into two strands using enzyme helicase.
Transcription • Step 2: One strand of DNA is copied into mRNA. • Step 3: The message from the DNA is delivered to the ribosomes in the cytoplasm.
mRNA • Messenger RNA, a copy of DNA blueprint of the gene to be expressed. • Information
How does the RNA attach? • RNA polymerase is an enzyme that attaches the RNA to one strand of DNA
Translation • Step 4: nucleotides in mRNA determines the sequence of amino acids in a protein.
3 nucleotides in an mRNA molecule codes for one amino acid in a protein. • Each set of 3 nucleotides is called a codon • Each codon specifies a particular amino acid.
tRNA • transfer RNA, also called anticodon molecule. tRNAs bring each amino acid. • Supply
Ribosome • A very large complex of several rRNAs(ribosomal RNA) and many protein molecules. • Factory
Protein • Polypeptide chain with sequence dictated by the mRNA sequence. Also called the gene product. • Product
Mutation • Copying error when DNA replicates itself • The older we get, the more mistakes our cells make. • Outside factors can also cause mutations • Sunlight • Cigarette smoke • Radiation
Point Mutation A point mutation is a change in one base of the gene sequence. This is equivalent to changing one letter in a sentence, such as this example, where we change the 'c' in cat to an 'h': Original • The fat cat ate the wee rat. • Point Mutation The fat hat ate the wee rat.
Deletion • Mutations that result in missing DNA are called deletions. These can be small, such as the removal of just one "word," or longer deletions that affect a large number of genes on the chromosome. In this example, the deletion eliminated the word cat. • Original: • The fat cat ate the wee rat. • Deletion: The fat ate the wee rat.
Insertion • Mutations that result in the addition of extra DNA are called insertions. Insertions can result in a nonfunctional protein. • Original • The fat cat ate the wee rat. • Insertion The fat cat xlw ate the wee rat.
