mRNA to ProteinThanks to Ms. Dozier and Ms. Kimball for many of these

slides!

3 Types of RNA•mRNA (messenger):

Brings info from DNA in

nucleus to ribosome in

cytoplasm

•tRNA (transfer):

associates three RNA

bases (codon) with

amino acid

•rRNA (ribosomal): part

of ribosomal machinery

Protein

•A protein is a polymer

•Monomers are called Amino Acids (AAs)

•AAs are held together by peptide bonds, so a protein is also called a polypeptide

•20 types of AAs

•Protein function is determined by the order and number of AAs

Amino

Acids•Each amino acid

has same

backbone

•Different “R”

groups

Protein Structure

•After the AAs are

strung together they

are folded into a 3-D

shape

•Must be folded to do

a job

•Unfolded proteins

called “denatured”

Protein Function

•Used for:

ocellular structure

omovement

odefense

otransport

ocommunication

•Enzymes are proteins that speed up chemical

reactions

How are proteins made?

•Now that we know a little more about

proteins and why they’re important, let’s

continue looking at how they are made!

•We’ve looked at the first part of protein

synthesis. What was it called?

2 Parts of Protein

Synthesis

1.Transcription

2.Translation

Translation (Part 2 of Protein Synthesis)•mRNA travels from nucleus to

cytoplasm and attaches to ribosome

•Ribosome "decodes" mRNA sequence

•Each 3 nucleotide mRNA section is a codon that codes for an amino acid (AA)

•Transfer RNAs (tRNAs) then transport the amino acids to polypeptide chain (each tRNA anticodon corresponds to an mRNA codon)

Codons•Series of 3 nucleotides

which codes for a specific amino acid.

•64 codons code for 20 amino acids.

o1 codon can code for ONE amino acid ONLY

oBut…

oSeveral codons can code for the same amino acid

Codons

•One start codon- AUG

oAlso codes for

Methionine (Met)

•3 stop codons

oUAA, UAG, UGA

Practice

•Use your Codon

Table and list the

amino acids in your

notes that each

codon codes for.

Amino Acid:

m

Protein Synthesis

•Translate this DNA sequence to mRNA,

tRNA, and then AAs in your notes:

•: TAC TGC ATA CTG GGC ATC

•: AUG ACG UAU GAC CCG UAG

•: UAC UGC AUA CUG GGC AUC

•:start Thr Tyr Asp Pro Stop

DNA

mRNA

AAs

tRNA

Use mRNA codon