1. Protein Synthesis
RNA

2. RNA : Single stranded nucleic acid that makes proteins
Recall: Genes are coded DNA instructions that control protein production.
DNA must be copied to RNA (mRNA)
RNA structure: identical to DNA except:
Sugar = Ribose
Single Stranded
Nitrogen base pairs = C, G, A, and Uracil (U) (replaces thymine)

3. 3 Types of RNA
Messenger RNA (mRNA): Carries a copy of instructions to make proteins from DNA in nucleus → cytoplasm (ribosomes).
Transfer RNA (tRNA): Transfers amino acids to the ribosomes for protein assembly.
Ribosomal RNA (rRNA): Makes up the ribosomes.
(Amoeba Sisters RNA Recap)

4. Transcription
Transcription: Process by which a portion of DNA is copied to a complementary RNA sequence inside the nucleus.
Requires RNA polymerase (an enzyme)
Binds to DNA and separates strands
Uses DNA strand as template to make RNA complement

5. The Genetic Code “Language” of mRNA instructions.
Read 3 letters at a time, called a codon, that specify a single amino acid (monomer of a protein).
64 total possible codons =
20 amino acids
Example:
AUG/UGG/CUU/GCA/UGA
Start codon
Methionine / Tryptophan / Leucine/ Alanine / Stop codon

6. Translation
Translation: the decoding of an mRNA sequence into amino acids on ribosomes
Begins at AUG (“start” codon) Universal start codon= Methionine
Codons of mRNA match up with Anticodons of complementary tRNA
Translation continues until a “stop” codon is read (UAA, UAG, UGA)
Result is chain of new proteins!!

7. Protein Assembly
Amino acids connect with peptide bonds to form proteins (“polypeptides”)
Proper synthesis of proteins is essential to organism survival
Proteins are enzymes – catalysts that increase rate of reactions
“By coding for proteins, DNA holds the key to life”
(Amoeba Sisters Recap Protein Synthesis)