Unit V: Molecular Genetics

Part IV: RNA & Protein

synthesis

Protein Synthesis

Intro•Your genetic code is made up of G, C, A, T, & U•Your genetic code tells your body what proteins to make•How do we make proteins from DNA?

Vocab•Ribosomes: Makes proteins•RNA: Ribonucleic acid•Proteins: macromolecule that is used for

structure & function •Amino Acids: building blocks of proteins (20

different AAs)•Codon: group of 3 nitrogenous bases that

code for a specific amino acid

Part 1: RNA

RNA•Long chain of nucleotides just like DNA

•What are nucleotides made up of?•___________________•___________________•___________________

Types of RNA•Messenger RNA (mRNA)•Ribosomal RNA (rRNA)•Transfer RNA (tRNA)

•Each type of RNA has its own specific job

mRNA•Carries instructions for assembling proteins from DNA to the ribosome •It’s the “messenger”

rRNA•Found on ribosomes•Remember: Ribosomes make proteins J

tRNA•Transfers amino acids to the ribosome to construct proteins

How do we turn DNA into

proteins?

Part 2: Transcription

DNA → RNA → Protein

Transcription•A process of copying part of DNA into mRNA•Takes place within the nucleus•What does DNA polymerase do?

Transcription•RNA polymerase works in the same way!•mRNA is formed when RNA polymerase uses one strand of DNA as a template to form a strand of RNA

Transcription

Codons•Codons are groups of 3 nitrogenous bases that code for a specific amino acid

Steps of Transcription

How do we turn RNA into

proteins?

Part 3: Translation

DNA → RNA → Protein

Translation•Decoding (or translating) a mRNA message into a protein

Translation Steps1. mRNA is transcribed from DNA & leaves the nucleus

(transcription)2. mRNA attaches to a ribosome•Which type of RNA is found on the ribosome?

3. Each mRNA codon moves through the ribosome

Translation Steps4. tRNA brings the proper amino

acid into the ribosome5. Each tRNA has 3 nitrogenous

bases that are complementary to one mRNA codon (anticodon)

Translation Steps6. The amino acids bond together forming a protein7. Proteins continue to grow until the ribosome

reaches a stop codon8. Translation is complete & a protein is formed

Next…•Learn how to read the

genetic code •Which codons match

with which amino acids?