Protein Synthesis: Transcription and Translation

Proteins DNA codes for protein A segment of DNA that codes for a specific protein is called a gene When your body needs a protein, it follows the instructions in DNA on a specific gene to make one.

Protein synthesis problem! Where is DNA, the instructions for proteins located? In the nucleus

Protein synthesis problem! What inside of the cell makes proteins? Ribosomes Where are ribosomes located? Ribosomes in the cytosol

DNA to Protein Problem DNA cannot leave the nucleus Protein factories (ribosomes) are NOT in the nucleus and they cannot get into the nucleus

How does your body know how to make proteins? RNA to the rescue RNA carries DNA’s instructions The flow of genetic information: DNA to RNA to Protein

Protein Synthesis Two processes of protein synthesis Transcription Translation

Transcription Transcription rewrites DNA into RNA occurs in the nucleus makes mRNA start site nucleotides transcription complex

Transcription steps 1a. DNA separates 2b. Complementary RNA bases are correctly paired to one side of the DNA start site nucleotides transcription complex DNA

Transcription steps 3c. mRNA separates from DNA 4d. DNA reforms 5e. mRNA leaves the nucleus RNA

Transcription mRNA = messenger RNA mRNA carries the instructions for making a protein from the DNA to the protein factories (ribosomes) DNA

Practice Transcribe the left side of this strand of DNA A-T RNA base pairing rules C-G A - U C - G C-G T-A G-C

Practice DNA Left Side mRNA transcript A-T A C-G C T-A T G-C G

Practice DNA Left Side mRNA transcript A-T A U C-G C G T-A T G-C

Transcribe the left side of this DNA strand mRNA transcript T-A T A-T A G-C G

Transcribe the left side of this DNA strand mRNA transcript T-A T A A-T U G-C G C

Protein synthesis 1. Transcription 2. Translation

Transcribe this DNA strand T A C G A A T C G A C T

Transcribe this DNA strand T A C G A A T C G A C T A U G C U U A G C U G A

How to translate Divide your mRNA sequence into groups of three A U G C U U A G C U G A

How to translate Divide your mRNA sequence into groups of three A U G / C U U / A G C / U G A

How to translate 3 nitrogen bases = a codon (a word) 3 nitrogen bases = 1 amino acid Many amino acids = a protein Use the genetic code chart to translate into the correct amino acid sequence

Genetic code chart

How to translate A U G / C U U / A G C / U G A AUG = CUU = AGC = UGA =

How to translate A U G / C U U / A G C / U G A AUG = Met (Start translation) CUU = AGC = UGA =

How to translate A U G / C U U / A G C / U G A AUG = Met (Start translation) CUU = Leu AGC = UGA =

How to translate A U G / C U U / A G C / U G A AUG = Met (Start translation) CUU = Leu AGC = Ser UGA =

How to translate A U G / C U U / A G C / U G A AUG = Met (Start translation) CUU = Leu AGC = Ser UGA = Stop translation

How to translate A U G / C U U / A G C / U G A AUG = Met (Start translation) CUU = Leu AGC = Ser UGA = Stop translation Amino acid sequence = Met - Leu - Ser - Stop A bunch of amino acids = a protein