The Central Dogma of DNA
• The process of making proteins in a cell!
DNADNA RNARNA ProteinProtein
Done in 2 steps: Transcription and Done in 2 steps: Transcription and TranslationTranslation
RNA
• Ribonucleic Acid• RNA is a molecule that helps synthesize
(make) proteins
• There are 3 kinds of RNA: mRNA, tRNA, rRNA• In RNA A pairs with U (there is no thymine)
DNA RNA
The sugar is Deoxyribose
The sugar is Ribose
Double stranded Single stranded
Bases = T, A, C, G
Bases = U, A, C, G
DNA never leaves the nucleus
RNA can leave the nucleus
The Central Dogma of DNAPart 1 - Transcription
So you’ve managed to sneak into the Cheeto’s factory and have found the safe where
they hide the secret recipe to make the “hotness” for the
Hot Cheetos
You only have 45 seconds before the alarm sounds and the security guards find you.
YOU NEED THIS RECIPE!
What are you going to do?
WRITE IT DOWN!So you write it down, but when you get So you write it down, but when you get
back home, you realize that the recipe is back home, you realize that the recipe is in Chinesein Chinese
What do you do?What do you do?
Have someone translate it into English!
- 3 Tomatoes - 3 Tomatoes - 4 Tbsp Pepper- 4 Tbsp Pepper- 5 cups of salt- 5 cups of salt
Now you can make any Now you can make any Cheeto HOT!Cheeto HOT!
What steps did we just do...
1. Write the recipe down1. Write the recipe down
2. Translate the recipe2. Translate the recipe
This is exactly what happens when DNA is used This is exactly what happens when DNA is used to make proteinsto make proteins
Review: What is a protein?• Made of amino acids:
• Polypeptide- Amino acids linked together- A protein
Labeling DNA Strands: 5’ vs 3’ DNA strands are labeled as
follows:Strand 1: 5’ ATCGTA 3’Strand 2: __ ______ __
The Central Dogma of DNA
• The process of making proteins in a cell!
DNADNA RNARNA ProteinProteinTranscriptiTranscripti
ononTranslationTranslation
2 Steps:
1. Transcription: Making a copy of the desired gene using mRNA
2. Translation: mRNA is used to make the protein with the help of ribosomes
Central Dogma Song
DNADNA RNARNAStep 1Step 1
TranscriptionTranscription
Transcription RNA reads and copies the DNA codeThis occurs in the NUCLEUSof the cellRules to write the mRNA
complimentary strand:Rule: A pairs with U “Aunt-Uncle”
C pairs with G “Chewing Gum”
• DNA: 5’ A T C G A T 3’• mRNA: 3’ _ _ _ _ _ _ 5’
Checking for Understanding Your turn…
1. DNA: GGATCCATGTTC mRNA:
2. DNA: TATGCGAAACAT mRNA:
Steps of Transcription:
1. DNA untwists and opens2. DNA is copied into mRNA with the help of
RNA Polymerase3. mRNA travels out of the nucleus to the
rough E.R.
What is mRNA?• mRNA = messenger RNA• The type of RNA that delivers the code
from the DNA to the ribosomes!
Exit Slip #1
The central dogma of DNA states that RNA is made from DNA. This process is called:
A translationB central dogmaC transcriptionD replication
Exit Slip #2
RNARNAProteiProtei
nn
Step 2Step 2
TranslationTranslationDNADNA
TranscriptionTranscription
Translation/CodonsTranslation: The process of converting RNA into PROTEINTHREE nucleotides (bases) on an mRNA sequence is called a codonOne codon codes for one amino acid– Ex: mRNA: AUG-CUU-CUC
3 codons 3 amino acids
AUCCUCCGCAUCCUCCGC
CODONCODON
CFU
1. How many bases, codons, and amino acids are in the following mRNA sequence?
AUG-AUG-AGG-CGG-CAA-UUU
bases:________ codons:_______ amino acids:________ 2. Which statement best explains how messenger RNA (mRNA)
provides a code for the formation of a protein?a. One base in the RNA codes for three amino acids in the
proteinb. Three bases in the RNA code for one amino acid in the
protein
Translation video
Translation Steps(RNA Protein)
mRNA travels out of the nucleus to Rough E.R./Ribosomes
ribosomes and tRNA link together amino acids to make a protein
Transfer RNA (tRNA)
tRNA is responsible for delivering the amino acids
tRNA has an anticodon • three bases on tRNA that match up to the
codon on the mRNA sequence
These are These are all amino all amino
acids!acids!
Find the amino acid sequence using the given DNA sequence and Codon Box that is provided
DNA: TAC-TTT-GTG-GTC-AAA-ATT
mRNA: AUG-AAA-CAC-CAG-UUU-UAA
Protein: Met-Lus-His-Gln-Phe-Stop
http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf
EXIT SLIP #1
1. What is the amino acid sequence for the DNA sequence :
ATGCCCGTTATC
A pro-leu-met-stopB tyr-gly-gln-stopC met-pro-tyr-glyD not enough information
Exit Slip #2
2. In the DNA sequence below, how many amino acids are coded for?
5’ ATGGGCTACGTTATA 3’
A 3B 2C 5D 0
WEDNESDAY: Textbook Questions Directions: Use Chapter 8.4 (pages 239-242) to
answer the following questions.
THURSDAY: Multiple-Choice QuestionsDirections: Write five multiple-choice questions that could be used on the quiz. Make them creative and challenging. Each question should have four choices (a-d).Question #1: ______________________________________________________________________ a) _______________________________________________________________
b) _______________________________________________________________c) _______________________________________________________________d) _______________________________________________________________
Central Dogma Race!
Complementary
mRNA Amino Acids (2)
AAA TTT ATG AAA UAC Lys-Tyr
GTT GCG CAA CGC GUU Arg-Val
ATC TAG GCG AUC CGC Lle-Arg
AGC CTT TCG GAA AGC CUU Ser-Leu
TAC ATG ATG TAC UAC AUG Tyr-Met
The Code
12.Each codon codes for a specific amino acid
– Ex) CUU = leucine
13.There are only 20 different amino acids used to make millions of different proteins
14. It’s all about the sequence (order) of amino acids!
CUUCUACGCCUUCUACGC
The Final Product: Protein19.Once all the amino acids are linked
together, a protein is formed20.Protein = many amino acids = polypeptide21.21.Why do we need proteins?Why do we need proteins?
A) Structure: Fingernails, Hair, CellsB) ENZYMES! - to speed up chemical reactions
Guided Practice
Step 1) Act as the enzyme _____ ____________ inside the nucleus and _____________ this DNA into mRNA:
3’ T A C T T T C A G G G T C A C A C T 5’ 5’ A T C A A A G T C C C A G T G T G A 3’mRNA _______________________________________5‘ A U G A A A G U C C C A G U G U G A 3’ 5‘ A U G A A A G U C C C A G U G U G A 3’
We are going to Transcribe and We are going to Transcribe and Translate DNA into mRNA into Amino Translate DNA into mRNA into Amino AcidsAcids
RNA PolymeraseRNA Polymerasetranscribetranscribe
Guided Practice ContinuedStep 2) Act as a ______________, the organelle that ________________ mRNA into amino acids in the __________________ of the cell.
5’ A U G A A A G U C C C A G U G U G A 3’ 5’ A U G A A A G U C C C A G U G U G A 3’ Break it down into Codons: Break it down into Codons: UAG, AAA, GUC, CCA, GUG, UAG, AAA, GUC, CCA, GUG, UGAUGA
Now use the Codon Table to translate the amino Now use the Codon Table to translate the amino acidsacids Your amino acids are:Your amino acids are:
____________ (____________ (always STARTalways START))____________ ____________ ____________________________________________________________________________________ (____________ (need an endneed an end))
ribosomeribosometranslatetranslatecytoplasmcytoplasm
MethionineMethionineLysineLysineValineValineProlineProlineValineValinestop codonstop codon