Goal 3.01b: Protein Synthesis and Gene Regulation

Goal 3.01b: Protein Synthesis and Gene Regulation

From Gene to Protein

Central Dogma

Bodies are made up of cells All cells run on a set of instructions

spelled out in DNA

Bodies Cells DNA

What makes it possible for different people…What makes it possible for different people…

… to have different faces?

i.ivillage.com www.learnwell.org

symonsez.files.wordpress.com

…to

be

diff

eren

t he

ight

s?

neveryetmelted.com

www.saidaonline.com

…to have different colored eyes?

Makes this protein…Makes this protein…

or this protein…or this protein…

or this protein!or this protein!

Each DNA makes a specific protein.

Those proteins

give us our looks.

cr4.globalspec.com

gamespot.com

Remember… Bases match together

A pairs with T A : T

C pairs with GC : G

weak bonds between bases join 2 strands can separate easily

Now it is time to find out how DNA manages to create so many different

kinds of organisms using only FIVE pieces of information!

What do we know? DNA

DNA is the genetic information

Proteins proteins run living organisms enzymes

all chemical reactions in living organisms are controlled by enzymes (proteins)

structure all living organisms are built out of proteins

DNA is the instructions for making proteins

What else do we know? DNA

DNA is in the nucleus want to keep it there =

protected

Proteins made by a “protein

factory” in cytoplasm ribosomes

Need to get gene (DNA) information from nucleus to cytoplasm need a messenger! need a copy of DNA mRNA

• deoxyribose sugar • nitrogen bases

– G, C, A, T• T = thymine

– T : A– C : G

• double stranded

• ribose sugar • nitrogen bases

– G, C, A, U• U = uracil

– U : A– C : G

• single stranded

DNA RNA

mRNADNA

transcription

nucleus cytoplasm

proteintranslation

trait

A brief overview of what happens…

DNA (double helix) is too big to go through the pores in the nuclear envelope.

The problem with DNA…

RNA (single helix) is small.

DNA gives its information to mRNA (messenger RNA) to carry out of the nucleus.

TOO BIG!

Just right.

• Making mRNA from DNA• DNA strand is the

template (pattern)– match bases

• U : A• G : C

• Enzyme– RNA polymerase

mRNA

TRANSCRIPTION

Making mRNA from DNA

A G GGGGGT T A C A C T T T T TC C C CA A

TRANSCRIPTION

A G GGGGGT T A C A C T T T T TC C C CA A

U U U U U

• Double stranded DNA unzips

A G GGGGGT T A C A C T T T T TC C C CA A

TRANSCRIPTION

• Use RNA polymerase• Match free floating RNA

bases to DNA bases on one of the DNA strands

U

A G GGGGGT T A C A C T T T T TC C C CA A

U

UU

U

U

G

G

A

A

A C CRNA

polymerase

C

C

C

C

C

G

G

G

G

A

A

A

AA

TRANSCRIPTION

Free-floating nucleotides

DNA

mRNA

TRANSCRIPTION

T A C G C A T T T A C G T A G C G G

l I I I I I I I I I I I I I I I I I

A U G C G U A A A U G C A U C G C C

Transcription Animationhttp://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf

U instead of T is matched to AU instead of T is matched to A

We are transcribing DNA into RNA.We are transcribing DNA into RNA.

What do we know NOW? DNA

instructions remain in nucleus

mRNA has the instructions for building

proteins from DNA

Proteins built as chains of amino acids

What reads RNA? need a mRNA reader! rRNA in ribosomes

aa

aa

aa

aa

aa

aa

aa

U C CCCCCA A U G U G A A A A AG G G GU U

aa

mRNAmRNA

From gene to protein

DNADNA

nucleus

ProteinProtein

TraitTrait

U C CCCCCA A U G U G A A A A AG G G GU UrRNA

ribosome

mRNA leaves nucleus through

nuclear poresrRNA inside the ribosomes synthesize amino acids to

make a protein using instructions on mRNA

Transcription

CELL

aa

aa aa

aa

aa

aa

Translation

mRNA has the instructions for building proteins

from DNA

Proteins built as chains of amino acids linked by

peptide bonds

What reads mRNA? ribosome

What brings the right amino acid to attach to the protein chain? need an amino acid transporter!

tRNA

aa

a

aaa

aa

aa

aa

What do we ALSO know now?U C CCCCCA A U G U G A A A A AG G G GU U

ribosome

Peptide bonds

mRNAmRNA

From gene to protein

DNADNA

nucleus

ProteinProtein

TraitTrait

U C CCCCCA A U G U G A A A A AG G G GU Uribosome

Transcription

cytoplasm

CELL

aa

aa aa

aa

aa

aa

Translation

aa

tRNA carries the correct amino acid (based on the

mRNAcode) to the ribosome.

Protein SynthesisProtein SynthesisLet’s build a flow chart!

TRANSCRIPTIONDNA gives mRNA blueprints for making a specific protein.

mRNA carries the blueprints out of the nucleus to the cytoplasm and finds a ribosome.

TRANSLATIONrRNA reads the mRNA inside the ribosome.

tRNA brings the correct amino acid to the mRNA.

An amino acid chain is built: PROTEIN.

Protein give us our traits.

BUILD DNA AND DISCOVER GENES!http://learn.genetics.utah.edu/content/begin/dna/

1. What is DNA?2. What is a Gene?3. Build a DNA Molecule.

How does tRNA know which amino acid to bring?

• When mRNA leaves nucleus it has a blueprint of DNA’s instructions.

• mRNA goes to ribosomes in cytoplasm• Ribosomes read the blueprint on mRNA.

aa aa aa aa aa aa aa aa

mRNA

U C CCCCCA A U G U G A A A A AG G G GU Uribosome

Using the template…

TACGCACATTTACGTACGCGGDNA

AUGCGUGUAAAUGCAUGCGCCmRNA

Met Arg Val Asn Ala Cys Alaprotein

?

How can you code for 20 amino acids with only 4 nucleotide bases (A,U,G,C)?

AUGCGUGUAAAUGCAUGCGCC

mRNA codes for proteins in triplets

TACGCACATTTACGTACGCGGDNA

AUGCGUGUAAAUGCAUGCGCCmRNA

Met Arg Val Asn Ala Cys Ala

Aminoacid

?

ribosome

Codon = set of 3 bases

Anticodon = set of 3 basesUAC

The code is UNIVERSAL!

• Since all living organisms… – use the same DNA– use the same code

book– read their genes the

same way

AUG

What amino acids are

coded for by these

codons?

UGAACUAACGAG

• For ALL life!– Uses only 4 bases for

ALL life. (strongest support for a common origin for all life)

• Code is redundant– several codons for each

amino acid– mutation insurance!

The mRNA code

Start codon AUG methionine

Stop codons UGA, UAA, UAG

TACGCACATTTACGTACGCGGDNA AUGCGUGUAAAUGCAUGCGCCmRNA

Pro

Ala

MetVal

Leu

Met

Transcription and Translation Builder http://learn.genetics.utah.edu/content/begin/dna/transcribe

/

ArgArg

You Transcribe and Translate a Gene!http://learn.genetics.utah.edu/content/begin/dna/

Step Through Translationhttp://bcs.whfreeman.com/thelifewire/content/chp12/1202003.html

1. Transcribe and Translate a Gene2. What makes a firefly glow?

DNA Translation Real Time and Interactive http://www.dnai.org/a/index.html

Transcription in Real Time (view as class) http://www.dnalc.org/resources/3d/TranscriptionBasic_withFX.htmll

Can you tell the story?

DNA

transcription

ribosome

tRNA

aminoacids

protein

translation

mRNA

29:08 Central Dogma Biologix__Translation_and_Protein_Synthesis

A Quick Review….

1. What is this molecule?

3.What is this process?

2.What is this molecule?

4.What is this structure?

8.What is this process?

6.What are these molecules?

5.What is this molecule?

7.What is this molecule?

DNA TAC GCA TGG AAT TAC GCA TGG AAT

Substitution/Point Mutation = one base is changed and one amino acid is changed.

Substitution/Point Mutation = one base is changed and one amino acid is changed.

mRNA AUG CGU ACC UUA AUG CAU ACC UUA

Protein Met Arg Thr Leu Met His Thr Leu

DNA TAC GCA TGG AAT TAC GTA TGG AAT

Insertion Mutation = one base is inserted and everything downstream is changed.

Insertion Mutation = one base is inserted and everything downstream is changed.

mRNA AUG CGU ACC UUA AUA GCA UAC CUU A

Protein Met Arg Thr Leu Ile Ala Tyr Leu

T

DNA TAC GCA TGG AAT TAT CGT ATG GAA T

http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_4.html

EXPLAIN DIVERSITY…

• Each organism has a unique sequence of DNA.• The DNA sequence determines the order of amino acids in the organism’s proteins.• The order of amino acids determines the shape that the protein made will take.• The shape of the protein determines what it can do.• What the protein does determines everything about the organism.• Gene Regulation determines when a sequence of DNA will be put to use and when it won’t.

Gene Regulation…Keeping Control!

Every species has its own number of chromosomes in

each cell.

OrganismNumber of

Chromosomes

Cat 32

Chimpanzee 48

Dog 78

Cow 60

Human 46

Horse 64

Pea plant 14

Corn plant 20

Mosquito 6

Honeybee 32

Sugarcane 80

Sand dollar 62

Notice:More is not always

better... Sometimes it’s just more.

Remember…a section on a chromosome that codes for a specific trait is called a GENE.

And…

There are lots and lots of genes on each chromosome!

The job of a gene is to control the production of proteins.

Not every gene is expressed (turned on) at the same time.

Gene Regulation = what controls when a gene is expressed and when it is not.

In bacteria, genes are in groups called Operons.

Example: E. coli that’s in our digestive system helps us break down milk.

Each Operon codes for a specific protein.

Baby features (birth – 5 yrs)

Child features (5 yrs – 12 yrs)

Teen features (12 yrs – 17 yrs)

Adult features (17 yrs – 60 yrs)

Elderly features (60 yrs – death)

RNA polymerase

Promoter Sequence = area “upstream”

(toward the 5’ end)

from the gene where the RNA polymerase

attaches.

Start Codon = set of three nucleotide bases

where transcription begins.

Stop Codon = set of three nucleotide bases

where transcription ends.

Terminator Sequence = area “downstream” from the gene where

the polymerase detaches.

Gene5’

3’

Lac operon

Are You Lactose Intolerant?

Here’s how we metabolize

milk…

Has to have a CAP to start.

Can NOT have a Repressor.

http://sumanasinc.com/

webcontent/animations/content/

lacoperon.html

Beadle and TatumOne gene, one protein.

Beadle and Tatum Experiment http://wps.prenhall.com/wps/media/objects/1552/1589869/web_tut/21_04/21_04_01a.swf

Gene Therapy: Introduction

What is Gene Therapy?

Using parts of a gene from a healthy cell to fix a damaged or sick cell.

How Gene Therapy

Works (Interactive)

http://www.edu365.cat/aulanet/comsoc/Lab_bio/simulacions/GeneTherapy/

GeneTherapy.htm

Don’t hate me because I’m beautiful…

Blame it on my GENES!

Any Questions?

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Assignment:Coach Book L15