Protein SynthesisProtein Synthesis

DNA ReviewDNA Review

The nucleotide bases will The nucleotide bases will point to the inside of the point to the inside of the DNA molecule while the DNA molecule while the outside (backbone) of the outside (backbone) of the DNA molecule will be made DNA molecule will be made of the sugar and phosphate of the sugar and phosphate moleculesmolecules

When complete the DNA When complete the DNA molecule forms a double molecule forms a double helix (two spiral sides helix (two spiral sides wrapped together)wrapped together)

CHROMOSOMES CONTAIN CHROMOSOMES CONTAIN DNADNA

The nucleus contains The nucleus contains chromatinchromatin

Chromatin is made of smaller Chromatin is made of smaller nucleosomesnucleosomes

A nucleosome is formed by a A nucleosome is formed by a DNA molecule wrapped DNA molecule wrapped around a protein “stick”around a protein “stick”

Looks like cotton candy Looks like cotton candy wrapped around the paper wrapped around the paper conecone

Protein SynthesisProtein Synthesis

Why is it important?Why is it important?

Cells are controlled by enzymes- Cells are controlled by enzymes- enzymes are proteinsenzymes are proteins

Almost every substance made by the cell Almost every substance made by the cell is or contains a stuctural proteinis or contains a stuctural protein

VocabularyVocabulary GeneGene- a portion of DNA that codes for a protein- - a portion of DNA that codes for a protein-

the “recipe” for a proteinthe “recipe” for a protein mRNAmRNA- messenger RNA- messenger RNA tRNAtRNA- transfer RNA- transfers amino acids- transfer RNA- transfers amino acids CodonCodon- mRNA’s complementary trio of bases- mRNA’s complementary trio of bases AnticodonAnticodon- tRNA’s complementary trio of bases- tRNA’s complementary trio of bases TranscriptionTranscription- mRNA making a template of - mRNA making a template of

DNA’s codeDNA’s code TranslationTranslation- tRNA “reading” mRNA’s code and - tRNA “reading” mRNA’s code and

transferring the amino acids necessary to form a transferring the amino acids necessary to form a proteinprotein

Two Steps to Protein Two Steps to Protein SynthesisSynthesis TranscriptionTranscription- takes place in - takes place in

the nucleus-mRNA makes the nucleus-mRNA makes template of DNA’s codetemplate of DNA’s code

TranslationTranslation- takes place on - takes place on the ribosome in the the ribosome in the cytoplasm- tRNA transfers cytoplasm- tRNA transfers amino acidsamino acids

Things to RememberThings to Remember

DNA contains the “recipes” for proteins- DNA contains the “recipes” for proteins- called genescalled genes

DNA is made of the bases adenine, DNA is made of the bases adenine, thymine, guanine and cytosinethymine, guanine and cytosine

A-T and C-GA-T and C-G RNA is made of the bases adenine, RNA is made of the bases adenine,

uracil, guanine and cytosineuracil, guanine and cytosine A-U and C-GA-U and C-G

TranscriptionTranscription

Takes place in the nucleusTakes place in the nucleus DNA unzipsDNA unzips mRNA makes a template of the DNA mRNA makes a template of the DNA

codecode mRNA copies the code three bases at a mRNA copies the code three bases at a

time- this is a time- this is a codoncodon

TranscriptionTranscription- mRNA - mRNA forms codonsforms codons

Translation- on the Translation- on the ribosome, tRNA transfers ribosome, tRNA transfers amino acidsamino acids

Another LookAnother Look

Another ViewAnother View

The four bases can combine in The four bases can combine in 64 different triplicate (codon) 64 different triplicate (codon) combinationscombinations

Each codon codes Each codon codes for a specific amino for a specific amino acidacid

Codon ChartCodon Chart

Another Codon ChartAnother Codon Chart

Protein StructureProtein Structure

A Few of The Finished A Few of The Finished Products! ProteinsProducts! Proteins

Think About It-Think About It-

LettersLetters→ Words→ Sentences→ Words→ Sentences

Sam hit the ball.Sam hit the ball. Bases→ Amino Acids→ ProteinsBases→ Amino Acids→ Proteins

View It!View It!

http://www.wisc-online.com/objects/index_tj.asp?objID=AP1302

http://www.pbs.org/wgbh/aso/tryit/dna/shockwave.html

Wrap UpWrap Up 1. DNA message is transcribed into messenger 1. DNA message is transcribed into messenger

RNA (mRNA)RNA (mRNA) 2. mRNA leaves the nucleus and attaches to a 2. mRNA leaves the nucleus and attaches to a

ribosomeribosome 3. Each three letter codon will attract a matching 3. Each three letter codon will attract a matching

three letter anti-codon of transfer RNA (tRNA) three letter anti-codon of transfer RNA (tRNA) 4. Each tRNA is carrying an amino acid “on its 4. Each tRNA is carrying an amino acid “on its

back”back” 5. As the tRNA molecules line up, their amino 5. As the tRNA molecules line up, their amino

acids also line upacids also line up 6. As the amino acids are lined up, they 6. As the amino acids are lined up, they

chemically bond to form a proteinchemically bond to form a protein

Mutations- Any error in the Mutations- Any error in the genetic codegenetic code

Can happen when:Can happen when: DNA is making new copies of itself DNA is making new copies of itself

(replication)(replication) DNA is being used to make messenger DNA is being used to make messenger

RNA (transcription)RNA (transcription) Transfer RNA is being attracted to the Transfer RNA is being attracted to the

messenger RNA at the ribosome messenger RNA at the ribosome (translation)(translation)

Types of MutationsTypes of Mutations

Point mutations happen when Point mutations happen when one or two bases are different one or two bases are different than they are supposed to bethan they are supposed to be

Frameshift mutations happen Frameshift mutations happen when extra bases are added or when extra bases are added or deleted deleted