DNA ReplicationDNA ReplicationVocabulary:Vocabulary:

Replication - Synthesis of an identical Replication - Synthesis of an identical copy of a DNA strand. copy of a DNA strand.

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In which cell organelle is DNA In which cell organelle is DNA replicated?replicated?

NucleusNucleus

When does DNA cell replication occur?When does DNA cell replication occur?

Before a cell divides Mitosis & MeiosisMitosis & Meiosis

When DNA replicates, it results in When DNA replicates, it results in __________ of the number of __________ of the number of chromosomes in a cell?chromosomes in a cell?

                               DNA DEOXYRIBONUCLEIC ACID

Is the blueprint of life (has the instructions for making an organism) established by James Watson and Francis Crick -codes for your genes -shape of a double helix -made of repeating subunits called nucleotides Nucleotide - consists of a sugar, phosphate and a base

Nitrogenous Bases

Adenine, Thymine, , Guanine, Cytosine or A, T, G, C

Nucleotides pair in a specific way

- called the Base-Pair Rule Adenine pairs to ThymineGuainine pairs to Cytosine

To make a copy of any thing, you To make a copy of any thing, you need an original or template.need an original or template.

DNA has the template build in.DNA has the template build in. Replication begins when the double Replication begins when the double

helix unzipping.helix unzipping. A enzyme breaks the __________ A enzyme breaks the __________

bonds in the DNA exposing the bonds in the DNA exposing the template.template.

If you know the sequence of base on one strand, If you know the sequence of base on one strand, you can predict the sequence on the other strand. you can predict the sequence on the other strand. (Base ? ___________)(Base ? ___________)

What is the sequence of nitrogen bases on the left side of the DNA molecule below?______________________________________________________________

  PredictPredict the sequence of nitrogen bases on the right side of the DNA molecule below?__________________________________________________________

http://www.eduref.org/Virtual/Lessons/Science/Genetics/GET0201.pdf

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HW Read Page 413-416 and answer pg 416 #7,12, 13,14 15 Q&A on LL

What are Genes?What are Genes?

What is The Genetic Code?What is The Genetic Code?

It is three adjacent nucleotides (“letters”) in It is three adjacent nucleotides (“letters”) in mRNA that specify an amino acid in a mRNA that specify an amino acid in a polypeptide, (_________) molecule.polypeptide, (_________) molecule.

Genes are areas on the DNA molecule Genes are areas on the DNA molecule that code for the synthesis of specific that code for the synthesis of specific proteins.proteins.

-Proteins determine the traits in organisms so Proteins determine the traits in organisms so

therefore, genes determine the specific traits of therefore, genes determine the specific traits of

an organism.an organism.

Protein SynthesisProtein Synthesis

Is a process whereby DNA encodes for the Is a process whereby DNA encodes for the production of amino acids and proteins.production of amino acids and proteins.

This process can be divided into two parts:This process can be divided into two parts:1. Transcription 1. Transcription 2. Translation2. Translation

VocabularyVocabularyTranscription - Synthesis of mRNA Transcription - Synthesis of mRNA Translation - Synthesis of polypeptide from amino acids. Translation - Synthesis of polypeptide from amino acids. Codon - Base triplet on mRNA. Codon - Base triplet on mRNA. Anticodon - Complementary triplet on tRNA. Anticodon - Complementary triplet on tRNA. Polypeptide - ______ moleculePolypeptide - ______ molecule

DNA is too large to leave the DNA is too large to leave the Nucleus, soNucleus, so

how does the information (genetic how does the information (genetic codes) within the DNA molecule get codes) within the DNA molecule get to the ribosome’s where proteins are to the ribosome’s where proteins are synthesized?synthesized?

An intermediate molecule is needed.An intermediate molecule is needed.

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RNA is that molecule.RNA is that molecule.

It is single stranded and It is single stranded and thus is smaller than thus is smaller than DNA & able to leave the DNA & able to leave the nucleus through the nucleus through the nuclear pores and carry nuclear pores and carry the codes to the the codes to the ribosomeribosome Uracil (U)* instead of Thymine (T)Uracil (U)* instead of Thymine (T)

NOTE:NOTE:

Uracil (U)* instead of Thymine (T) in the RNAUracil (U)* instead of Thymine (T) in the RNA

RNA DNA

PROTEIN SYNTHESISPROTEIN SYNTHESIS

Two parts:Two parts:

1. Transcription 1. Transcription 2. Translation2. Translation

Step 1 of Protein SynthesisStep 1 of Protein SynthesisTRANSCRIPTIONTRANSCRIPTION

One strand of the DNA double helix is used One strand of the DNA double helix is used as a template by the RNA polymerase to as a template by the RNA polymerase to synthesize a messenger RNA (mRNA). synthesize a messenger RNA (mRNA).

The mRNA then migrates from the nucleus The mRNA then migrates from the nucleus to the ribosome.to the ribosome.

The DNA molecule unzips /opens up on one side only and the base sequence is transcribed into a complementary sequence of bases transcribed into a complementary sequence of bases forming a mRNA molecule. forming a mRNA molecule. Remember Uracil (U)* instead of Thymine Uracil (U)* instead of Thymine (T)(T)WWhat will the sequence of bases in the mRNA? DNA Sequence (left side) __A C A____G G A______C G A______mRNA Sequence _________________________________________

 

What is a Codon?What is a Codon?

A sequence of three nucleotides that A sequence of three nucleotides that encode for an amino acid or signifies encode for an amino acid or signifies a start or stop signal.a start or stop signal.

NOTE*NOTE*

AUG = Start & Methionine Amino AcidAUG = Start & Methionine Amino Acid

UAA = StopUAA = Stop

The Genetic CodeThe Genetic Code

Codons contCodons cont

There are 64 possible codons There are 64 possible codons corresponding to 20 amino acids.corresponding to 20 amino acids.

NOTE * The Start codon corresponds NOTE * The Start codon corresponds to the amino acid methionine and the to the amino acid methionine and the stop codon have no amino acids stop codon have no amino acids attached.attached.

Step 2 of Protein SynthesisStep 2 of Protein SynthesisTranslationTranslation

- - What is it?What is it?

The coded information The coded information flows from the DNA to the ribosome flows from the DNA to the ribosome via the mRNA and then tRNA brings via the mRNA and then tRNA brings the corresponding amino acid.the corresponding amino acid.

Where does it take place?Where does it take place?

RibosomeRibosome

2. Translation2. Translation

Steps in TranslationSteps in Translation(1)(1)Initiation Initiation (2)(2) Elongation Elongation (3)(3) TerminationTermination

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(1) Initiation (1) Initiation The ribosome binds The ribosome binds to the mRNA at the to the mRNA at the start codonstart codon

(_____) that is recognized only by the (_____) that is recognized only by the initiator tRNA. initiator tRNA.

Step 1. Initiation______Step 1. Initiation______

Step 2. ElongationStep 2. Elongation whereby the correct amino acid is brought whereby the correct amino acid is brought

to the ribosome and a peptide bond forms to the ribosome and a peptide bond forms between adjacent amino acids and the between adjacent amino acids and the entire assembly moves one position along entire assembly moves one position along the mRNA. the mRNA.

The polypeptide chain continues to grow..The polypeptide chain continues to grow..

Step 3. TerminationStep 3. Termination Termination Termination which happens when a stop which happens when a stop

codon is reached, there is no amino acid to codon is reached, there is no amino acid to be incorporated and the entire assembly be incorporated and the entire assembly dissociates to release the newly-dissociates to release the newly-synthesized polypeptide.synthesized polypeptide.

What are the stop codons?What are the stop codons?__________________________

SUMMARYSUMMARY

SummarySummary- Information flows from DNAInformation flows from DNARNARNAProteinsProteins- RNA serves as the intermediary between RNA serves as the intermediary between

DNA and proteins.DNA and proteins.- There are three types of RNA. mRNA, rRNA There are three types of RNA. mRNA, rRNA

and tRNA.and tRNA.- The Genetic Code represents 64 possible The Genetic Code represents 64 possible

codons corresponding to 20 different amino codons corresponding to 20 different amino acids, start signal and stop signals.acids, start signal and stop signals.

- The process of TRANSLATION takes place The process of TRANSLATION takes place within the cytoplasm on a ribosome.within the cytoplasm on a ribosome.

- The process of TRANSLATION involves: The process of TRANSLATION involves: initiation, elongation and termination.initiation, elongation and termination.

In what cell organelle are proteins In what cell organelle are proteins synthesized ?synthesized ?

Ribosome'sRibosome'sWhich cell organelle controls the Which cell organelle controls the manufacture of proteins in the manufacture of proteins in the ribosome?ribosome?

NucleusNucleusWhat is in the nucleus contains the information for protein synthesis

• DNA

20 AMINO ACIDS

There are twenty amino acids required for human life to exist. Adults have eight essential amino acids that they cannot synthesize. The other twelve can be produced within our bodies.

AlanineArginineAsparagineAspartic AcidCysteineGlutamic AcidGlutamineGlycineHistidineIsoleucine

LeucineLysineMethioninePhenylalanineProlineSerineThreonineTryptophanTyrosineValine

Essential amino acids histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

What in the nucleus controls cell activities?What in the nucleus controls cell activities?

The information within the DNA The information within the DNA molecule is encoded within the molecule is encoded within the sequence of the nitrogenous bases.sequence of the nitrogenous bases.

What in the nucleus contains the codes for What in the nucleus contains the codes for protein synthesis? protein synthesis?

Answer: The DNA