Ch. 10 Notes DNA: Transcription and Translation. GOALS Compare the structure of RNA with that of DNA Summarize the process of transcription Relate.

Ch. 10 NotesDNA: Transcription and

Translation

Ch. 10 NotesDNA: Transcription and

Translation

GOALSGOALS

Compare the structure of RNA with that of DNA Summarize the process of transcription Relate the role of codons to the sequence of

amino acids that results after translation Outline the major steps of translation Discuss the evolutionary significance of the

genetic code Describe how the lac operon is turned on or off Summarize the role of transcription factors in

regulating eukaryotic gene expression Describe how eukaryotic genes are organized Evaluate three ways that point mutations can

alter genetic material

Compare the structure of RNA with that of DNA Summarize the process of transcription Relate the role of codons to the sequence of

amino acids that results after translation Outline the major steps of translation Discuss the evolutionary significance of the

genetic code Describe how the lac operon is turned on or off Summarize the role of transcription factors in

regulating eukaryotic gene expression Describe how eukaryotic genes are organized Evaluate three ways that point mutations can

alter genetic material

Decoding the Information in DNA

RNARNA 1. Nucleic acid made of nucleotides linked together

2. Single stranded

1. Nucleic acid made of nucleotides linked together

2. Single stranded

RNARNA 3. Contains 5C ribose sugar (one more oxygen than DNA)

3. Contains 5C ribose sugar (one more oxygen than DNA)

• RNA • 4. Has A, G and C bases, but no T

• 5. Thymine replaced by uracils (which pairs with adenine)

Transcription

Instructions for making protein are transferred from a gene to an RNA molecule

Translation

Two types of RNA are used to read instructions on RNA molecule and put amino acids together to make the protein

Gene Expression

Protein synthesisProtein making process

based on information encoded in DNA

Protein synthesisProtein making process

based on information encoded in DNA

TRANSCRIPTIONTRANSCRIPTION

Transcription

Transfers info from a gene on DNA to RNA

In prokaryotes- occurs in cytoplasm

In eukaryotes- occurs in nucleus

Transfers info from a gene on DNA to RNA

In prokaryotes- occurs in cytoplasm

In eukaryotes- occurs in nucleus

Transcription(STEPS)

1. RNA polymerase binds to start signal “promoter” on DNA

2. RNA polymerase unwinds and opens DNA double helix

1. RNA polymerase binds to start signal “promoter” on DNA

2. RNA polymerase unwinds and opens DNA double helix

3. RNA polymerase reads genes- adds and links matching nucleotides by base pairing (A-U and G-C)

4. RNA polymerase reaches stop signal at end of gene

5. As RNA polymerase works, a single strand of RNA grows

4. RNA polymerase reaches stop signal at end of gene

5. As RNA polymerase works, a single strand of RNA grows

6. DNA helix zips itself back up as RNA polymerase passes by

7. Many identical RNA molecules are made simultaneouslyFeather like appearance in

photos

7. Many identical RNA molecules are made simultaneouslyFeather like appearance in

photos

The GENETIC CODEThe GENETIC CODE

Messenger RNA

mRNA Made when cells need a

protein madeDelivers protein making

instructions from gene to translation site

Instructions written in codons

mRNA Made when cells need a

protein madeDelivers protein making

instructions from gene to translation site

Instructions written in codons

CodonsCodons Three nucleotide sequences along mRNA

64 possible codonsEach corresponds to:

An amino acid ORA stop signal ORA start signal

Three nucleotide sequences along mRNA

64 possible codonsEach corresponds to:

An amino acid ORA stop signal ORA start signal

Can You Tell Me?Can You Tell Me?

1. During DNA replication, what molecule “reads” the strand of DNA to make the matching strand?

2. During transcription, what molecule “reads” the DNA?

3. What material does the transcription process create?

1. During DNA replication, what molecule “reads” the strand of DNA to make the matching strand?

2. During transcription, what molecule “reads” the DNA?

3. What material does the transcription process create?

The GENETIC CODE

• RNA’s role in translation

• Takes place in cytoplasm• Transfer RNA (tRNA) and

ribosomes help in protein synthesis

Transfer RNA

tRNA Single strand, carries

amino acidFolded shapeContains anticodon

tRNA Single strand, carries

amino acidFolded shapeContains anticodon

AnticodonAnticodon 3 nucleotides on tRNA that are complementary to a mRNA codon

3 nucleotides on tRNA that are complementary to a mRNA codon

Ribosomal RNA

rRNA makes up part of ribosomes

Translation process

1. mRNA leaves nucleus, enters cytoplasm

2. Ribosome hooks onto mRNA at start codon

1. mRNA leaves nucleus, enters cytoplasm

2. Ribosome hooks onto mRNA at start codon

Translation process

3. tRNA attaches to ribosome subunit and binds to mRNAAnticodon of tRNA binds to

codon of mRNA

3. tRNA attaches to ribosome subunit and binds to mRNAAnticodon of tRNA binds to

codon of mRNA

Translation process

4. tRNA drops off amino acid its carrying

5. Another tRNA comes and drops an amino acid off

4. tRNA drops off amino acid its carrying

5. Another tRNA comes and drops an amino acid off

Translation process

6. Another tRNA enters, first tRNA leaves

Translation process

7. Each amino acid bonded to previous one to form a chain

8. tRNA detaches leaving

amino acid attached to

remaining tRNA

7. Each amino acid bonded to previous one to form a chain

8. tRNA detaches leaving

amino acid attached to

remaining tRNA

Translation process

9. Repeats until ribosomal subunit reaches stop codon

10. Newly made protein is released

9. Repeats until ribosomal subunit reaches stop codon

10. Newly made protein is released

TRANSLATIONTRANSLATION

TRANSLATION

TRANSLATIONTRANSLATION

Assessment OneAssessment One

Distinguish two differences between RNA structure and DNA structure

Explain how RNA is made during transcription

Interpret the genetic code to determine the amino acid coded for by the codon CCU

Compare the roles of the three different types of RNA during translation

What is the maximum number of amino acids that could be coded for by a section of mRNA with the sequence GUUCAGAACUGU?

Distinguish two differences between RNA structure and DNA structure

Explain how RNA is made during transcription

Interpret the genetic code to determine the amino acid coded for by the codon CCU

Compare the roles of the three different types of RNA during translation

What is the maximum number of amino acids that could be coded for by a section of mRNA with the sequence GUUCAGAACUGU?

Protein SynthesisProtein Synthesis

Protein Synthesis in Prokaryotes

Requires too much energy and too many materials for cell to make every protein encoded for by the DNA at all times

Gene expression can be regulated according to cell needs

Ex: E. coli bacteria

Requires too much energy and too many materials for cell to make every protein encoded for by the DNA at all times

Gene expression can be regulated according to cell needs

Ex: E. coli bacteria

Regulating Protein Synthesis

Lac Operon

1. Lactose in dairy products enters your intestines

2. E. coli there can use lactose for nutrition (to make glucose and galactose)

1. Lactose in dairy products enters your intestines

2. E. coli there can use lactose for nutrition (to make glucose and galactose)

• Lac Operon

• 3. Three genes for breaking down lactose located next to each other on DNA (can turn them on or off)– Genes on: they’re ready to be

transcribed and translated

Lac Operon

4. These 3 genes turn on in presence of lactose and turn off in its absence

Lac Operon

5. Operator- area on DNA (touching start/promoter) that acts as on and off switchCan block RNA polymerase

from transcribing

5. Operator- area on DNA (touching start/promoter) that acts as on and off switchCan block RNA polymerase

from transcribing

Lac Operon

6. Operon consists of Operator PromoterThree genesAll work together to

control lactose metabolism

6. Operon consists of Operator PromoterThree genesAll work together to

control lactose metabolism

Lac Operon

7. No lactose presentLac operon is turned off when

repressor protein binds to DNARepressor blocks RNA

polymerase from binding

7. No lactose presentLac operon is turned off when

repressor protein binds to DNARepressor blocks RNA

polymerase from binding

Lac Operon

8. In presence of lactoseLactose binds to repressor

changing its shapeCauses repressor to fall off

DNAAllows RNA polymerase to bind

and transcribe

8. In presence of lactoseLactose binds to repressor

changing its shapeCauses repressor to fall off

DNAAllows RNA polymerase to bind

and transcribe

Protein synthesis in eukaryotes

Most gene regulation is to control the onset of transcription (binding of RNA polymerase)

Protein synthesis in eukaryotes

Transcription Factors- regulatory proteins that help rearrange RNA polymerase into the correct position

Intervening DNAIntervening DNA

Intervening DNA in Eukaryotic Genes

1. Introns- longs segments of nucleotides with no coding informationBreak up DNA/genes

2. Exons- actual genes that are translated into proteins

3. After transcription, introns in mRNA are cut out by spliceosomesExons are stitched back

together

3. After transcription, introns in mRNA are cut out by spliceosomesExons are stitched back

together

4. Large numbers of exons and introns allows evolutionary flexibility because they can be shuffled about to make new genetic codes

MutationsMutations

MutationsMutations Changes in DNA of a gene are rare

When in body cells, only affect individual

When in gametes, offspring can be affected

Changes in DNA of a gene are rare

When in body cells, only affect individual

When in gametes, offspring can be affected

MutationsMutations

MutationsMutations A. Gene rearrangements- entire gene moved to a new location (disrupts its function)

A. Gene rearrangements- entire gene moved to a new location (disrupts its function)

MutationsMutations

MutationsMutations B. Gene alterations- changes a geneUsually results in wrong amino

acid being hooked into protein (disrupts protein function)

B. Gene alterations- changes a geneUsually results in wrong amino

acid being hooked into protein (disrupts protein function)

MutationsMutations

MutationsMutations C. Point Mutation- single nucleotide changes

C. Point Mutation- single nucleotide changes

MutationsMutations

MutationsMutations D. Insertion Mutation- extra piece of DNA is inserted

D. Insertion Mutation- extra piece of DNA is inserted

MutationsMutations

MutationsMutations E. Deletion Mutation- segments of gene are lost

E. Deletion Mutation- segments of gene are lost

MutationsMutations

MutationsMutations F. Frame shift Mutations- causes gene to be read in wrong 3 nucleotide sequenceEx THE CAT ATE Remove CTHE ATE TE (makes no sense)

F. Frame shift Mutations- causes gene to be read in wrong 3 nucleotide sequenceEx THE CAT ATE Remove CTHE ATE TE (makes no sense)

WEBSITESWEBSITES DNA Workshop Transcription Interactive Transcribing and Translating a Gene

Protein Synthesis Animation Transcription Animation Translation Movie Protein Translation Animation Animation of Translation Protein Synthesis Movie Transcription Game Protein Synthesis Tutorial

DNA Workshop Transcription Interactive Transcribing and Translating a Gene

Protein Synthesis Animation Transcription Animation Translation Movie Protein Translation Animation Animation of Translation Protein Synthesis Movie Transcription Game Protein Synthesis Tutorial

Ch. 10 Notes DNA: Transcription and Translation. GOALS Compare the structure of RNA with that of DNA Summarize the process of transcription Relate.

dna rna

dna slide

rna polymerase

dna transcription instructions

process of transcription

rna molecule slide

dna translation

structure of rna

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