Chapters 5.8 to 5.10 Gene Mutations

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Chapters 5.8 to 5.10Gene Mutations

• Ms. Doshi

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Gene Regulation

• Gene regulation or gene control depends on the
  environment.
• Prokaryotes
• The lac operon is an example of gene control in
  E.coli.
• Eukaryotes
• -use other mechanisms for positive or negative
  control.

3
The Lac Operon

• Promoter
• -RNA polymerase binds here.
• Operator
• -Repressor protein binds here
• Regulatory genes
• -code for repressor proteins that stop
  transcription OR activator proteins that speed up
  transcription.

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The Lac Operon in Action

• If there is no lactose
• the OPERON is OFF
• (genes are not transcribed)
• If there is lactose
• the OPERON is ON
• (genes are transcribed)
• The OPERON is OFF because E. coli is using
  glucose as its source of energy.
• The OPERON is ON because E. coli is using lactose
  as its source of energy because there is no
  glucose in the environment.

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Lac Operon

• http//www.youtube.com/watch?vJcKxOj6YZu4

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Gene Expression in Eukaryotes
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Questions

• Gene regulation or gene control depends on the
  _____________
• What is an example of gene control in
  prokaryotes?
• How do eukaryotes regulate their genes?
• What are the different parts of the lac operon?
• Is the lac operon on or off if there is glucose
  in the environment?
• Is the lac operon on or off if there is no
  glucose and there is lactose in the environment?
• Are genes transcribed if there is no glucose and
  there is lactose in the environment?
• Are genes transcribed if there is glucose in the
  environment?
• What are the mechanisms of regulating gene
  transcription in eukaryotes?
• What are the mechanisms of regulating gene
  post-transcription in eukaryotes?

8
Mutations

• Point Mutations
• nucleotide substitution
• nucleotide insertion
• nucleotide deletion
• Chromosomal Aberrations
• gene deletion
• gene relocation
• gene duplication

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Point Mutations

• Point Mutations
• Look at board and codon table.
• Nucleotide Substitution
• Nucleotide Insertion
• Nucleotide Deletion

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Chromosomal Aberrations
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Mutation Worksheet
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Why do we get mutations?

• Spontaneous Mutations
• -during DNA duplication
• Radiation-induced mutations
• -X-ray
• -UV
• -nuclear power plants
• Chemical-induced mutations
• -smoking

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Drinking Alcohol

• Fast Flushers

• Normal

• Can do two step process to breakdown alcohol to
  non-toxic molecules.
• Has specific enzyme for first step.
• Has specific enzyme for second step (aldehyde
  dehydrogenase)
• RESULT NO PROBLEM

• Can only do first step of process to break down
  alcohol to non toxic molecules.
• Has specific enzyme for first step.
• Does not have enzyme for second step (aldehyde
  dehydrogenase)
• Result ALCOHOL is TOXIC

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Drinking Alcohol-Quiz

• Fast Flushers

• Normal

• Has specific enzyme for first step.
• Result ALCOHOL is TOXIC

• Can do two step process to breakdown alcohol to
  non-toxic molecules.
• Has specific enzyme for first step.
• Has specific enzyme for second step (aldehyde
  dehydrogenase)
• RESULT NO PROBLEM

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From Mutation to Illness

1. A mutated gene codes for a non-functioning
   protein, example enzyme.
2. Enzyme cant catalyze reaction.
3. The amount of substrate increases in the body.
4. The large amount of substrate causes sickness or
   death.

16
A Study of Japanese and Asians

• Half of the population in Japan are fast
  flushers
• Sample size 1300 alcoholics in Japan
• Result
• Low incidence of alcoholism in Japan and other
  Asian people.
• There are less alcoholics in Japan and other
  Asian countries because many are fast flushers,
  so they are less likely to drink.

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Questions

• What are the 2 main types of mutations?
• What are the 3 kinds of point mutations?
• What are the 3 kinds of chromosomal aberrations?
• What are the 3 reasons of having mutations?
• How does a fast flusher breakdown alcohol?
• How can a person become ill from a mutation in an
  enzyme? HINT There are 4 steps.
• Why is there a low incidence of alcoholism in
  Japan or other Asian countries? Do you think this
  study is valid?

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Any Questions?Any Answers?

• Any Comments?