The Nucleus

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The Nucleus

• Do Now Take out homework, then
• Challenging Extra Credit Do Now
• The cells of plant seeds store oils in
  the form of droplets enclosed by membranes.
  These membranes are very different from the cell
  membrane even though they are made of the same
  phospholipids.
• Draw a simple model for a membrane
  around an oil droplet, and briefly explain why
  this arrangement is more stable than bilayer.

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hydrophobic
hydrophilic
Since the oil is hydrophobic, this membrane has
only ONE LAYER. Polar head groups on the
outside, hydrophobic tails in the oil
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The nucleus is a small sphere that holds all of a
cells DNA.
The Nucleus
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Structure Function

• Structure spherical lipid membrane (like cell
  membrane) that contains DNA.
• Function Stores DNA, controls cell activity

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It is found ONLY in EUKARYOTIC cells.
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Dolly the Sheep
Dolly was the first clone of an adult mammal ever
made. Dolly was born in 1997, she died a few
years later, younger than usual for a sheep. So
what does a cloned sheep have to do with a cell
nucleus?
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When adult animals are cloned, it is by adding a
nucleus from a cell to a new egg cell without a
nucleus.
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How to Make a Sheep.
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nuclear envelope A lipid bilayer that surrounds
the nucleusnuclear pores openings in the
nuclear envelope
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Most of the inside of a nucleus is made up of
chromatin, which is a mix of DNA and related
proteins.
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The nucleolus is a small dark part inside a
nucleus where ribosomes are made.
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Find those parts Nuclear Envelope Nuclear
Pores Chromatin Nucleolus
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SUPER IMPORTANT CELL PARTS NUCLEUS

• STRUCTURE Sphere in the center of a cell that
  contains all of the DNA
• FUNCTION Controls cell functions stores
  genetic information

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Homework read all about it!

• Nucleus p. 81 , SR 3 p. 83