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The NucleusDo Now: (Challenge Extra Credit!)
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.
hydrophobic
hydrophilic
Since the oil is hydrophobic, this membrane has only ONE LAYER. Polar head groups on the outside, hydrophobic tails in the oil
The nucleus is a small sphere that holds all of a cell’s DNA.
The Nucleus
Structure & Function
• Structure: spherical lipid membrane (like cell membrane) that contains DNA.
• Function: Stores DNA, controls cell activity
It is found ONLY in EUKARYOTIC cells.
Dolly the SheepDolly 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?
When adult animals are cloned, it is by adding a nucleus
from a cell to a new egg cell without a nucleus.
How to Make a Sheep.
nuclear envelope: A lipid bilayer that surrounds the
nucleus
nuclear pores: openings in the
nuclear envelope
Most of the inside of a nucleus is made up of chromatin, which is a mix of DNA
and related proteins.
The nucleolus is a small dark part inside a nucleus where ribosomes are
made.
Find those parts:
Nuclear Envelope
Nuclear Pores
Chromatin
Nucleolus
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
Homework… read all about it!
• “Nucleus” p. 81 , SR #3 p. 83