Do Now: (Challenge Extra Credit!) The Nucleus Do 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.

hydrophilic Since the oil is hydrophobic, this membrane has only ONE LAYER. Polar head groups on the outside, hydrophobic tails in the oil hydrophobic

The nucleus is a small sphere that holds all of a cell’s DNA.

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 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?

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