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2005-2006AP Biology
Chapter 7.
The Cell:Nucleus, Ribosomes
2005-2006AP Biology
Nucleus Function
contains eukaryoticcell’s genetic library most genes in nucleus some genes located in
mitochondria &chloroplasts
Size ~ 5 microns (µm)
in diameter
2005-2006AP Biology
Nucleus structure Structure
separated from cytoplasm by a doublemembrane, nuclear envelope
double membrane is fused in spotsforming pores allows large macromolecules
& particles to pass through
What kind of moleculesneed to pass through?
2005-2006AP Biology
2005-2006AP Biology
2005-2006AP Biology
Nucleus structure Within nucleus, DNA organized into
fibrous material, chromatin in normal cell appears as diffuse mass
When cell preparesto divide, chromatinfibers coil up asseparate structures,chromosomes
2005-2006AP Biology
Nucleus structure Densely stained region
= nucleolus Function
production ofribosomal subunitsfrom rRNA & proteins pass through
nuclear pores tocytoplasm &combine to formribosomes
2005-2006AP Biology
2005-2006AP Biology
2005-2006AP Biology
Ribosomes Function
protein production Structure
ribosomes contain rRNA & protein composed of 2 subunits that combine to carry
out protein synthesis
2005-2006AP Biology
Types of Ribosomes Free ribosomes
suspended in cytosol synthesize proteins that
function within cytosol Bound ribosomes
attached to outside ofendoplasmic reticulum
synthesize proteins forexport or for membranes
2005-2006AP Biology
Ribosomes Prokaryotes & eukaryotes have
different ribosomes different size subunits different proteins can this difference be useful?
2005-2006AP Biology
Prokaryote vs. eukaryote ribosomes
2005-2006AP Biology
Any Questions??