1. Cell Organelles: Nucleus & Ribosomes
Chapter 6; 6.3; Pgs
Objective: I can describe the function and parts of the nucleus, DNA, and ribosomes. I can also distinguish between a nucleus and a nucleolus

2. Nucleus: control center of cell
A “ball” containing DNA (type of organelle)
Surrounded by a double membrane called
Nuclear envelope  thus, nucleus is
Holes to allow only certain materials to pass
Nuclear pores
Allows: proteins, RNA (not DNA)

3. DNA organized into…
Chromosome – DNA (with proteins) wound tightly/condensed into structure
Only during cell division
Easier to move around
Chromatin – DNA (with proteins) unorganized and tangled
“Invisible cloud”
Normal & accessible
Chromosome made of chromatin

4. Chromatin vs. Chromosomes

5. Nucleolus – not an organelle
Dark region of nucleus (part/structure)
Makes ribosomes (specifically – rRNA)
Picture Time! Labeling Diagrams!

7. Difficulty with Nucleus diagrams
Is it the nucleus or is it the entire cell?

8. Difficulty with Nucleus diagrams
What are you pointing at?
Nuclear envelope
Chromatin (DNA)
Nucleolus
Entire purple structure = nucleus

9. Chromatin (DNA)
Nuclear envelope
Nucleolus
Nucleus
Nuclear pore

10. Ribosomes – not an organelle…?
Semantic arguments:
Made of RNA + proteins
Specifically, ribosomal RNA (rRNA)
Function: synthesizes (makes) protein
Tiniest structure (dots in pictures)

11. Ribosome Types Free ribosomes suspended in cytosol
Bound ribosomes attached to nuclear envelope or endoplasmic reticulum

12. Ribosome Types Make Protein
Free make protein for within cell (cytosol)
Bound make protein for secretion outside cell (or for within other orgnels)