1. Organelles – Part I

2. Organelles Organelles are ‘tiny organs.’
Organs are to humans as organelles are to cells.

3. Nucleus Function: The nucleus is the cell’s genetic control center.
Stores DNA
Makes RNA
Makes ribosomes
Directs the synthesis of proteins

4. Nucleus Structure: The nucleus has 3 parts:
Nuclear envelope – membrane surrounding genetic material
DNA
Chromatin: DNA stretched out and skinny
Chromosomes: DNA coiled up for replication
Nucleolus – center of nucleus, produces ribosomes

5. Nucleus
Chromatin
Nucleolus
Pore
Ribosomes
Rough endoplasmic reticulum
Two membranes of nuclear envelope

6. Ribosomes Function: Structure:
Ribosomes manufacture proteins based on instructions they get from the DNA in the nucleus.
Structure:
Ribosomes are small spherical structures.
They float in the cytoplasm OR are connected to the rough ER.
They are composed of proteins & RNA.

7. Ribosomes

8. Endoplasmic Reticulum (ER)
There are two types of ER:
Smooth ER
Rough ER

9. Smooth ER Function: Structure:
The smooth endoplasmic reticulum has a variety of functions:
Synthesizes lipids
Processes toxins and drugs in liver cells
Stores and releases calcium ions in muscle cells
Structure:
Smooth endoplasmic reticulum is composed of flattened sacs that often extend throughout the entire cytoplasm

10. Rough ER Function: Structure: The rough ER has three functions:
Synthesis of proteins (in the attached ribosomes)
Modification of proteins.
Packing of proteins.
Structure:
Rough endoplasmic reticulum is the same as the smooth but it is dotted with ribosomes which make it bumpy.

12. Golgi Apparatus (Golgi Bodies)
Function:
They receive and modify ER products then modify, sort, package and ship them to other organelles or the cell surface.
Structure:
The Golgi apparatus looks like stacks of membranous sacs.

14. Lysosomes Function: Structure: They contain enzymes that break down:
Food
Damaged organelles
Bacteria with which they fuse.
Structure:
Lysosomes are made by the Golgi Apparatus.
They are tiny spheres of enzymes

16. Interesting Facts… Abnormal lysosomes can cause fatal diseases.
When a cell is damaged the nucleus sends a message to the lysosome telling it to explode – the enzymes inside eat the cell – for this reason we also call lysosomes ‘suicide sacs’

17. Huntingdon’s disease

18. Pompe’s disease

19. Tay-sachs disease

20. Vacuoles Function: Vacuoles can do all kinds of things.
They can contain pigment (color)
They can contain poison.
They have contain food or water.
Plants have central vacuoles that function store large amounts of water

21. Vacuoles
Structure:
Vacuole is the general term given to any other membrane sac in the cell.
Animal cells have small vacuoles called vesicles