1. Cell Structure
Section 7.2

2. Objectives Describe the roll of the cell nucleus?
What are the functions of vacuoles, lysosomes and the cytoskeleton?
What organelles help make and transport proteins?
What does the cell membrane do?

3. Eukaryotic cells

4. The Nucleus
Contains all of the DNA m and with it the instructions for making everything that the cell needs
Nuclear pores allow material to move in and out of nucleus
Proteins, RNA and other molecules move
Chromosomes are found in the nucleus
Nucleolus – where ribosome assmebly begins

5. Organisms that store, clean up and support
Vacuole
Act as storage area for materials
Example – water, salt, protein and carbohydrates
Single central vacuole common in plants
Provide structure
Some smaller vacuoles found in some animal cells – rare
Some specialized vacuoles can pump excess water out of cells
Vesicle
Store and move materials between organelles
Also move material to and from cell surface

6. More organelles Lysosome Cytoskeleton Clean up crew – sell janitors
Filled with enzymes that break down macromolecules into constituent parts
More common in animal cells
Cytoskeleton
Network of protein filaments – maintain cell shape
Can also aid in transport of material
Can aid in cell movement
Flagella

7. Cytoskeleton continued…
Microfilaments
Threadlike structures made of protein called actin
Extensive tough, flexible framework
Assembly and disassembly allows amoebas and other cells to crawl
Microtubules
Hollow structures made of tubulins
Maintain shape
Assist in cell division
Form centrioles in animal cells
Help organize cell division
Form projections from surface that allow cells to swim

8. Building proteins Ribosomes Endoplasmic Reticulum
Ribosomes assemble proteins
Small particles of RNA and protein found in cytoplasm
Produce proteins by following instructions produced by DNA
More ribosomes = more protein synthesis
Endoplasmic Reticulum
Where lipids of the cell membrane are made – smooth ER
Rough ER has ribosomes stuck to surface – proteins for export
New proteins inserted into rough ER where they can be modified

9. Golgi apparatus Acts as sorting depot
Proteins are modified, sorted and packed for storage or released from cell
Made of Stack of flattened membrane

10. Capturing and releasing energy
Chloroplasts
Biology’s solar power plants
Where photosynthesis takes place
Capture solar energy and turn it into chemical energy
Mitochondria
Convert chemical energy from food into compounds more convenient for cell use
All mitochondria comes from your mother
Has it’s own DNA – descended from unique microorganisms

11. Cellular boundaries
All cells are surrounded by a barrier known as a cell membrane
Prokaryotes and plants also have an additional barrier – cell wall
Cell walls are outside of cell membrane
Porous enough for water, oxygen and CO2 to flow in and out of cell wall
Provide support
For examples, makes up wood

12. Cell membranes
Lipid by-layer, with water loving (hydrophillic) and water hating (hydrophobic) middle layer
Creates oily layer that makes it hard for water to enter or leave
Transport proteins allow passage of larger molecules