This document provides information on eukaryotic cell structure. It describes the main parts of eukaryotic cells as the cell membrane or wall, cytoplasm, and nucleus. It explains that plant, fungi, and bacterial cells have a cell wall, while animal cells have a cell membrane. The document also discusses the phospholipid bilayer structure of the cell membrane and how it allows substances to move in and out of cells through diffusion, facilitated transport, active transport, and endocytosis/exocytosis. Finally, it lists some common cell organelles like the nucleus, mitochondria, Golgi apparatus and describes their basic functions.

1. Chapter 4
Cell Structure

2. Eukaryotic Cell Structure
• Eukaryotic cells have 3 main areas
Cytoplasm
Nucleus
Cell Wall or
Membrane

3. And these parts are?...
• Cell wall (only found in plants, fungi, bacteria)
or cell membrane (in animal, plants, fungi and
bacteria): forms the outer layer
• Cytoplasm (or cytosol): is the goo that holds
the organelles
• Nucleus (which is bound by a nuclear
membrane): contains chromosomes

4. Cell Wall vs Cell Membrane
• Plants, bacteria and fungi have cell walls
• Animal cells do not
• BOTH have a cell membrane

5. Cell walls
• In plants, made of the polysaccharide
cellulose
• In bacteria, made of peptidoglycan (sugar
protein)
• Pepto = protein
• Glycan = sugar
• In fungi, made of chitin, a polysaccharide
similar to cellulose

6. Phospholipid bilayer
• Made of lipids and proteins, in a phospholipid
bilayer
• A phosopholipid has a glycerol backbone, one
phosphate group (-PO3
2-), and two fatty acids
• The phosphate group is hydrophilic (or polar)
• The fatty acids are hydrophobic or non-polar

7. Why I <3 my Phospholipid bilayer
• The alignment of the bilayer (head out tails in)
allows for the aqueous innards of the cell to
remain separate from the aqueous solution
they live in

8. Why I <3 my Phospholipid bilayer
• AND…the bilayer also allows for important
“stuff” to be incorporated into the cell
membrane

9. How substances cross the cell
membrane
• Simple diffusion
• Molecules move from high concentration to
low concentration

10. How substances cross the cell
membrane
• Facilitated diffusion
• Moves molecules down concentration gradient
without use of energy, with help of carrier
protein in cell membrane
• http://highered.mheducation.com/sites/0072495855/student_view0/chapter
2/animation__how_facilitated_diffusion_works.html

11. How substances cross the cell
membrane
• Active transport
• Move molecules against a gradient using
energy (ATP)

12. How substances cross the cell
membrane
• Bulk transport
• Moves large bulky items across membrane
o Endocytosis (into cell) and exocytosis (out of cell)
• Cell engulf item, creating a vesicle
• Phagocytosis (cell eating) and pinocytosis (cell
drinking)

13. How substances cross the cell
membrane

14. Osmosis
• Movement of water across a cell membrane
down concentration gradient
• Hypertonic – more particles outside the cell than
inside the cell, water moves out of the cell
• Hypotonic – fewer particles out of the cell than
inside the cell, water moves into cell
• Isotonic – same amount of particles in and out of
the ell, no net water movement

15. Osmosis

16. Movement of stuff in and out of cells
• This animations shows all movement within
cells, click on the link, then select main menu
to pick either active or passive transport
• http://www.northland.cc.mn.us/biology/biolo
gy1111/animations/active1.swf

17. Organelles and their functions
• Know this…

18. Organelles and their functions
Organelle Function
Vacuole Storage
Ribosomes Site of protein synthesis
Smooth ER System of membranes and tubes that transport substances
Rough ER ER with ribosomes bound to it
Ribosomes sysnthsize membrane proteins or secreted proteins
Golgi Apparatus Sorts and packages proteins from rough ER
Mitochondria Produce ATP for cell
Lysosomes Digest foreign substance and worn our organelles
Centrioles Help to form spindle during mitosis
Nucleus Control center, holds DNA
Nucleolus Site of ribosome synthesis
Cell membrane Outer membrane of cell, controls what goes in and out

19. Enzymes
• Are proteins that are used to catalyze a reaction
• They are not used up in the reaction, so they can
be reused
• Reactants bind to the enzymes active sites
• Enzymes are specific
• Molecules that help enzymes are coenzyme