ap biology discussion notes monday 10/6/2014. questions?? ask!!! if you have questions about any of...
TRANSCRIPT
Questions?? ASK!!!
• If you have questions about any of the content, notes, discussion or images be sure to ASK!!
• Reach Ms. Jacobs by e-mail: [email protected]
Goals for the Day
1. Become familiar with the cell organelles and their functions.
2. Be able to describe the function of specific organelles, and which types of organisms have them
3. Describe how things are transported in/out of the cell
Question of the Day
What cell part produces lipids and why is that so important?
Lipids make up EVERY membrane from our cell membrane to all of the membranes that surround Eukaryotic cell organelles (Ex. Mitochondria)
Functions of Smooth ER
• The smooth ER–Synthesizes lipids–Metabolizes carbohydrates–Detoxifies drugs and poisons–Stores calcium ions
Let’s think more about cells….
What is the typical size of a cell (generally)?
Why do you think this is?
Are there exceptions (cells that are a different size)?
Why cells are SO small
• Metabolic requirements set upper limits on the size of cells
• The surface area to volume ratio of a cell is critical
• As the surface area increases by a factor of n2, the volume increases by a factor of n3
• Small cells have a greater surface area relative to volume
Why cells are SO small
• So……..basically cells need to be small so that they can move things in and out efficiently.
• If we were one giant cell we couldn’t use diffusion to get the nutrients we need into and the wastes we don’t out of the cell.
Surface area increases whiletotal volume remains constant
Total surface area[sum of the surface areas(height width) of all boxsides number of boxes]
Total volume[height width length number of boxes]
Surface-to-volume(S-to-V) ratio[surface area volume]
5
6 150 750
1
1251251
1.26 6
Figure 6.7
Why aren’t cells infinitely small?
• We still need some cell parts inside of there!
• If this is really what limits how small a cell can be, which would you expect to be smaller: Prokaryotic or Eukaryotic cells?
How big is a (typical) cell?
• See if you’re right!
• Cell Size
Passive TransportWITH the GradientNO ATP NEEDED!!!
DiffusionOsmosis
--hypo, hyper, isotonic--turgor pressure--cytolysis--plasmolysis
Facilitated Diffusion (channel/carrier proteins)
Fluid-Mosaic Model of the Plasma Membrane
Surround cytoplasm; regulates what enters/leaves; semi-permeable; phospholipid bilayer
Figure 6.11a
Smooth ER
Rough ER
CisternaeRibosomes
Transport vesicle
Transitional ER
Nuclearenvelope
ER lumen
Functions of Smooth ER
• The smooth ER–Synthesizes lipids–Metabolizes carbohydrates–Detoxifies drugs and poisons–Stores calcium ions
Functions of Rough ER• The rough ER
– Has bound ribosomes, which secrete glycoproteins (proteins covalently bonded to carbohydrates)
– Distributes transport vesicles, proteins surrounded by membranes
– Is a membrane factory for the cell
• The Golgi apparatus consists of flattened membranous sacs called cisternae
• Functions of the Golgi apparatus– Modifies products of the ER– Manufactures certain macromolecules– Sorts and packages materials into transport
vesicles
The Golgi Apparatus: Shipping and
Receiving Center
Figure 6.12
cis face(“receiving” side ofGolgi apparatus)
trans face(“shipping” side ofGolgi apparatus)
0.1 m
TEM of Golgi apparatus
Cisternae
Lysosome
• Lysosomes- small, spherical organelles that contain the cell’s digestive enzymes
• Function: Digestion & Recycling
(The garbage man of the cell)
Species of the day 10/6
Curculio spp.
• Acorn Weevil
Species of the day 10/6
Curculio spp.
• Acorn Weevil
Do the acorn and the weevil share the same cell parts? EXPLAIN your answer!