Tuesday, October 4, 2011

Oct. 3, 2011

Today we finished the notes on the cytoskeleton and began notes on the cell membrane. There is a quiz tomorrow on everything we've learned so far in the section. There is also a lab tomorrow. The homework is to read pages 37-39 in our UP and draw a picture of the lab.

Here are some basic overviews of what we learned.

Intermediate Filaments

  • ropelike protiens
  • anchor organelles


  • straight, hollow tubes made of protiens called tubulins
  • provide rigity and shape to the cell
  • tracks for organelle movement
  • guide chromosome movement in cell division
  • move cilia and flagella

Cilia-propel protists

Flagella-propel some types of cells, long "tail"

Microtubule structure

  • form a 9+2 arrangementto
  • to move cilia or flagella, dyniens grap onto an adjacent microtubule doublet
  • basal bodies and centrioles have identical structures

Plasma Membrane

membranes of a cell

  • plasma membrane-outer membrane
  • endomembranes-smooth and rough ER, golgi, vacuole,lysosome
  • membraneous envelope-nucleus chloroplast mitochondria

membrane features

  • semi-permeable, allow some substances to pass through, but not others

membrane structure

  • two layer membrane called phospholipid bilayer, composed of protien and lipids
  • lipids called phospholipids
  • contain 2 fatty acids, not 3, fatty acids are hydrophobic
  • contain phosphate groub in place of 3rd fatty acid


  • membranes not flexible, rigid
  • protiens move freely in membrane plane
  • called fluid mosaic

diffusion and osmosis

diffusion-the tendency of molecules to move from a higher concentration to a low concentration until equilibreum is reached

Passive transport

  • diffusion across a membrane
  • cell uses no energy
  • selectively permeable membrane
  • osmosis-passive transport of water across a semipermeable membrane
  • in osmosis water moves across membrane not the solute

Hyper tonic-solution with a higher concentration of solute and a lower concentration of water

hypotonic- solution wit ha lower concentration of solute and a higher water concentration

isotonic-solution with equal solute concentration

Effect on living animal cells

  • osmoregulation-control of water balance
  • animals must use this when exposed to hypertonic or hypotonic environments
  • fish use gills and kidneys to keep too much water out

Effect on living plant cells

  • most plants thrive in a hypotonic environment when there is more water
  • plants become wiltedin isotonic environment


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