THE SEMIPERMEABLE MEMBRANE:PHOSPHOLIPID BILAYER

Monday November 22, 2010

IN YOUR NOTEBOOKTerm Definition Polar or

Non-PolarExample

Hydrophobic

Hydrophilic

Remember: Water is a polar molecule.

Like Attracts Like

WARMUP

Pass in Lab ReportsWatch the demonstration.

1. Explain how water is interacting with the magic sand and clear spheres.

2. What does this tell you about the properties of these substances.

THE PHOSPHOLIPID BILAYER

IN YOUR NOTES, SKETCH AND LABEL A SINGLE PHOSPHOLIPID.

HEADS AND TAILS OF THE PHOSPHOLIPID BILAYER

http://telstar.ote.cmu.edu/biology/MembranePage/index2.html

Passive Transport Does Not Require ENERGY… Substances flow down the Concentration Gradient.

We’ve seen:

WaterGlucoseIodine

ACTIVE TRANSPORT REQUIRES ENERGY TO MOVE MOLECULES ACROSS THE MEMBRANE

NOW: LET’S MODEL THE PHOSPHOLIPID BILAYER

Follow the directions on your worksheet.

Answer all questions.

Work in pairs; Each person must complete his/her own worksheet.

QUIZ FEEDBACK

75% H20

25% NaCl

40% H20 60% NaCl

Question #1:Some common misunderstandings- NaCl can pass through membraneNaCl soaks up the waterThe cell will actually swellHypotonic Solution

Question #2:Looking for a basic definition of selective permeability and an example…What were some examples in class??

#3: Think back to question #1, and the elodea lab

#4: Proteins can’t get re-absorbed (why?).Glucose is mostly re-absorbed (why?)

HOMEWORK

Read BSCS Membranes Essay p. 220-221.

Complete reading guide questions in Notebook.