Bellwork Wednesday 11/9*tutorial today for missing work & test makeup

1. What is a phospholipid?2. How do cell membranes form on their own

Agenda:

1. Finish Notes

2. Q & A worksheet

3. Posters!

• Forms a barrier around all cells

• Are made mostly from fats– They don’t dissolve in water– Are special fats called Phospholipids

Cell Membrane

- Phospholipids in the cell membrane Form a Lipid Bilayer

- 2 layers back-to-back

• Lipid Bilayer is flexible (or fluid)

• Cholesterol embedded in membrane– Cholesterol adjusts fluidity– More cholesterol makes membrane stiffer– Less cholesterol makes membrane more liquidy

• Transport Proteins– Are like a pore or channel in membrane– Move nutrients in or waste out

Transport Protein

– 100’s of different kinds• Each nutrient needs it’s own• Shape of each Transport Protein fits its nutrient

More Transport Proteins

• Fluid Mosaic Model– fluid

• lipid bilayer is flexible

– Mosaic • Many Transport Proteins embedded in membrane• Looks like a mosaic, sorta

• Selective Permeability– Some molecules can pass through

• Like nutrients with Transport Proteins

– Some molecules can’t pass through• Like many toxins that don’t have Transport Proteins

Cell Membrane Poster20 points, work in pairs

Include and LABEL:– Phospholipid

• Polar Head• Non-polar Tail

– Lipid Bilayer– Transport Proteins– Cholesterol

Explain IYOW: (use the question in your answer)

1. Why polar heads face out2. Why nonpolar tails are inside3. What transport proteins do4. What cholesterol does

Use at least one 3D item

Please:Only take a few materialsReturn everything you don’t useDon’t throw thingsClean your workspace