Cell TransportCell Transportchap. 7-3chap. 7-3

https://www.pinterest.com/pin/225039312606126463/

I. Cell MembraneI. Cell Membrane1) POLAR ends face INSIDE & OUTSIDE cell [where water is]

2) NONPOLAR tails face each other inside bilayer [to avoid water]

Outsideof cell

Insideof cell(cytoplasm)

Cellmembrane

Proteins

Proteinchannel

Lipid bilayer

Carbohydratechains

http://www.bioteach.ubc.ca/Bio-industry/Inex/

3) FUNCTION: SELECTIVE PERMEABILITY = allows only certain materials to go into & out of cell

a. Why doesn’t the cell membrane let everything through?

HOMEOSTASIS!- Cells maintain a stable environment by controlling what enters & leaves.

II. Cellular Transport – Two II. Cellular Transport – Two Major Types (Passive & Major Types (Passive & Active Transport)Active Transport)1.Passive Transport = moves molecules across cell mem. using NO ENERGY

Movement going with the concentration gradient (normal flow)

1.Diffusion – molecules move from HIGH conc. to LOW conc.

a. Small molecules: O2, CO2

b. Slow process

A. Types of Passive Transport

Passive Transport Video Cliphttps://www.pinterest.com/pin/

225039312606104881/

PROBLEM for PROBLEM for Cells?Cells?

Cell Cell membranes membranes areareSELECTIVELY SELECTIVELY PERMEABLEPERMEABLE

2. Facilitated Diffusion – movement of molecules with help of a carrier protein

a.Moves large molecules

like Glucose and Fructose (C6H12O6)

b. Faster than diffusion

http://www.sirinet.net/~jgjohnso/homeostasis.html

3. Osmosis – diffusion of WATER across cell membrane

* H2O moves to area with LESS WATER

a. Direction of Osmosis:1) Hypotonic Solution = H2O moves INTO cell & CELL EXPANDS

2) Hypertonic Solution = H2O moves OUT OF cell & CELL SHRINKS

3) Isotonic Solution = H2O moves INTO & OUT OF cell & cell stays NORMAL SIZE

* EQUILIBRIUM = concentration of molecules is same everywhere

* Molecules never stop moving – even at equilibrium

2. 2nd Type of Transport Active Transport

1. moves molecules across cell membrane using ENERGY

B. Types of Active Transport

1. Transport Proteins: in membrane- move substances from low to high conc. (opposite of how it wants to move)

2. Endocytosis = cell surrounds & ingests materials from OUTSIDE to INSIDE cell using VESICLES

http://www.sirinet.net/~jgjohnso/homeostasis.html

a. Steps:1) membrane folds in & forms pocket2) Pocket closes & pinches off in cell vesicle 3) vesicle fuses w/ organelles to release contents

b. Two Types of Endocytosis:1)Phagocytosis – LARGE particles (food) or whole CELLS (bacteria) into cell

2) Pinocytosis – large amounts of liquids/ fluids into cell

3. Exocytosis –releases large amounts of material to the OUTSIDE of the cell using VESICLES

a. Steps:1)Vesicle forms, travels to & fuses w/ cell mem.

2)Vesicle opens to outside & releases contents

http://www.sirinet.net/~jgjohnso/homeostasis.html

Video clip