Chapter 4 Notes 


I.                     Exchange with the Environment

cells must get energy, raw materials & get rid of waste

A.       What is Diffusion?

movement from area of high concentration to area of low concentration (from a lot to a little/balances


uses no energy

1.      Diffusion of Water

Water-necessary for life

Osmosis=movement of water from lot to little across a semipermeable (lets some things in/keeps some things out) membrane/balances/uses no energy


 2.      The Cell and Osmosis

water & salts in plasma/in red blood cells (in balance)

if red blood cells put into pure water, water would flow in and cell would burst

if red blood cell put into salt water, cell would shrivel


B.       Moving Small Particles

particles move thru channels (proteins) in cell membranes

·         passive transport-diffusion & osmosis, uses no energy(from lot to little)


·         active transport-uses energy, from little to lot



C.       Moving Large Particles

large particles move by endocytosis & exocytosis, use energy

1.       Endocytosis

active transport of large particles into the cell


2.       Exocytosis

active transport of large particles out of the cell

II Cell Energy

All cells require energy

A.      From Sun to Cell

Sun -  source of most life energy

1.        Photosysnthesis

Chlorophyll(pigment) in chloroplast catches sun’s energy

There mixes CO2 + H2O to produce food(glucose sugar)

2.        Getting Energy from Food




B.      Getting Energy from Food

Cellullar respiration-uses O2 to break down food to get energy

Fermentation-uses NO O2 to release energy

.1     Cellular Respiration

Breathe to get air for Cell. Resp.

In mitochondria, O2 mixes with sugar/glucose to release ATP(energy)






2.        Connection Between Photosynthesis and Respiration


3.       Fermentation

In animal cells IF O2 has been used up.








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