overview: the molecule that supports all of life all living organisms require water more than any...
TRANSCRIPT
![Page 1: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/1.jpg)
Overview: The Molecule That Supports All of Life
• All living organisms require water more than any other substance
• Most cells are surrounded by water, and cells themselves are about 70–95% water
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
![Page 2: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/2.jpg)
The polarity of water molecules results in hydrogen bonding
• The water molecule is a polar molecule: The opposite ends have opposite charges
• Polarity allows water molecules to form hydrogen bonds with each other
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
–H
+
H
O—
—
——
+
–
![Page 3: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/3.jpg)
Hydrogenbond
–H
+
H
O
——
——
+ +
+
–
–
–
![Page 4: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/4.jpg)
Hydrogenbond
–H
+
H
O
——
——
+ +
+
–
–
–
Why Does Water Have a High Specific Heat?
![Page 5: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/5.jpg)
Evaporative Cooling
• Evaporation is transformation of a substance from liquid to gas
• Heat of vaporization is the heat a liquid must absorb for 1 g to be converted to gas
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
![Page 6: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/6.jpg)
Evaporative Cooling
• As a liquid evaporates, its remaining surface cools, a process called evaporative cooling
• Evaporative cooling of water helps stabilize temperatures in organisms and bodies of water
![Page 7: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/7.jpg)
Fig. 3-6
Hydrogenbond
Liquid waterHydrogen bonds break and re-form
IceHydrogen bonds are stable
Ice floats in liquid water because hydrogen bonds in ice are more “ordered,” making ice less dense
Q. Why Does ice Float?
![Page 8: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/8.jpg)
Hydrophilic and Hydrophobic Substances
• A hydrophilic substance is one that has an affinity for water
• A hydrophobic substance is one that does not have an affinity for water
• Oil molecules are hydrophobic because they have relatively nonpolar bonds
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
![Page 9: Overview: The Molecule That Supports All of Life All living organisms require water more than any other substance Most cells are surrounded by water, and](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56649f285503460f94c40482/html5/thumbnails/9.jpg)
Which of these substances is (are) hydophilic?Which of these substances is (are) hydophobic?