AP Biology – Chapter 3 Water (Worksheet)
Lookabaugh – Campbell Seventh Edition
Objectives:
 Know the importance of hydrogen bonding to the properties of water
 Four unique properties of water and how they contribute to life on Earth
 Know how to interpret the pH scale
 Know the importance of buffers in biological systems
Concept: The polarity of water molecules result in hydrogen bonding
1. The structure of water is key to its special properties. Water is made up of _____
atom of oxygen and ________ atoms of __________________.
2. Water molecules are _____________ which gives the end bearing the oxygen atom a
Slightly _________ charge and the hydrogen atoms are slightly ___________ in charge.
3. ________________ bonds form between water molecules.
4. Each water molecule can form a maximum of ________ hydrogen bonds at one time.
Concept: Four emergent properties of water contribute to Earth’s fitness for life
5. Water is so unique because of its hydrogen bonds:
 ___________________ is the linking of like molecules. Think of this
property as a “water strider” walking on the top of a pond due to the
____________ tension created by hydrogen bonding between water molecules.
 __________________ is the clinging of one substance to another. Think of
water adhering to another substance like the sides of a glass or a windshield.
 __________________ is the movement of water molecules up a very thin
tube called stomata and their evaporation from the stomates in plants. The water
molecules to each other by _______________ and the walls of the xylem by
_________________.
6. Moderation of _______________________ is possible because of a water’s high
specific heat.
 Specific heat is the amount of heat required to __________________ or
lower the temperature of a substance _______ degree Celsius. Rleative to most
other materials, the temperature of water changes less when a given amount of
heat is lost or ___________________. The high specific heat of water makes the
Earth’s oceans relatively _________________ and able to support _________
quantities of life.
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7. ___________________ of bodies of water by floating ice.
 Water is less ____________ as a solid than a liquid which is opposite of most
other substances. Since ice is less ____________ it will float. This keeps large
bodies of water from __________________ and moderates the
_______________.
8. Water is an important ____________________. (A substance something dissolves in.)
 ______________ substances are water-soluble. These include IONIC
compounds, ____________ molecules like sugar and some proteins.
 ________________ substances like oils are nonpolar and will not
_______________ in water.
***This is an important concept to understand when studying the cell membrane, its
structure and how things are allowed passage in and out of the cell.
Concept: Acidic and basic conditions affect living organisms
9. The pH scale runs between _______ and __________ and measures the relative
____________ and ____________ of aqueous solutions. Draw the scale below and list
and example at each increase of 10 fold.
10. Acids have an excess of ________ ions and a pH below _________.
11. ____________ have and excess of _________ ions and a pH above __________.
12. Pure water is _______________ which means has a pH of _________.
13. Buffers are substances that minimize changes in the ______. The accept _______
from solution when they are in excess and donate _________ when they are depleted.
14. Carbonic acid (___________) is an important buffer in living systems. It moderates
pH changes in _________ plasma and the _____________.
AP Biology – Chapter 4 Carbon (Worksheet)
Lookabaugh – Campbell Seventh Edition
Objectives:
 Know the properties of carbon that make it so IMPORTANT.
Concept: Carbon Atoms can form diverse molecules by bonding to four other
atoms.
1. Carbon is unparalleled in its ability to form molecules that are large, complex and
diverse. Why?
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It has _______ valence electrons.
It can form up to ______ covalent bonds.
These can be _________, __________ or __________ bonds.
It can form _________________ molecules.
These molecules can be ____________, ring-shaped or _____________.
2. ___________________ are molecules that have the same molecular formula but differ
in their arrangement of these atoms. These differences can result in molecules that are
VERY different in their biological activities. Name one of these molecules:
________________
Concept: Characteristic chemical groups help control how biological molecules
function.
3. ____________________ groups are attached to the carbon skeletons give the
molecule its diverse properties. The BEHAVIOR of organic molecules is dependent of
the __________________ of their _________________ groups.
4. Some common functional groups are:
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_________________, OH These are: _______________ like ethanol, and help to
dissolve molecules such as sugar. (Think of brewing beer, yeast and sugar)
_________________, COOH __________________ acids like fatty acids and
sugars have acidic properties because it tends to ionize. Good sources for H+ ions
_________________, <CO These are found in _______________ and aldehydes
like some sugars
_________________, NH2 Amines contain this group like _________ _______
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_________________, PO3 Organic _____________ including ATP, _________
and phospholipids contain this group
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__________________, SH This group is found in some ________________
acids and forms ______________________ bridges in proteins which help with
their structure.
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