AP Biology Practice Worksheet, Water and Life
Name: Answer Key
Learning Objective 4.9: The student is able to predict the effects of a change in a component(s) of a
biological system on the functionality of an organism(s).
Instructions: Complete all empty boxes.
1. pH Practice
[H+]
10-3
[10-8]
10-7
10-1
[OH-]
pH
[10-11]
10-6
[10-7]
10-13
3
8
7
1
Acidic, Basic, or
Neutral
Acid
Base
Neutral
Acid
2. Properties of water
Property
Cohesion
Adhesion
Explanation
Hydrogen bonds hold
water molecules together
and adhere them to
hydrophilic surface
High specific heat
Heat is absorbed or
released when H bonds
break
Benefit to life
Water column is pulled up through
plant vessels (xylem)
Photosynthesis
Transpiration
Blood plasma
Temperature changes in environment and
organisms are moderated
Homeostasis
High heat of
vaporization
Hydrogen bonds must be
broken for water to
evaporate
Solar heat is dissipated from tropical
seas
Evaporative cooling
Water molecules with
high kinetic energy
evaporate; remaining
molecules are cooler
Cools surfaces of plants and animals
Less dense as a solid
H bonds in ice are
farther apart than in a
liquid
Floating ice insulates bodies of water
for life below
Universal solvent
Polar water molecules
surround and dissolve
polar solutes
Most chemical reactions in life involve
solutes dissolved in water
Buffers in cells
Acid/Base reactions
Homeostasis
1
3. Biology of Water
Phenomenon
Hydrangeas can be pink, blue, or white
depending on the pH of the soil.
Water move up xylem in a tall tree
Property
Universal solvent
A runner sweats during a run
Acid precipitation formed
Water strider walk on water
Buffers help maintain homeostasis in blood
During the winter, air temperatures in the
northern United States can remain below 0
for months; however, the fish and other
animals living in the lakes survive
Transport of nutrients and waste products in
organisms
Participate in dehydration and hydrolysis of
macromolecules
Drainage of tears from the eye
Evaporative Cooling
Universal solvent
Cohesion, specifically Capillary Action
Universal solvent
Less dense as a solid
Cohesion, Adhesion
High Specific Heat
Universal solvent
Polarity (general)
Cohesion, specifically Capillary Action
4. Molar solutions
Compound in
solution
Molecular
Formula
Glucose
C6H12O6
Lactic acid
C3H6O3
Salt
NaCl
Urea
CO(NH2)2
Sodium
hydroxide
NaOH
Elements and
mass of 1M
(grams)
C-12 (6) = 72
H- 1 (12)= 12
O-16 (6)=96
C-12 (3) = 36
H- 1 (6)= 6
O-16 (3)=48
Na=23
Cl=35
C-12 (1) = 12
H-1 (4)= 4
O-16 (1)=16
N-14 (2)=28
Na=23
O-16 (1)=16
H-1(1)=1
Molecules 1L,
1M solution
Mass of .5M
6.02 x 1023
180/2=90g/L
180 g/L
6.02 x 1023
90/2=45g/L
90 g/L
6.02 x 1023
58/2=29g/L
58 g/L
6.02 x 1023
60/2=30g/L
60 g/L
6.02 x 1023
40/2=20g/L
40 g/L
2