Solutions10
Your laboratory partner has an open beaker of pure water. By definition, the water potential of
this water is - ANSWERS -E. zero
If P=.3 MPa and S=-.45 MPa, the resulting psi is - ANSWERS -C. -.15 MPa
The value for psi in root tissue was found to be -.15 MPa. If you take the root tissue and place it
in a .1 M solution of sucrose (psi = -.23), net water flow would - ANSWERS -C. be from the tissue
into the sucrose solution
A plant cell with a solute potential of -.65 MPa maintains a constant volume when bathed in a
solution that has a solute potential of -.3 MPa and is in an open container. What do we know
about the cell? - ANSWERS -E. The cell has a pressure potential of +.35 MPa
1. Why is it important that an experiment include a control group? - ANSWERS -C. Without a
control group, there is no basis for knowing if a particular result is due to the variable being
tested or to some other factor
2. Water is able to form hydrogen bonds because - ANSWERS -E. The water molecule is polar
3. What determines the cohesiveness of water molecules? - ANSWERS -C. Hydrogen Bonds
4. Which of the following is possible due to the surface tension of water? - ANSWERS -A. A
water-strider can walk across a small pond
, 5. Hydrophobic substances like vegetable oil are - ANSWERS -A. non-ionic or non-polar
substances that repel water
6. The molecular weigh of glucose (C6H12O6) is 180 g. To make a .5 M solution of glucose, you
should - ANSWERS -D. Dissolve 90 g of glucose in a small volume of water , and then add more
water until the total volume of the solution is 1 L.
7. What would be the pH of a solution with a hydrogen ion concentration (H+) of 10^-8 M? -
ANSWERS -A. pH 8
8. Which of the following solutions has the greatest concentration of hydrogen ions (H+)? -
ANSWERS -E. Gastric Juice at pH 2
9. Which of the following statements is true about buffer solutions? They - ANSWERS -B. tend to
maintain a relatively constant pH.
10. One of the buffers that contribute to pH stability in human blood is carbonic acid (H2CO3).
Carbon acid is a weak acid that dissociates into a bicarbonate ion (HCO3-) and a hydrogen ion
(H+).
Thus, H2CO3 --> HCO3- + H+
If the pH of the blood drops, one would expect - ANSWERS -C. the HCO3- to act as a base and
remove excess H+ with the formation of H2CO3.
11. Which of the following is an example of a hydrophobic material? - ANSWERS -A. wax
12. Which property of the carbon atom gives it compatibility with a greater number of different
elements than any other type of atom? - ANSWERS -B. Carbon has a valence of 4
13.The two molecules shown in Figure 4.1 are best described as (glucose and fructose) -
ANSWERS -E. Structural Isomers