Life: The Science of Biology

David E. Sadava, David M. Hilliss, H. Craig Heller,May Berenbaum

Chapter 35

Transport in Plants - all with Video Answers

Educators

Chapter Questions

Problem 1

Osmosis
a. requires ATP.
$b .$ results in the bursting of plant cells placed in pure water.
$c .$ can cause a cell to become turgid.
$d$. is independent of solute concentrations.
$e .$ continues until the pressure potential equals the water potential.

Alexander Cheng

Alexander Cheng

Numerade Educator

Problem 2

Water potential
$a .$ is the difference between the solute potential and the pressure potential.
$b$, is analogous to the air pressure in an automobile tire.
$c .$ is the movement of water through a membrane.
$d$. determines the direction of water movement between cells.
$e .$ is defined as 1.0 MPa for pure water under no applied pressure.

Emily Marty

Numerade Educator

Problem 3

Which statement about aquaporins is not true?
a. They are membrane transport proteins.
b. Water movement through aquaporins is always active.
$c .$ The permeability of some aquaporins is subject to regulation.
d. They vary in abundance depending on environmental conditions.
$e .$ They enable water to pass through the phospholipid bilayer without encountering a hydrophobic environment.

Caroline Jones

Numerade Educator

Problem 4

Which statement about proton pumping across the plasma membrane of plants is not true?
a. It requires ATP.
$b$. The region inside the membrane becomes positively charged with respect to the region outside.
$c .$ It enhances the movement of $\mathrm{K}^{+}$ ions into the cell.
d. It pushes protons out of the cell against a proton concentration gradient.
$e .$ It can drive the secondary active transport of negatively charged ions.

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 5

Which statement is not true?
a. The symplast consists of the interconnected cytoplasm of living cells.
b. Water can enter the stele without entering the symplast.
$c .$ The Casparian strips prevent water from moving between endodermal cells.
d. The endodermis is a cell layer in the cortex.
e. Water can move freely in the apoplast without entering cells.

Emily Marty

Numerade Educator

Problem 6

In the xylem,
$a$. the products of photosynthesis travel down the stem.
$b$. living, pumping cells push the sap upward.
$c$. the driving force is in the roots.
$d .$ the sap is often under tension.
$e .$ the sap must pass through sieve plates.

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 7

Which of the following is not part of the transpiration-cohesion-tension mechanism?
a. Water evaporates from the walls of mesophyll cells.
b. Removal of water from the xylem exerts a pull on the water column.
$c .$ Water is remarkably cohesive.
$d .$ The wider the tube, the greater the tension its water column can withstand.
e. At each step, water moves to a region with a more strongly negative water potential.

Jennifer Hudspeth

Jennifer Hudspeth

Numerade Educator

Problem 8

Stomata
$a$. control the opening of guard cells.
b. release less water to the environment than do other parts of the epidermis.
c. open when $\mathrm{CO}_{2}$ levels inside the leaf are high.
$d$. do not respond to light.
$e .$ close when water is being lost at too great a rate.

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 9

Which statement about phloem transport is not true?
$a$. It takes place in sieve tubes.
$b$. It depends on mechanisms for loading solutes into the phloem at sources.
$c .$ It stops if the phloem is killed by heat.
d. A high pressure potential is maintained in the sieve tubes.
$e .$ At sinks, solutes are actively transported into sieve tube elements.

Jade Schlamb

Numerade Educator

Problem 10

The fibrous protein in sieve tube elements
a. may plug leaks when a plant is damaged.
b. clogs the sieve plates at all times.
$c .$ never clogs the sieve plates.
d. serves no known function.
e. provides the driving force for transport in the phloem.

Christina Sorrentino

Christina Sorrentino

Numerade Educator