Chapter 43 Masteringbiology

How does carbon dioxide enter a leaf?
– CO2 is moved by active transport into the leaf by special cells called guard cells.
– CO2 passes through openings called stomata on the leaf surface.
– CO2 diffuses through the epidermal cells into the mesophyll.
– CO2 travels dissolved in the water in the xylem.
– Atmospheric pressure forces CO2 through pits on the leaf surface.

CO2 passes through openings called stomata on the leaf surface.

Secondary growth NEVER occurs in _____.
– leaves
– stems and leaves
– roots
– stems
– roots and leaves

leaves Secondary growth never occurs in leaves.

____ provides cells for secondary growth.
– Vascular cambium
– Secondary phloem
– Secondary xylem
– Apical meristem
– The root

Vascular cambium Vascular cambium is lateral meristem that provides cells for secondary growth.

Vascular cambium forms wood toward the stem’s _____ and secondary phloem toward the stem’s _____.
– surface … center
– center … center
– surface … surface
– top … bottom
– center … surface

center … surface Wood, or secondary xylem, is formed toward the stem’s center, and secondary phloem is formed toward the stem’s surface.

What is the function of cork?
– regulating the opening and closing of stomata
– providing a site for photosynthesis
– providing cells for primary growth
– providing cells for secondary growth
– insulation and waterproofing

insulation and waterproofing Cork insulates and waterproofs roots and stems.

How is the supply of vascular cambium maintained?
– by the differentiation of apical meristem
– by the differentiation of secondary xylem
– by the division of its cells
– by the differentiation of cork
– by the differentiation of secondary phloem

by the division of its cells When a vascular cambium cell divides, one cell differentiates and the other cell remains meristematic.

In a dicot stem, the ________ is between the vascular cambium and the cork cambium.
– vascular cambium
– phloem
– vascular cylinder
– cork
– xylem

phloem

Which of these tissues is between the epidermis and the vascular bundle in a young dicot stem?
– phloem
– pith
– cortex
– ground tissue
– xylem

cortex

Which of the following makes up most of an old tree trunk?
– secondary xylem
– primary phloem
– meristem tissue
– primary xylem
– secondary phloem

secondary xylem

In leaves, chloroplasts are found in _____.
– xylem
– palisade mesophyll
– phloem
– cuticle

palisade mesophyll Both the palisade and spongy mesophyll contain chloroplasts.

Most of a carrot, a root adapted for carbohydrate storage, is:
– endodermis.
– phloem.
– xylem.
– pericycle.
– cortex.

cortex

Root hairs develop from the:
– Casparian strip.
– pericycle.
– cortex.
– endodermis.
– epidermis.

epidermis

The location of the pericyle is best described as:
– the outermost layer of the vascular cylinder.
– just beneath the epidermis.
– adjacent to the apical meristem.
– lining the cells of the endodermis.
– between layers of primary xylem and primary phloem.

the outermost layer of the vascular cylinder.

Under the influence of hormones, branch roots emerge from the ________ of a growing root.
– central cylinder
– endodermis
– epidermis
– Casparian strip
– pericycle

pericycle

On the tip of the root, the apical meristem forms the ________, which prevents the meristem from being worn away as it pushes through the soil.
– cortex
– root cap
– epidermis
– endodermis
– pericycle

root cap

You found the following plants growing on campus during a field trip: a small plant with a notable absence of root hairs; a short, stubby plant with an enlarged taproot; a tall annual herb with fungal strands extending from its roots; a low-growing plant with nodules on the roots; and a woody shrub with an extensive fibrous root system.

Based on this scenario, which plant is most likely a legume with nitrogen-fixing bacteria?
– the woody shrub with the fibrous root system
– the plant with the root nodules
– the plant with no root hairs
– the plant with the enlarged taproot
– the annual herb with the fungal-root association

the plant with the root nodules

The concentration of nutrients in plants is approximately the same as the concentration of nutrients in the surrounding soil.
– True
– False

False

Diffusion doesn’t require energy. Why do plants expend energy in active transport to transport minerals into root hairs?
– Minerals are strongly attracted to soil particles.
– Mineral concentrations in the soil are too high for diffusion.
– Minerals are too large for diffusion.
– Mineral concentrations in the soil are too low for diffusion.

Mineral concentrations in the soil are too low for diffusion.

All of the following are part of a plant’s shoot system EXCEPT:
– mycorrhizae.
– flowers.
– stem.
– buds.
– leaves.

mycorrhizae

What cellular feature allows a mineral such as manganese to diffuse from cell to cell after being taken up by roots?
– microfilaments
– secondary cell walls
– sieve plates
– plasmodesmata
– microtubules

plasmodesmata

Bacteria-containing nodules in the roots of legume plants aid in the utilization of:
– trace elements.
– carbon dioxide.
– nitrogen.
– water.
– phosphates.

nitrogen

Water flows upward in some xylem tubes and downward in others.
– True
– False

False

The ________ theory explains the movement of water and minerals through xylem.
– bulk-flow theory
– assisted diffusion theory
– cohesiontension theory
– translocation theory
– pressure-flow theory

cohesiontension theory

In the cohesion-tension theory, "cohesion" refers to the:
– use of water in photosynthesis, resulting in a shortage of water in the leaf.
– tendency of water molecules to be attracted to minerals in the water.
– attraction of water molecules for one another.
– evaporation of water from the stomata of the leaf.
– process of osmosis that pulls water into the root.

attraction of water molecules for one another.

When potassium ion is transported into guard cells, water:
– enters by osmosis.
– is actively transported out of the cells.
– moves to the edge of the cell.
– leaves by osmosis.
– is actively transported into the cells.

enters by osmosis.

Which of these processes is responsible for leaves being considered sugar sources?
– catabolism
– Krebs cycle
– photosynthesis
– citric acid cycle
– glycolysis

photosynthesis Leaves produce sugar via photosynthesis.

_____ transport(s) sugars from leaves to, for example, taproots.
– Blood vessels
– Tracheids
– Vessel elements
– Xylem
– Phloem

Phloem is responsible for the transport of sugars.

Sugar moves from leaves into the _____ of _____ by _____.
– sieve-tube members … xylem … active transport
– tracheids … phloem … diffusion
– tracheids … phloem … active transport
– sieve-tube members … phloem … active transport
– sieve-tube members … phloem … diffusion

sieve-tube members … phloem … active transport

The water pressure that pushes water and sugar from sugar source to sugar sink is referred to as _____.
– translocation
– transpiration
– bulk flow
– solute pressure
– root pressure

Bulk flow is the force responsible for the translocation that occurs in phloem.

Water moves into phloem by _____.
– osmosis
– endocytosis
– root pressure
– active transport
– transpiration

Water moves down its concentration gradient into phloem by osmosis.

At a sugar sink, sugar is removed from phloem by _____.
– osmosis
– root pressure
– active transport
– diffusion
– transpiration

Active transport moves sugar from phloem into a sugar sink.

In a sugar sink, such as a taproot, sugar is converted into _____.
– glycogen
– cellulose
– fatty acids
– starch
– proteins

starch

_____ is responsible for the movement of sugars from leaves to taproots; _____ is responsible for the movements of sugar from taproots to leaves.
– Bulk flow … bulk flow
– Bulk flow … root pressure
– Root pressure … bulk flow
– Bulk flow … transpiration
– Transpiration … transpiration

Bulk flow … bulk flow

Tree roots are a ________ of sugars in spring and a ________ in the fall.
– source; source
– sink; sink
– sink; source
– source; sink

source; sink