Chapter 29 - Plant Structure Flashcards
Plants have developed BOTH cuticles and crassulacean acid metabolism (CAM) in an attempt to limit which of the following?
water loss
In which direction would phloem sap flow if there were a greater concentration of sucrose molecules in the root phloem compared with the leaf phloem?
from root to leaf
Assuming the stomata are open to the same degree, the rate of transpiration should _____ on a rainy day compared with a sunny day because the H2O concentration gradient from the inside to the outside of the leaf would _____.
decline; decrease
Vascular plants hydrate photosynthetic cells using _____, whereas bryophytes do so using _____.
soil water; surface water
Land plants are descended from:
green algae.
Plants lose a great deal of water from their leaves in a process referred to as:
transpiration.
CAM photosynthesis improves the CO2/H2O exchange ratio because:
CO2 capture occurs at night when the gradient for diffusion of H2O out of the leaf is smaller.
The structure(s) that allow(s) gasses, such as CO2, to diffuse into and out of a leaf is/are the:
stomata.
Guard cells can actively increase their volume and, therefore, size by:
increasing the amount of solutes, such as K+ and Cl–.
Which of the following statements about transpiration is TRUE?
Transpiration sets in motion the movement of water from the roots to the leaves.
What happens to the tension in the xylem when the stomata close and evaporation stops?
It drops to a value closer to that of the water-filled pores in the soil.
If water molecules (H2O) suddenly stopped forming hydrogen bonds with each other, how would water transport in vascular plants change (if at all)?
It would stop, because water transport relies on H2O molecules being connected by hydrogen bonds.
Unlike xylem, phloem is made up of cells:
That are still metabolically active.
Water is transported from the soil to the leaves in the:
xylem.
Which of the following substances helps make cells of xylem rigid to avoid collapse?
lignin
Which of the following statements BEST defines cavitation?
Cavitation is the formation and expansion of gas bubbles in the xylem
Why may young leaves that are just emerging from the bud be considered “sinks” for phloem transport?
They consume more carbohydrates than they produce
Vascular plants store most carbohydrate reserves as:
starch
Which of the following are NOT a correct match of cells and their function?
parenchyma cells: transport of water
Carbohydrates are stored in the roots, but they may also be released into the surrounding soil, where they feed the microbial community
true
A companion cell supports a sieve element by performing specific cellular processes.
true
Applying fungicides to plants may result in a phosphorus deficiency. What is the MOST likely explanation for this observation?
The fungicide destroys mycorrhizal symbionts.
_____ are the structures formed by roots that house nitrogen-fixing bacteria.
Root nodules
Before the development of the Haber-Bosch process, NH3 could be produced from N2 only by:
prokaryotes
