plant structure and function

A scientist genetically modifies a plant to lack phloem tissue. What will be the most immediate effect on the plant?

• A) The plant will be unable to transport water to its leaves
• B) The plant will not be able to photosynthesize
• C) The plant will be unable to transport sugars to non-photosynthetic tissues
• D) The plant will wilt immediately due to lack of water

A farmer grafts a cutting from a high-yield fruit tree onto the rootstock of a hardy but low-yield tree. What is the expected benefit?

• A) The tree will produce seeds instead of fruit
• B) The tree will produce more leaves but fewer fruits
• C) The tree will have the hardiness of the rootstock and the fruit production of the grafted plant
• D) The tree will become sterile

A time course is developed to follow the fate of the vascular bundles in the stem of dicots. Sections along the stem are fixed, stained, and observed under a microscope. What happens to the vascular bundles in the stem of a dicot as the plant matures?

• a. The vascular bundles join to form growth rings.
• b. The vascular bundles divide into primary xylem and primary phloem.
• c. The vascular bundles divide into secondary xylem and secondery phloem.
• d. The vascular bundles die out.

Stomata close in response to bacterial infection. This response is a defense mechanism because it ________ .

• a. restricts the entry of O2
• b. restricts the entry of CO2
• c. prevents further entry of pathogens
• d. prevents further entry of pathogens

The process of bulk flow transports fluids in a plant. What are the two main bulk flow processes?

• a. Movement of water up the xylem and movement of solutes up and down the phloem
• b. Movement of water up the phloem and movement of solutes up and down the xylem.
• c. Movement of water up and down the xylem and movement of solutes up the phloem
• d. Movement of solutes up the xylem and movement of water up and down the phloem

What is the advantage of a root cap covering the apical meristem of a root?

• a. It provides protection and helps in absorption.
• b. It increases the surface area of root for absorption of water and minerals.
• c. It protects meristem against injury and provides lubrication for the growing root to dig through soil.
• d. It protects the meristem against injury and helps in absorption.

A pulse of sugars labelled with a fluorescent dye is supplied to leaves of young plants. After a brief interval, tissue sections are obtained from the plant and examined under the fluorescence microscope. Tissues are scored for the presence of fluorescence and ranked from very high to low fluorescence. Which cells would contain the most fluorescence?

• a. xylem
• b. companion cells
• c. sieve elements
• d. epidermis

Samples of leaves from monocots and dicots are piled on the table in a laboratory and students are sorting the leaves. What information will help them know which leaves to identify as monocots?

• a. Bulliform cells are usually absent from monocots whereas they are present on the upper epidermis of dicot leaves.
• b. Monocots have leaves with parallel venation and dicot leaves have reticulate, net-like venation.
• c. Dorsiventral symmetry is observed in monocot leaves whereas isobilateral symmetry is observed in dicot leaves.
• d. Monocots have leaves with reticulate, net-like venation and dicot leaves have parallel venation.

Plants regulate their internal water potential by opening and closing stomata. Which events take place when stomata open?

• a. Water vapor is lost to the external environment, increasing the rate of transpiration.
• b. Water vapor is lost to the external environment, decreasing the rate of transpiration.
• c. Water vapor enters the spaces in the mesophyll, increasing the rate of transpiration.
• d. The rate of photosynthesis drops when stomata open.

If the concentration of solute increases in a cell, the water potential will ________ inside the cell and water will move ________ the cell.

• a. increase; out of
• b. increase; into
• c. decrease; into
• d. decrease; out of