MULTIPLE CHOICE

Which of the following describes the function of the endodermis?

• It controls the movement of water and ions to the xylem using a Casparian strip.

• It releases root pressure as water moves into the xylem by osmosis.

• It allows water molecules to cling to the surface by cohesion so that a continuous column is created.

• It forms a system of inter-connected plasmodesmata through which water and ions can move.

The function of the companion cell in mature phloem tissue is that it

• Provides structural support for the sieve tubes

• actively moves sucrose out of neighbouring photosynthesizing cells to the sieve tubes

• moves sucrose against a concentration gradient into the xylem

• contains a nucleus needed for cell division of the sieve tube elements

Which of the following describes the correct sequence by which water is lost through transpiration?

• Water passes from the xylem into the mesophyll cells.

• Water travels from cell to cell down a water potential gradient.

• Water evaporates from the surface of the mesophyll cells.

• Water leaves through the stomata by diffusion

Which of the following does NOT describe how mineral ions are transported from the soil to the endodermis of the root?

• Transported with water via the apoplast route.

• Carried across the root cells passively with water in the transpiration stream

• By active transport via the apoplast route

• By passive diffusion across the apoplast route

In a study of water movement in plants, the cut end of a leafy shoot is placed in a dilute solution of a dye. After a few hours, deposits of the dye accumulate in the leaves. The rate of movement of the dye up the stem is NOT increased by:

• humidity

• wind speed

• temperature

• availability of water

Which of the following causes the stomata to open?

• an increase in carbon dioxide in the airspaces in the leaves

• a decrease in the turgor pressure in guard cells

• accumulation of water in guard cells by active transport

• an influx of K+ into guard cells followed by water by osmosis

State TWO roles of xylem vessels and comment on the importance of the wall thickenings in relation to the stated roles.

which of the following is a correct definition of the term habitat?

• The relationship between an organism and other species
• The interacting community of organisms and the environment
• the way in which the environment is exploited by the organism
• A location within a biome where an organism dwells

Net primary production (NPP) is

• the transfer of energy through an ecosystem
• the amount of organic material available to herbivores
• the amount of organic material made in photosynthesis
• Option 4
• the amount of energy reaching the earth's surface

The figure below represents an ecological pyramid of numbers. The species of organisms in the pyramid are blackbirds, aphids, lice and cherry trees. match EACH of the species below with the options above.

• A
• B
• C
• D