BIOL 1260 Exam II

the functions of the _____ system include taking in water and ions from the soil, anchoring the plant, and storing molecules

• shoot

• root

• photosynthetic

• vascular

stomata and epidermal cells are in the ______ system of a plant

• dermal

• ground

• vascular

• epidermal

Which of the following statements about stomata are TRUE?

• stomata are critical for the process of transpiration

• stomata open when CO2 is necessary for photosynthesis

• all of these are true

• stomata are part of the dermal tissue system

what are the two conductive cells in the xylem?

• tracheids and vessel elements

• parenchyma and collenchyma

• vessel elements and sieve tube elements

• tracheids and companion cells

what drives the bulk flow of water through the xylem?

• active transport by sieve tube elements, generating positive pressure

• the number of companion cells in the phloem, which connects to the xylem

• evaporation of water from the leaves, generating negative pressure

• active transport by tracheids and vessel elements, which uses ATP

the ________ pathway (for how water travels into plants from soil) is blocked by the Casparian strip

• symplastic

• apoplastic

• transmembrane

• none of these

water moves from an area of ____ water potential to an area of ____ water potential

• high; low

• low; high

• negative; positive

water potential in a cell is lowered by ....

• the addition of water

• an increase in temperature

• the addition of solutes

• a decrease in solutes

Answer explanation

solute potential is ALWAYS negative if there are solutes in the solution! the more solutes, the more negative the solute potential, which drives down the water potential

If a plant cell is placed into distilled water, water will enter the cell. As a result of this water movement into the cell…

• the cell's water potential and pressure potential will decrease

• the cell's water potential will increase, the pressure potential will decrease

• the cell's water potential and pressure potential will increase

• the cell's water potential will decrease, the pressure potential will increase

Answer explanation

Pressure potential increases because the water exerts positive pressure on the inside of the cell walls - turgor pressure! 

Water potential will also increase, as the pressure potential increases!

in plants, a source has a ____ concentration of sugar and a sink has a ____ concentration of sugar

• high; high

• high; low

• low; high

• low; low