AP Bio-Water Potential & Plants

Where is CO₂ mainly needed and taken up in a plant?

• Roots

• Stem

• Flower

• Leaf

• Root hairs

Which of the following statements is true?

• Water is transported actively against a concentration gradient.

• Water flows into the direction of the lowest water potential.

• Active transport is ATP-independent.

• Osmosis requires impermeable membranes.

Bulk transport in the phloem-

• Runs strictly from the sink to the source.

• Requires no water.

• Depends on positive pressure that builds up at the source sites.

• Is completely energy independent.

• Does not occur in the roots since this is a light dependent process.

Which of the following statements is correct for stomata opening?

• Stomata take up K⁺ into their guard cells, which attracts water to enforce their opening.

• Stomata export K⁺ from their guard cells, which causes water to diffuse out, and that is the trigger for stomata to open up.

• Na⁺ is the main ion source to control stomata opening in plants.

• Most critical is the closing of aquaporins in the cell wall of guard cells to open up stomata.

• Stomata have small muscles that contract and open up the kidney shaped guard cells.

Which of the following statements is not correct?

• Phloem is living tissue that can exchange water with xylem.

• Phloem transport organic material only to the roots (top to bottom).

• Phloem can transport organic material anywhere that it is needed.

• Phloem can be found in all leaves, the stem, and the root.

• Phloem often uses sugar to supply sinks in the plant with energy rich carbon-hydrogen material.

What are the two key tissues that allow plants to transport water or organic nutrients, respectively, over long distances?

• xylem and bundle sheath cells

• periderm and phloem

• sclerenchyma and xylem

• xylem and phloem

• collenchyma and xylem

To transport water from the root into the shoot does the water potential in the xylem need to become more positive or negative?

• Positive

• Negative

• Neither positive nor negative

The soil surrounding the roots of a plant has a water potential of -15 bars. The leaves of the plant have a water potential of -18 bars.
What will happen?

• Water will leave the plant and the plant will wilt.
• Water will move from the roots to the leaves of the plant.
• Nothing - these solutions are isotonic.
• IDK - What is a bar????

A saltwater fish is accidentally placed in a freshwater aquarium in a few short hours it sadly died. Which explains why this occurred?

• The cells of the fish body were dehydrated by the quick loss of water. 
• The cells of the fish quickly absorbed massive amounts of water and it ended up killing the fish.  
  
• The fish hated the new decor in the freshwater tank. 
• It was just its time. 

Tags

NGSS.MS-LS1-2

NGSS.MS-LS1-3

Pure water has a water potential of ___.

• 1
• 0
• -1
• 100