Roles of Water in Plant Physiology

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What percentage of water absorbed by the roots is lost as water vapor from the leaf during transpiration?

75%

90%

97% (correct)

50%

What is the primary function of water in maintaining cell shape and rigidity?

Regulating temperature homeostasis

Providing structural support through turgor pressure (correct)

Facilitating nutrient transport within the cell

Maintaining cell membrane integrity

What is the approximate number of water molecules diffused out for every CO2 molecule diffused in during transpiration?

200

500

300

400 (correct)

What is the molecular structure of water?

H2O Signup and view all the answers

What gives water its polarity?

The unequal sharing of electrons between oxygen and hydrogen atoms Signup and view all the answers

What is the role of water in facilitating aerobic respiration?

It is the source of O2 for energy production Signup and view all the answers

What is the main reason for the inward force at the surface of water?

The absence of water molecules above them Signup and view all the answers

What allows some objects to float or rest on the surface of water?

The surface tension of water Signup and view all the answers

What is the main reason for water's high specific heat capacity?

The disruption of hydrogen bonds before the water molecules can begin moving faster Signup and view all the answers

What helps moderate temperature fluctuations in plants?

The high specific heat capacity of water Signup and view all the answers

What is a result of water's high heat of vaporization?

It requires a high amount of heat energy to evaporate Signup and view all the answers

What is the role of hydrogen bonds in water's heat of vaporization?

They increase the heat energy required to evaporate Signup and view all the answers

What happens to the molecules with the greatest kinetic energy during evaporation of water from the leaves of a plant?

They are the most likely to leave as gas Signup and view all the answers

What is the ability of water to dissolve a wide range of substances due to?

Its polarity and ability to form hydrogen bonds Signup and view all the answers

What is the term used to describe non-polar molecules that do not interact favorably with water?

Hydrophobic Signup and view all the answers

What type of molecules tend to repel water?

Hydrophobic substances Signup and view all the answers

What is the term used to describe polar molecules that have an affinity for water and interact easily with it?

Hydrophilic Signup and view all the answers

Which of the following substances is NOT an example of a hydrophobic substance?

Sugars Signup and view all the answers

What is the primary criterion for a semi-permeable membrane to allow or block substances?

Size and charge Signup and view all the answers

In which direction do water molecules move during osmosis?

From an area of lower solute concentration to an area of higher solute concentration Signup and view all the answers

What is the result of equilibrium in the context of diffusion?

No net movement of molecules, with concentrations remaining the same Signup and view all the answers

What is the effect of higher temperatures on the rate of diffusion?

It increases the rate of diffusion Signup and view all the answers

What is the primary difference between osmosis and diffusion?

The type of particles involved Signup and view all the answers

What is the definition of diffusion?

The spontaneous movement of substances from an area of higher concentration to an area of lower concentration Signup and view all the answers

What is the effect of solute concentration on water potential?

It decreases the water potential, making it more negative. Signup and view all the answers

What is the unit of measurement for water potential?

Megapascals (MPa) Signup and view all the answers

What is the effect of pressure on water potential?

It can have either a positive or negative influence on water potential. Signup and view all the answers

What is the value of ψS for pure water?

0 MPa Signup and view all the answers

What happens to the water molecules when solutes are added to a solution?

They bind to solutes, reducing the capacity of the water to move and do work. Signup and view all the answers

What is the overall effect of adding solutes to a solution on its water potential?

It makes the water potential more negative. Signup and view all the answers