Water and the plant Flashcards by Rachel Larson

What is the main difference between plants and animals?

Plants are autotrophic and animals are chemotrophic

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What two things can plants do that animals cannot?

Plants can do photosynthesis, and can make a lot of unique secondary metabolites

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What four things do plants need? (hint: think of the phases of mater)

Water, carbon dioxide, oxygen, minerals (iron, magnesium, ect), and energy

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What are the three major tissue types of a plant and where can they be found?

Dermal: covers the surface of the plant
Ground: makes up the bulky internal part of the plant
vascular: xylem and phloem

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Where can merisomatic tissue be found?

The axillary buds (between branching points), the very top, and the very bottom

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Name all the tissues of the leaf from top to bottom.

Cuticle, epidermis, spongy mesophyll, vascular tissue surrounded by bundle sheath (parenchymal) cells, dermal tissue (with stomata), cuticle

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What type of meristematic tissue does stems have? How about roots and leaves?

Stem: apical, vascular cambium, cork cambium
Root: apical, pericycle (parenchymal cells that like just inside the endodermis), vascular cambium, cork cambium

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Match tugid, plasmolyzed, and flaccid cells with hypertonic, isotonic and hypotonic solutions

turgid: hypotonic
plasmolysis: hypertonic
flaccid: isotonic

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What is the equation for rate of diffusion (J(s))?What about time of diffusion? What is this equation called?

J(s)=-D(s)*(delta Cs/ delta X)
time = L^2/2D
Ficks law

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Is the contact angle of water on a wettable surface greater or lesser than 90 degrees?

lesser

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Is the contact angle of water on a non-wettable surface greater or lesser than 90 degrees?

greater

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What’s the equation of rise within a capillary tube?

rise=15E-6[m^2]/radius

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When is entropy of water highest (solute added? no solute? saturation?)

Entropy of water is highest when no solutes are added

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What three properties does the hydrogen bonds of water cause?

High specific heat, high latent heat of vaporization, and high surface tension

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What is the difference between specific heat, and latent heat of vaporization

specific heat: amount of heat required to raise the temp 1 K
latent heat of vaporization: the amount of energy needed to move molecules from the liquid to gas phase

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What are the units of surface tension?

units: J/m^2 or N/m or pascals

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what is the difference between cohesion and adhesion?

Cohesion: mutual attraction between molecules
Adhesion: attraction of water to a solid surface

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What are two differences between the water level (meniscus) in a wettable surface versus a non-wettable surface?

Wettable surface: water line is above the water level and is concave down
non-wettable surface: water line is below the water level and is concave up

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What is the formula for capillary rise?

Rise [m] = 14.9E-6/radius

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What is diffusion proportional to? What is the formula? What are the units?

Proporional to the position-dependent concentration gradient of the solute (c(s))
J(s)=-D(deltaC/deltax)
all of this is in terms of the solute
Units: moles/m^2s

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What is the diffusion constant dependent on?

The size of the molecule, the medium its in, and the temperture

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What is the formula for time taken to diffuse across distance L?

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t = L^2/2D

What is the mathematical definition of chemical water potential?

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Chemical potential of x is the derivative of Gibbs free energy as the concentration of chemical x changes

What is the formula for the mole fraction of water in a system?

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Nw=nw/(nw+ns)

What is the equation for the chemical potential?

u= u* + RTlnN + VP + mgh

What is the equation of chemical potential per unit volume? What are the units

psi = psi(s) + psi(p) + psi(g) = -RTΣCs + psi (p) +rho*g*h ΣCs = concentration of total solutes (osmolarity) units = J/m^3 = N/m^2

What is osmolarity?

the sum of all solute concentrations in a solution.

What is the pressure potental of pure water at 1 atm?

psi (p) at standard conditions of pure water is 0

what is the units for specific heat?

energy/g*C

Where do plants have the most negative water potential? why?

Plants have the most negative water potential at the leaves internal air space. This is due to the evaporation of water into the surrounding, much more negative, air

What is the difference between a tracheid, vessel element, and xylem?

Tracheid: Present in all vascular plants (gymnosperms). Contains no perforated end-plants, but does contain complex pit membranes Vessel elements: present only in angiosperms and contains perforated end plates and simple pit membranes. Shorter and wider than tracheid xylem: appears in all higher order plants

What has lower water potential: sandy or clay soil?

Sandy dry soil

What protein stops water loss at mature root tissue?

Suberin

What three ways does water go through the plant into the xylem?

apoplast: Water moves along the outside of the cell membrane symplast: water moves within the cells and plasmodesmata transverse: water crosses multiple cell membranes

What is the casparian strip? What does it do?

The Casparian strip blocks water from entering the xylem any way but the symplastic pathway

What is the pressure potential of wet soil? What is the pressure potential of water under a curved surface?

Pressure potential of wet soil is 0. Pressure potential under a curved surface develops a negative potential -2T/r. As soil tries, smaller and smaller pores make the potential go negative

What are the elements in plant cell walls (4)?

Cellulose, hemicellulose, pectin, and proteins

Are aquaporons passive, active, or secondarily active

Passive

What is the driving force of water through the xylem?

Pressure potential

What factors modulate xylem water conductance (4)?

Distribution of diameters, lengths, vessel number, and the resistance between them

What are the three major causes of embolism?

1) Drought 2) freezing 3) Low pressure cavitation

What force gets water up the plant?

Cohesion-tension of the sap ascent

What generates the force that causes water to move up the tree?

Transpiration at the leaves

Why does the water not boil in the low pressure of the xylem?

1) Cohesion and adhesion raises the free energy needed to vaporize water 2)Xylem is structed to minimize nucleation sites

Where does evaporation of water occur?

At the leaf interface

What is the equation that relates water potential to activity?

psi=RT(Ln(activity))/V

What is the formula for activity of water?

activity=%RH/100%

What is the equation of transpiration rate?

J=flow rate= kRT(delta C)/r r= resistance delta c= concentration of water in the leaf - concentration of water in the air

What is holding capacity of air (for water) dependent on?

Temperture

What are the two sources of resistance when it comes to evaporation at the leaves? what are they controled by?

stomatal resistance: correlated to if stomata is open or closed boundary resistance: correlated to air movement (wind). Which creates a thinner boundary layer

What are the two types of guard cells and what are their differences?

1) grasses: dumbbell-shapped and flanked by subsidiary cells that both participating in openings 2) everyone else: kidney shapped, with optional subsidiary cells

Why is the ratio of CO2 gained to H2O lost so high?

1) The concentration gradient between water and air is 50x higher than that of CO2 and the leaf 2) CO2 is much bigger and so diffuses slower 3) CO2 must cross three plasma membranes in order to be fixed

What is incipient plasmolysis? When does it occur and what is the water potential at the point?

Incipient plasmolysis is when the cell's pressure potential goes to 0. When this happens the chemcial potential is the water potential of the cell.

Water and the plant Flashcards

(53 cards)