SAFS 421 Lecture Notes - Lecture 3: Casparian Strip, Photosynthesis, Dew Point

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blackhound251

9 Dec 2017

School

UNH

Department

Sustainable Agriculture & Food Systems

Course

SAFS 421

Professor

Andrew Ogden

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Document Summary

Water potential: ability of water to do work (dissolving substances) High water potential, max water potential of pure water is 0. As water moves up through the plant, the water potential is getting lower and lower, meaning that the value of the potential is more negative. Before uptaking minerals, plants need them to be dissolved in the soil solution. S, m, p: s (-), m (-), p(+,-) Pressure potential p which results from exertion of pressure on membranes/walls as water moves in or out; can be positive or negative. Solute potential: more salts means that there is more solute potential. Less solute (h20 will move to the higher solute concentration via diffusion) As long as there are more solutes in the root, the water will want to move into the root. Application of this concept: plants may begin to wilt and you feel as though watering will help, but no turgor pressure will be regained.

Related Questions

Question 1

Plasma membranes are selectively permeable. This means that

	A.	glucose cannot enter the cell.
	B.	the plasma membrane allows some substances to enter or leave a cell more easily than others.
	C.	plasma membranes must be very thick.

Question 2

Oxygen molecules O₂ crosse a plasma membrane by

	A.	passive transport
	B.	osmosis
	C.	active transport

Question 3

Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

		A. energy and channel proteins; against (up)
		B. transport proteins that make channels ; down
		C. energy ; down

Question 4

When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will

		A. move to the side with lower water concentration
	B.	move to the side with higher water concentration
	C.	move to the side with lower solute concentration

Question 5

Kinetic energy differs from chemical energy in that

	A.	chemical energy is a particular form of kinetic energy.
	B.	kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules.
	C.	kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement.

Question 6

When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.

	A.	exergonic; endergonic
	B.	endergonic; exergonic
	C.	spontaneous; exergonic

Question 7

When an enzyme catalyzes a reaction

		A. it raises the activation energy of the reaction.
		B. it lowers the activation energy of the reaction.
		C. it is used once and discarded.

Question 8

Which of the following statements regarding enzyme function is false?

		A. An enzyme's function depends on its three-dimensional shape.
		B. Enzymes are very specific for their substrates.
		C. Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction

Carbon disulfide (cs2) has the unusual ability to dissolve several non metals as well as rubbers and resins. What are the boiling and freezing points of a solution consisting of 8.44g of phosphorus (p4) dissolved in 60.0g of cs2?

bromine br2(l) is more soluble in dichloromethane

T. The solublity of ones fn re and decreasing pressuure (1) increasing pressure and increasing temperature (3) decreasing temperature and increasing pressure (2) ally decreases with increasing temperature and decreasing pressure (4) decreasing temperature and decreasing pressure. 8. When a nonvolatile solute s uch as ammonium sulfate is dissolved in a solvent like water, one of the (1) a decrease in the boiling point of the liquid (2) an increase in the vapor (4) a decrease in the observed effects is pressure of the solvent freezing point of the liquid (3) an increase in the vapor pressure of the solute . In which of the following solvents would you expect kBr to be most soluble? (1) CClu (carbon tetrachloride) 0. Calculate the mass percent of HOCH-CH2OH in a solution made by dissolving 6.4 g of HOCHCH20H in 11. During osmosis (1) pure solutes diffuse through a membrane but solvent does not (2) pure solvent (2) CHsCH2OH (ethanol) (3) CaHe (benzene (4) CoH14 (hexane) 48.2 g of water. (1)13.3% (2) 6.9% (3) 7.4% (4) 11.7% diffuses through a membrane but solutes do not (3) pure solvent and a solution both diffuse at the same time through a membrane (4) gases diffuse through a membrane into a solution and build up pressure 12. Which of the following gases is expected to have a highest solubility in water? (1) HCI (2) N2 (3) CH (4) O2 13. How many grams of water are needed to dissolve 27.8 g of ammonium nitrate NH NOs in order to prepare a (1)0.157 g (2) 769 g (3) 36.2 9 0.452 m solution? The molar mass of NH4NOs is 80.04 g/mol. (4) 57.0 g (1) enough solvent to make 14. To make a 3.0 m solution, one could take 3.00 moles of solute and add L of solution (2) enough solvent to make 1.00 kg of solution (3) 1.00 L of solvent (2) 1.00 kg of solvent 15. What volume of 2.00 M CHOH solution is needed to provide 0.500 mol of CHJOH? (1)3,.12 mL (2) 10.0 mL (3) 167 mL (4) 250 mL 16. Assuming 100% dissociation, which ofthe follow ng compounds is listed correctly with its van't Hoff factor? (4) Ala(SO4), i-5 (2) NH4N03, i#3 (3) Sucrose, i:0 (1) NaS0+/-2 17. Calculate the van't Hoff factor of NasPO in a 0.40 m solution whose freezing point is -2.6C. 15 pts]

SAFS 421 Lecture Notes - Lecture 3: Casparian Strip, Photosynthesis, Dew Point

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