BIOC40H3 Chapter Notes - Chapter 4: Hydraulic Conductivity, Hydrostatics, Tracheid

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crimsonwoodchuck49

2 Aug 2012

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In sandy soils, the spaces between particles are so large that water tends to drain from them and remain only on the particle surfaces and at interstices between particles. In clay soils, the channels are small enough that water is retained against the forces due to gravity. The moisture holding capacity of soil is called field capacity. Field capacity is water content of soil after it is saturated with water and excess has been drained away. Clay soils or soils with high humus content have large field capacity. Sand particles are larger and have less surface area per gram. Clay particles are smaller and have more surface area per gram. Negative hydrostatic pressure in soil water lowers soil water potential. The osmotic potential ( s) of soil water is usually neglible because solute concentrations are low i. e. -0. 02mpa. For soils with substantial concentrations of salt s can be significant i. e. -0. 2 mpa or lower.

Related Questions

1. At 50% of field capacity, the matric potential of clay soils is:

A. less negative than loam and sand

B. more negative than sand and less negative than loam

C. more negative than loam and sand

D. less negative than sand and more negative than loam

E. matric potential is equivalent for all soils at the same water content

2. Factors that affect percentage base saturation of soil include (choose any/all that apply):

A. clay content

B. parental material

C. total precipiation

D, soil water content

E. depth of O horizon

F. soil microbial respiration

G. soil pH

3.Which of the following statements about symbiotic nitrogen fixation is true (select any/all that apply)?

A. It requires a symbiotic association between a plant and either a prokaryote or fungus.

B. it is only found in the plant family Fabaceae

C. It can be an important source of N to soils and protein to herbivores.

D. It occurs in specialized root structures of the host plant.

E. it is found in all species of Fabaceae

F.. it is found throughout the plant kingdom

G. Symbiotic N-fixers require photosynthetic carbon from their hosts

Why is it beneficial to plants that soil particles have negativelycharged surfaces?
A. It helps maintain the water potential of thesoil
B. Toxic metals are trapped and kept away from theplants.
C. They capture negatively-charged ions
D. Negatively-charged ions are pushed towards theroots
E. They attract positively-charged ions and prevent them from beingwashed deep into the soil.

Explain why it is correct!

taupebee805

Cholesterol is transported in the bloodstream in lipoproteinparticles. There are several classes of lipoprotein particles, butone of the most important classes is called Low-densitylipoproteins (LDL). LDL particles are composed of a single moleculeof a large protein called apolipoprotein, as well as thousands ofcholesterols molecules and phospholipids. Part of theapolipoprotein forms the surface of the particles and faces theaqueous phase, while other parts face the hydrophobic interior ofthe particle where they interact with cholesterol and thehydrophobic tails of the phospholipids. When cells need additionalcholesterol, they produce a receptor protein on the surface oftheir plasma membrane that binds to the apolipoprotein andinitiates the uptake of LDL particles into the cell via a processcalled endocytosis.

1. What is the likely reason that LDL particles are used totransport cholesterol in the blood stream?

a. Cholesterol in LDL particles easily inserts into lipidbilayers

b. Cholesterol id largely insoluble in aqueous solutions

c. Cholesterol is synthesized within LDL particles

d. LDL particles can form lipid rafts in the lipid bilayer

2. What is the most likely location of phospholipids in LDLparticles?

a. Bound to the hydrophilic domain of apolipoprotein

b. In the lipid bilayer that surrounds LDL particles

c. On the surface interacting with the aqueous environment aswell as interacting with the hydrophobic core of the particle

d. Within the hydrophobic core of the particle

3. What best describes the class of protein that apolipoproteinbelongs to?

a. Amphipathic proteins

b. Cell surface proteins

c. Membrane associated protein

d. Multipass membrane proteins

4. What kind of molecule on the surface of the cell would bemost likely to serve as a receptor for LDL particles?

a. a cholesterol binding protein

b. a glycolipid

c. a phospholipid

d. trans membrane protein

5. What conditions would be most likely to trigger increaseduptake of LDL particles by cells?

a. increased glycolipid synthesis

b. increased plasma membrane growth

c. increased protein secretion

d. increase protein synthesis

BIOC40H3 Chapter Notes - Chapter 4: Hydraulic Conductivity, Hydrostatics, Tracheid

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