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Flashcards in Chapter 3.3 Deck (11)
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What is the Flagella?

Tail of the sperm - only functional flagellum

-Whiplike structure with axoneme identical to cilium
-much longer than cilium
-stiffened by coarse fibers that supports the tail

-movement is more undulating, snakelike
-no power stroke or recovery stroke as in cilia


What is Filtration?

process in which particles are driven thorough a selectively permeable membrane by Hydrostatic Pressure (force exerted on a membrane by water)

Ex: filtration of nutrients though gap blood capillary walls into tissue fluids. Filtration of wastes from the blood in the kidneys while holding back blood cells and proteins


What is Simple Diffusion?

The net movement of particles from are of high concentration to area of low concentration

-Due to their constant spontaneous motion
-Also knows as movement down the concentration gradient (concentration of a substance differs from one point to another)


Describe Diffusion Rates

factors affecting diffusion rate though a membrane:
-temperature (^ temp ^ motion of particles)
-molecular weight (larger molecules move slower)
-steepness of concentrated gradient
-membrane surface area
-membrate permeability


Describe Membrane Permeablity

Diffusion though lipid bilayer:
-nonpolar hydrophobic, lipid-soluble substances diffuse though lipid layer

Diffusion though channel proteins:
-water and charged hydrophilic solutes diffuse though channel proteins in membrane

Cells control permeability by regulating number of channel proteins or by opening and closing gates


What is Osmosis?

Flow of water from one side of a selectively permeable membrane to the other:

-High concentration to low concentration
-Reversible attraction of water to solute particles forms hydration spheres
-Makes those water molecules less available to diffuse back to the side from which they came


What are Aquaporins?

Channel proteins specialized for passage of water
-Cells can increase the rate of osmosis by installing more aquaporins, decrease rate by removing them

-significant amounts of water diffuse even though the hydrophobic, phospholipid regions of the plasma membrane


What is Osmotic Pressure?

Amount of Hydrostatic pressure required to stop osmisis

-Osmosis slows due to hydrostatic pressure

-heart drives water out of capillaries by reverse osmosis - Capillary Filtration


What is Osmole?

one osmole = 1 mole of dissolved particles.

1M NaCl (1 mole Na+ ions + 1 mole Cl- ions) thus 1M NaCl=2 osm/L


What is Osmolarity?

Number of osmoles of solute per liter of solution


What is Osmolality?

Number of osmoles of solute per kilogram of water

Physiological solutions are expressed in Milliosmoles per liter (mOsm/L)

Blood plasma = 300 mOsm/L

osmolality similar to osmolarity at concentration of body fluids - less that 1% difference