BSC 2011 Lecture Notes - Lecture 10: Cellular Respiration, Nephridium, Nephron

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copperalligator485

4 Apr 2016

School

University of Florida

Department

Biology - Biological Sciences

Course

BSC 2011

Professor

Gerlach, Nicole

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Document Summary

Regulate overall solute concentraions, or osmolarity, in extracellular luid. Maintain speciic solutes (ca2+, hydrogen ions, sodium ions, glucose) at appropriate levels. Result is osmoic equilibrium for opimal funcion o the organism and cells. Osmosis is movement of water across a selecively permeable membrane. Water will always move from an area of less solute (more water) to an area of more solute (less water). If the osmolarity on both sides of the membrane are equal, the cell and the soluion are isoosmoic (or isotonic) If there is more solute inside of the cell, the inside of the cell is hyperosmoic to the soluion. If there is more solute outside of the cell, the inside of the cell is hypoosmoic to the soluion. If the osmolarity of the extracellular luid is diferent than the cytoplasm, water will move into or out of the cells via osmosis, and cells may be damaged. Animals have diferent ways of meeing osmoic challenges.

Related Questions

A cell with internal osmolarity of 300 mOsM is placed in a solution that is 300 mOsM. The cell swells and bursts. Which of the following statements is true? (1 point) Water moved out of the cell down its osmotic gradient. When the cell is first placed into the solution, the solutes inside the cell have the exact same chemical composition as the solutes outside the cell. The cell membrane is more permeable to the solutes that are initially outside the cell than the solutes that are initially inside the cell. There is no net movement of water into or out of the cell.

amethystwhale300

1) This is a thermodynamics questions

In your body, normal osmolarity of blood serum is just under 0.3 molar. Because cell membranes are permeable to water, the osmolarity of intracellular fluid is approximately equal to that of extracellular fluid (though the intracellular and extracellular composition in terms of specific ions and proteins is quite different). As an aside, measurement of osmolarity of serum is an important clinical test used to check for dehydration or other imbalances of water and electrolytes.

a) In the supplemental information, the osmosis example presented involves sucrose as a solute, but the van't Hoff equation also applies for other solutes. Using this formula (â = cRT, where â is the excess pressure), calculate the osmotic pressure associated with 0.3 molar concentration of osmolytic particles (e.g., ions, proteins, or other dissolved particles) in contact with pure water through a semi-permeable membrane at physiological temperature of 310 K. Express your results in atmospheres of pressure (1 atmosphere of pressure is 1.0x10⁵ Pascal, where 1 Pascal is a Newton/m²).

b) A biological cell membrane is a bilayer of phospholipid molecules, only a few nanometers thick, and can basically be thought of much like a soap bubble, except immersed in aqueous solution. If cells are placed in pure water, they often swell and burst in just a few minutes. Explain why this would happen.

grayporcupine495

Please help! Not sure about these questions..thanks

Which can cross the phospholipid bilayer of a membrane without assistance from transport proteins?

	A.	Ions such as Na+.
	B.	Small hydrophobic molecules such as O2.
	C.	Small hydrophilic molecules such as glucose.
	D.	Any small molecule or ion.

QUESTION 2

Which transport process requires a cell to expend energy?

	A.	Moving a solute up its concentration gradient.
	B.	No transport processes require energy.
	C.	Moving a solute either up or down its concentration gradient.
	D.	Moving a solute down its concentration gradient.

QUESTION 3

Imagine a cell whose membrane is permeable to water, but impermeable to solute X. If solute X is more concentrated outside the cell than inside, which way will water move by osmosis?

	A.	Water will not move in either direction, in or out of the cell.
	B.	Water will move equally in both directions, in and out of the cell.
	C.	Water will leave the cell.
	D.	Water will enter the cell.

QUESTION 4

The cellular structure that encloses the DNA/genes is the

		ribosome.
		plasma membrane.
		nucleus.
		mitochondrion.

QUESTION 5

The part of metabolism that builds larger, more complex molecules or structures from smaller, simpler components is

	A.	anabolism.
	B.	catabolism.
	C.	catalysis.
	D.	hydrolysis.

QUESTION 6

In an exergonic reaction

	A.	the reactants have more energy than the products, so energy is absorbed.
	B.	the reactants have more energy than the products, so energy is released.
	C.	the reactants have less energy than the products, so energy is released.
	D.	the reactants have less energy than the products, so energy is absorbed.

BSC 2011 Lecture Notes - Lecture 10: Cellular Respiration, Nephridium, Nephron

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