Tonicity and Osmoregulation
Phospholipid Bilayer
Water Potential
Miscellaneous
100
Where would the water in the red blood cell go?
out of the cell.
100
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Which part of the membrane is non polar?
fatty acid tails/inside of the membrane
100
A plant cell has a water potential (Ψ) of −0.6 MPa. It is placed in a solution with a water potential of −0.2 MPa.
In which direction will water move, and will the cell gain or lose water?
Water will move into the cell
100
Why do some molecules need transport proteins to cross the cell membrane?
Some molecules need transport proteins because they are large, polar, or charged and cannot pass through the hydrophobic lipid bilayer on their own.
200
What will happen to the cell if immersed in a hypertonic solution?
Will shrivel and die/lose water.
200
True or False: The phospholipid bilayer can have large polar molecules diffuse through it without carrier proteins.
false
200
A solution contains 0.5 M sucrose at 25°C out in an open container. What is the water potential?
-12.4 bars
200
The endosymbiont theory proposes a model for the evolution of mitochondria. According to the model, an ancestral eukaryote engulfed a small, free-living prokaryotic organism. The engulfed prokaryote then formed an endosymbiotic relationship with the eukaryotic host.
Which of the following observations best supports the model?
(A) Prokaryotes and eukaryotes acquire nutrients from the surrounding environment.
(B) Organelles such as mitochondria and the endoplasmic reticulum have membranes composed of phospholipids.
(C) Mitochondria and some prokaryotes share similar metabolic reactions that produce ATP.
(D) Eukaryotes evolved after prokaryotes and have more complex structures.
(C) Mitochondria and some prokaryotes share similar metabolic reactions that produce ATP.
300
What type of solution is the cells immersed in?
hypotonic
300
True or False: Small uncharged molecules can use simple diffusion to pass through the cell membrane.
True
300
What is the pressure potential of a plant cell, in bars, if the water potential is -4 bars and the solute potential is -5 bars?
1 bar
300
Red blood cells have an internal NaCl concentration of 0.9%. Red blood cells are placed into flasks containing solutions of varying NaCl concentrations. If the solution has a NaCl concentration of 0.5%, identify whether it is isotonic, hypertonic, or hypotonic, and predict what will happen to the blood cells.
The solution is hypotonic, and the blood cells will swell up and lyse.
400
What does Isotonic solution mean?
no net movement of water
400
A glucose molecule requires ________ diffusion to pass through the cell membrane.
facilitated
400
A plant cell with a Ψs of -7.5 bars keeps a constant volume when immersed in an open-beaker solution that has a Ψs of -4 bars. What is the cell's ΨP?
3.5 bars
400
Dialysis tubing permeable only to water is filled with 0.2 M sucrose and placed in a beaker of 0.4 M sucrose. Which of the following best explains the change in the tubing's mass?
(A) Mass increases as water moves to the higher water potential in the tubing.
(B) Mass decreases as water moves to the lower water potential in the beaker.
(C) Mass increases as sucrose moves to the higher concentration in the tubing.
(D) Mass decreases as sucrose moves to the lower concentration in the beaker.
(B) Mass decreases as water moves to the lower water potential in the beaker.
500
What will happen to a PLANT cell if it is place in a hypotonic solution?
Water will enter the cell and become swollen, but the cell will not burst due to the cell wall.(maintains tugor pressure)
500
What molecules can pass through the cell membrane?
Small, non polar and uncharged molecules.
500
The value for water potential in root tissue was found to be -3.3 bars. If you take the root tissue and place it in a 0.1 M solution of sucrose at 20°C in an open beaker, what is the water potential of the solution and in which direction will the net flow of water be?
–2.43 bars
from the sucrose solution into the root tissue
500
The solute potential of a plant cell is -6.5 bar, and its pressure potential is 1.5 bar. The plant cell is placed into a solution with a water potential of -2.5 bar.
What is the water potential of the cell, and in which way will water move?
-5.0 bar; and the water will move into the cell.