Bio Test #2 corrections
An open beaker of pure water has a water potential of
zero
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly
CO2
A balloon permeable to water but not to glucose contains a 10% glucose solution. A beaker container contains a 5% glucose solution. Which of the following is true
The solution in the balloon is hypertonic relative to the solution in the beaker
Which statement is true
a cell placed in a hypotonic solution will swell
Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold
by increasing the percentage of cholesterol in the membrane
Which of the following is NOT a form of active transport
diffusion
The presence of cholesterol in the plasma membranes of some animals
enables the membrane to stay fluid more easily when cell temperatures drops
Glucose diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose-rich food into their glucose-poor cytoplasm. Using this information, which transport mechanism is most probably functioning in the intestinal cells
facilitated diffusion
If a plasma membrane were compared to a sandwich ____ would be considered the filling
hydrophobic tails
A cell whose cytoplasm has a concentration of 0.02 molar glucose is placed in a test tube of water containing 0.02 molar glucose. Assuming that glucose is not actively transported into the cell, which of the following terms describes the tonicity of the eternal solution relative to the cytoplasm of the cell?
isotonic
Which of the following statements is correct about diffusion
it is a passive progress in which molecules move from a region of high concentration to a region of lower concentration
All of the following cellular activities require ATP energy except
movement of O2 into the cell
In receptor-mediated endocytosis, receptor molecules initially project to the outside of the cell. Where do they end up after endocytosis
on the inside surface of the vesicle
Diffusion is an example of
passive transport
Which of the following processes includes all others
passive transport
White blood cells engulf bacteria through what process
phagocytosis
_____ is to eating as ____ is to drinking
phagocytosis, pinocytosis
______ are the major lipids of plasma membranes
phospholipids
Why, when mixed with water, do phospholipids spontaneously form membranes
phospholipids have hydrophilic phosphate groups that are attracted to water and hydrophobic fatty acid tails that avoid water
What kinds of molecules pass through a cell membrane most easily
small and hydrophobic
Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that
the fresh water is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
A patient has had a serious accident and lost a lot of blood. in an attempt to replenish body fluids, distilled water-equal to the volume of blood lost-is transferred directly into one of his veins. what will be the most probable result of this transfusion
the patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells
The amount and direction of movement of water in plants can always be predicted by measuring which of the following
water potential
Mammalian blood contains the equivalent of 0.15 M NaCL. Seawater contains the equivalent of 0.45 M NaCL. What will happen if red blood cells are transferred to seawater
water will leave the cells, causing them to shrivel and collapse
