Why does a surgeon irrigate a surgical wound from which a tumor has been removed with sterile distilled water rather than with sterile isotonic saline?
Solution A is hyper osmotic to solution B. If solution A is separated from solution B by a selectively permeable membrane, does water move from solution A into solution B or vice versa? Explain.
A researcher wants to determine the nature of the transport mechanism that moved substance X into a cell. She could measure the concentration of substance X in the extra cellular fluid and within the cell, as well as the rate of movement of substance X into the cell. She does a series of experiments and gathers the data shown in the graph. Choose the transport process that is consistent with the data.
- active transport
- facilitated diffusion
- not enough information to make a judgment
Graph depicting the rate of movement of substance X from a fluid into a cell (y axis) versus the concentration of substance X within the cell minus the concentration outside the cell (x axis). At point A the extra cellular concentration of substance X is equal to the intracellular concentration of substance X (designated 0 on the x axis).
A dialysis membrane is selectively permeable, and substances smaller than proteins are able to pass through it. If you wanted to use a dialysis machine to remove only urea (a small molecule) from blood, what could you use for the dialysis fluid?
- a solution that is isotonic and contains only large molecules, such as protein
- a solution that is isotonic and contains the same concentration of all substances except that it has no urea
- distilled water, which contains no ions or dissolved molecules
- blood, which is isotonic and contains the same concentration of all substances, including urea
Predict the consequence of a reduced intracellular K+ concentration on the resting membrane potential.
If you had the ability to inhibit mRNA synthesis with a drug, explain how you could distinguish between proteins released from secretory vesicles in which they had been stored and proteins released from cells in which they have been newly synthesized.
Given the following data from electron micrographs of a cell, predict the major function of the cell:
- moderate number of mitochondria;
- well-developed rough endoplasmic reticulum;
- moderate number of lysosomes;
- well-developed Golgi apparatus;
- dense nuclear chromatin;
- numerous vesicles.