When blood supplies oxygen and food to a cell surface and these molecules diffuse across, we might expect some "resting time." However, if we inspected most cell membranes in a living human body, we would find a nearly continuous flow of substances back-and-forth across the plasma membrane. Which of the following is NOT a reason why?
A) Cell metabolism is constantly using up oxygen and raw materials; this lowers their concentration so more will diffuse into the cell. B) Cell metabolism is constantly producing waste molecules; this increases their concentration so more will diffuse out of the cell.
C) Cells produce useful secretions; this increases their concentration and more will diffuse out of the cell.
D) Cell metabolism constantly produces carbon dioxide in respiration; this increases its concentration so more will diffuse out of the cell.
E) Cells are living entities and in order to live can never "rest".
Ans: E) Cells are living entities and in order to live can never "rest".
You might also like to view...
Distilled water would be considered ____ to body cells
a. isotonic b. hypertonic c. hypotonic d. protonic e. aquatonic
Short-day plants
a. flower in early spring. b. will not bloom until they have been exposed to a dark period longer than a critical length. c. flower in the fall. d. will not bloom if their dark period is interrupted by a short pulse of intense red light. e. do all of these.
FGA is one of the STRs that are used to compare DNA between different people. Why is FGA useful for comparing DNA between different people?
A) FGA varies in the number of repeats between different people. B) FGA varies in sequence between different people. C) FGA is only present in some peoples' genomes. D) FGA is present in different places in different peoples' genomes.
Biofilms provide pathogens with an adhesion mechanism and aid in resistance to antimicrobial agents
Indicate whether the statement is true or false