Chapter 7 Biology
In what way do the membranes of a eukaryotic cell vary?
Certain proteins are unique to each membrane.
Which of the following statements best explains why the sodium-potassium pump is an electrogenic pump?
It generates voltage across the membrane.
Which of the following statements best describes a characteristic feature of diffusion?
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
Which of the following statements best describes a characteristic of biological membranes?
Phospholipids move laterally within the plane of the membrane.
Which of the following statements most accurately compares primary factors responsible for simple diffusion versus active transport?
Simple diffusion is driven by a concentration gradient, while active transport is driven by ATP hydrolysis.
Which of the following statements best describes the structure of a membrane based on the fluid mosaic model?
The membrane is composed of a fluid bilayer of phospholipids with embedded amphipathic proteins.
Which of the following statements about a typical plasma membrane is correct?
The two sides of the plasma membrane have different lipid and protein composition.
Which of the following statements best describes a characteristic feature of integral membrane proteins?
They are amphipathic, with at least one hydrophobic region
The force driving simple diffusion is ________, while the energy source for active transport is ________.
a concentration gradient; ATP hydrolysis
Active and passive transport of solutes across a membrane typically differ in which of the following ways?
active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy
An animal cell that lacks carbohydrates on the external surface of its plasma membrane would likely be impaired in which of the following functions?
cell-cell recognition
The movement of glucose into a cell against its concentration gradient is most likely to be accomplished by which of the following?
cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis
Which of the following is least likely to be important in holding the components of a biological membrane together?
covalent interactions between the phospholipid and protein components of the membrane
Which of the following organelles plays a primary role in the digestion of bacteria engulfed by white blood cells?
lysosomes
In receptor-mediated endocytosis, membrane receptors bind to molecules outside of the cell. Immediately following endocytosis where will the membrane receptors be located?
on the inside surface of the vesicle
Which of the following processes is used by white blood cells when engulfing bacteria?
phagocytosis
Which of the following statements best describes the difference between pinocytosis and receptor-mediated endocytosis?
pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity
Which of the following best describes the structure of a biological membrane?
two layers of phospholipids, with proteins either crossing the layers or on the surface of the layers