Chapter 7 reading quiz

A defect in which of the following molecules would dramatically reduce the rate of diffusion of water across cell membranes?

aquaporins

an animal cell that lacks carbohydrates on the external surface of the plasma membrane would likely be impaired in which of the following functions?

cell-cell recognition

Which of the following results is most likely when a plant cell is submerged in a hypertonic solution?

plasmolysis will shrink the interior of the cell

In which of the following ways do membranes of a eukaryotic cell vary?

Certain proteins are unique to each membrane

In what way do the membranes of a eukaryotic cell vary?

Certain proteins are unique to each membrane.

Which of the following types of molecules are least likely to diffuse through the phospholipid bilayer of a cell membrane?

Small ions

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 is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal? a. A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose. b. The sodium ions are moving down their electrochemical gradient while glucose is moving up. c. The cotransporter can also transport potassium ions. d. Sodium ions can move down their

A substance that blocks sodium ions from binding tot he cotransport protein will also block the transport of glucose

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.

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?

Amphipathic nature

Which of the following types of molecules are most likely to lack hydrophilic domains?

Cholesterol

Which of the following statements best describes a characteristic feature of a carrier protein in a plasma membrane?

It exhibits specifically for a particular type of molecule

Which of the following statements best explains why the sodium-potassium pump is an electromagnetic pump?

It generates voltage across the membrane

Which of the following organelles plays a primary role in the digestion of bacteria engulfed by white blood cells

Lysosomes

Which of the following membrane activities requires energy for ATP hydrolysis?

Movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Which of the following molecules would likely diffuse through the lipid bilayer of a plasma membrane most rapidly?

O2

Select the correct statement about osmosis

Osmosis is the diffusion of water molecules across a selectively permeable membrane.

which of the following particles could diffuse easily through a cell membrane?

Oxygen (O2)

Which of the following processes is used by white blood cells when engulfing bacteria?

Phagocytosis

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 best describes the difference between pinocytosis and recepto-mediated endocytosis?

Pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity

What water regulation adaptions might have evolved in protists in hypertonic habitats such as the great salt lake?

Protists would have more higher permeable membranes than those in hypotonic or isotonic environments, allowing more water to enter the cell. also, they could possibly develops higher salt concentration within the cell to retain water

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 results is most likely result of a portion of an animals blood is replaced with distilled water?

The animals red blood cells will swell and possibly burst because the blood has become hypotonic compared to the cells

What statement is correct?

The contents of a red blood cell are hyper so motif to distilled water

Which of the following statements best describes how unsaturated fatty acids increase membrane fluidity at lower temperatures?

The double bonds form kinks in the fatty acid tails, preventing adjacent lipids from packing tightly

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 amphipathci proteins

Which of the following statements best explains how the membranes in winter are able to remain fluid in extremely cold temperatures?

The membranes contain an increased proportion of unsaturated phospholipids

which of the following statements about osmosis is correct?

The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis.

Which of the following statements best describes characteristic activities of a sodium-potassium pump?

The pump moves three sodium ions out of the cell and 2 potassium ions into the cell using ATP hydrolysis

What factors affect the rate of osmotic movement of water?

The rate of osmosis increases with increasing differences in solute concentrations between 2 solutions separated by a selectively permeable membrane

Cell membranes have distinct inside and outside faces. Which of the following statements is the most plausible explanation for the asymmetrical nature of the two layers of the membrane?

The two layers of a cell membrane face different environments and carry out different functions

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

Which of the following statements describes the role of the transport protein in facilitated diffusion?

Transport proteins allow solutes to love passively down their concentration gradients across the membrane

True or false? Osmosis is a type of diffusion.

True (Osmosis is the diffusion of water across a selectively permeable membrane.)

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.

True (The hydrophilic, or water-loving, portion of a phospholipid is the polar head, whereas the hydrophobic portion is the nonpolar tail.)

What happens when two solutions separated by a selectively permeable membrane reach osmotic equilibrium?

Water molecules move between the two solutions, but there is no net movement of water across the membrane.

Which of the following molecular movements is due to diffusion or osmosis?

When a plant cell is placed in concentrated salt water, water moves out of the cell.

the force driving simple diffusion is __ , while the energy source for active transport is ____

a concentration gradient; ATP hydrolysis

Which of the following factors would tend to increase membrane fluidity?

a greater proportion of unsaturated phospholipids

If the concentration of phosphate in the cytosol is 2.0 mM and the concentration of phosphate in the surrounding fluid is 0.1 mM, how could the cell increase the concentration of phosphate in the cytosol?

active transport

Which of the following statements correctly describes some aspect of exocytosis and endocytosis?

both change the surface area of the plasma membrane

Which of the following statements is true with regards to this animation?

both sodium and potassium ions are transported against their concentration gradients

The gradients of the other ions are most likely established by which of the following?

contransport proteins

The movement of glucose into a cell against a 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

According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly

embedded in a lipid bilayer

Several epidemic microbial diseases of earlier centuries incurred high death rates because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following?

hydrating drinks that include high concentrations of salts and glucose

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?

hypotonic

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are

hypotonic to fresh water but hypertonic to the salt solution

which of the following statements best describes a characteristic feature of osmosis?

in osmosis, water moves across a membrane from areas of lower solute concentration to areas of higher concentration

Endocytosis moves materials _____ a cell via _____.

into ... membranous vesicles

Diffusion of ions across membranes through specific ion channels is driven by

ion electrochemical gradients

what will happen to a red blood cell if it is placed in pure water?

it will swell because the water in the beaker is hypotonic to the cytoplasm of the rbc

The voltage across a membrane is called a

membrane potential

A white blood cell engulfing a bacteria is an example of

phagocytosis

An organism with a cell wall would most likely be unable to take in materials through

phagocytosis

Which of the following statements best explains the observation that proton pumps are used by organisms in every domain of life?

proton gradients across a membrane were used by cells that were the common ancestor of all three domains of life.

You can recognize the process of pinocytosis when _____.

the cell is engulfing extracellular fluid

The permeability of a biological membrane to a specific polar solute may depend of which of the following?

the types of transport proteins in the membrane

the reason that lipids and proteins are free to move laterally?

there are only weak hydrophobic interactions in the interior of the membrane

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