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Which one of the following biological macromolecules is least likely to be a component of a biomembrane?
D)Nucleic acids
E)All of the choices are common components of biomembranes.
A solute crossing a biomembrane from a region of low concentration to a region of high concentration with the aid of a transport protein and energy is most accurately referred to as
A)selective permeability.
B)active transport.
C)passive diffusion.
D)facilitated diffusion.
Which of the following is not a type of transport protein?
E)All of the choices are forms of membrane transport proteins.
Which of the following is not an integral membrane protein?
A)Transmembrane protein
B)Lipid-anchored protein
C)Transmembrane segment
D)Extrinsic proteins
E)All of the choices are integral membrane proteins.
Under what conditions would a biomembrane be the most fluid at 37°C?
A)Long unsaturated fatty acyl tails plus cholesterol
B)Short unsaturated fatty acyl tails and no cholesterol
C)Short saturated fatty acyl tails and no cholesterol
D)Short unsaturated fatty acyl tails plus cholesterol
E)Long saturated fatty acyl tails plus cholesterol
If the Frye and Edidin experiment was repeated using an incubation temperature of 30°C instead of 37°C, mouse H-2 protein would still be distributed evenly on both sides of the hybrid cell, but would take longer for the distribution to complete.
Which of the following statements does not represent a reason why integral membrane proteins might be restricted in their movements?
A)It is energetically unfavorable for the hydrophilic region of a membrane protein to cross the hydrophobic interior of the membrane.
B)The cytosolic face of an integral membrane protein can be linked to the cell's cytoskeleton.
C)Proteins are larger molecules than lipids and therefore move more slowly than lipids through a lipid bilayer.
D)Integral membrane proteins can be attached to molecules in the extracellular space.
E)All of the choices describe possible reasons for the restricted movement of integral membrane proteins.
The technique most commonly used to study the interior of a biomembrane is known as
A)transmission electron microscopy.
B)fluorescence microscopy.
C)freeze-fracture electron microscopy.
D)scanning electron microscopy.
E)fluorescence recovery after photo bleaching.
Arrange the following molecules in order from most likely to least likely to pass through a biomembrane.
  1. glucose
  2. carbon dioxide
  3. Water
  4. K+ (Potassium ion)
A)iv > i > iii > ii
B)iii > ii > i > iv
C)ii > iii > iv > i
D)iv > iii > i > ii
E)ii > iii > i > iv
True or False: The movement of water across a semipermeable membrane to balance solute concentrations is called osmosis and requires energy input.
A beaker of water is divided into two compartments, A and B, by an artificial lipid bilayer. The concentration of Na+ in compartment A is 1.0 M, while the concentration of Na+ in compartment B is 1.5 M. With regards to Na+ concentration, compartment A would be referred to as __________, while compartment B would be referred to as __________.
A)isotonic; hypertonic
B)hypertonic; hypotonic
C)hypotonic; isotonic
D)hypotonic; hypertonic
E)hypertonic; isotonic
How does a freshwater organism like a paramecium maintain proper osmotic balance?
A)Paramecium have a rigid cell wall which prevents water loss.
B)The cell membranes of paramecium contain special water pumps to move water into the cytoplasm.
C)The cell membranes of paramecium contain special water pumps to move water out of the cytoplasm.
D)Paramecium have contractile vacuoles which accumulate water, fuse with the plasma membrane, and discharge the water into the extracellular environment.
E)No special mechanism is necessary because the cytoplasm is isotonic with the extracellular environment.
A transmembrane channel that opens and closes in response to the direct binding of a molecule to the channel protein itself is referred to as a(n)
A)mechanosensitive channel.
C)voltage-gated channel.
D)ligand-gated channel.
E)phosphorosensitive channel.
Carriers that bind two or more molecules or ions and transport them in opposite directions are called __________, while carriers that bind two or more molecules or ions and transport them in the same direction are called __________.
A)symporters; cotransporters
B)uniporters; symporters
C)symporters; antiporters
D)antiporters; uniporters
E)antiporters; symporters
True or False: Existing proton (H+) gradients frequently provide the energy required to move nutrients against their concentration gradients.
Which one of the following statements about Na+/K+-ATPase pumps is incorrect?
A)Na+/K+-ATPase pumps are an example of an electrogenic pump.
B)A typical animal cell utilizes thousands of Na+/K+-ATPase pumps to maintain ATPase gradients across the cell membranes.
C)The Na+/K+-ATPase pump results in 2 K+ being released into the cytosol and 3 Na+ being released into the extracellular space.
D)A Na+/K+-ATPase pumps alternates between two different conformations known as E1 and E2.
E)Some animal cell types, like neurons, utilize a majority of their ATP to operate pumps like the Na+/K+-ATPase pump.
Which of the following is not a function of an electrochemical gradient?
A)Export of waste products.
B)Contraction of muscle fibers.
C)Synthesis of ATP.
D)Transmission of nerve impulses.
Vesicles destined for exocytosis are typically derived from
B)smooth endoplasmic reticulum.
D)the Golgi apparatus.
Which one of the following statements about endocytosis is incorrect?
A)Endocytic vesicles can be formed when a receptor molecule binds a specific cargo molecule.
B)All cell types are capable of phagocytosis, a form of endocytosis.
C)Internalization of extracellular fluid is a form of endocytosis.
D)Endocytosis is an invagination of the plasma membrane.
E)All of these statements about endocytosis are correct.
True or False: Bacteria invading a mammalian host are often removed when the host's immune system cells engulf the bacteria and fuse with lysosomes, which provide the energy for destruction of the bacteria.

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