2. Cell Chemistry &amp; Cell Components

The fluid mosaic model of the membrane proposed that membranes:

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Why are cell membranes composed primarily of hydrophobic molecules?

Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct?

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The plasma membrane is referred to as a "fluid mosaic" structure. Which of the following statements about that model is true?

Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the plasma membrane would cholesterol most likely be found?

Which of the following statements concerning carbohydrates associated with the plasma membrane is correct?

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Consider the currently accepted fluid mosaic model of the plasma membrane. Where in the membrane would carbohydrates most likely be found?

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Which statement about the sidedness of the plasma membrane is correct?

What is a fiber composite? How do cellular fiber composites resemble reinforced concrete?

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According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly a. spread in a continuous layer over the inner and outer surfaces of the membrane. b. confined to the hydrophobic interior of the membrane. c. embedded in a lipid bilayer. d. randomly oriented in the membrane, with no fixed inside-outside polarity.

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Which of the following factors would tend to increase membrane fluidity? a. a greater proportion of unsaturated phospholipids b. a greater proportion of saturated phospholipids c. a lower temperature d. a relatively high protein content in the membrane

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Which best describes the structure of a cell membrane? a. proteins between two bilayers of phospholipids b. proteins embedded in a bilayer of phospholipids c. a bilayer of protein coating a layer of phospholipids d. cholesterol embedded in a bilayer of phospholipids

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Which of the following is one of the major components of the plasma membrane of a plant cell? a. phospholipids b. cellulose fibers c. collagen fibers d. pectins

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Which of the following best describes the arrangement of the main component of the plasma membrane?

a. A monolayer of phospholipids with the phosphate heads facing the cytosol and the fatty acid tails facing the extracellular fluid

b. A bilayer of phospholipids with the phosphate heads facing the cytosol and extracellular fluid, and the fatty acid tails facing one another

c. A bilayer of phospholipids with the phosphate heads of one layer facing the fatty acid tails of the other

d. A bilayer of phospholipids with a layer of triglycerides sandwiched in the middle

Mark the following statements about the plasma membrane as true or false. If a statement is false, correct it to make a true statement.

a. Integral membrane proteins generally span the width of the plasma membrane, whereas peripheral proteins are found on only one side of the membrane.

Mark the following statements about the plasma membrane as true or false. If a statement is false, correct it to make a true statement.

b. Cholesterol provides the plasma membrane with stability in the face of changing ion concentrations.

Mark the following statements about the plasma membrane as true or false. If a statement is false, correct it to make a true statement.

c. Membrane cholesterol is vital for cell-cell recognition.

Open Question

Mark the following statements about the plasma membrane as true or false. If a statement is false, correct it to make a true statement.

e. The overall structure of the plasma membrane is a mosaic with the components locked tightly in place.

Explain how the members of the endomembrane system interact.

Multiple Choice More than one choice may apply. Which of the following would you expect to find in or on cells whose main function is absorption? a. b. c. d.

Multiple Choice More than one choice may apply. Which of the following are possible functions of the glycoproteins in the plasma membrane? a. Determination of blood groups b. Binding sites for toxins or bacteria c. Aiding the binding of sperm to egg d. Increasing the efficiency of absorption