Chapter 7

Transport protein

The transport protein facilitates the movement of solute across the plasma membrane, while a solute is crossing the plasma membrane.

Endocytosis moves materials _____ a cell via _____. out of ... diffusion out of ... membranous vesicles into ... a transport protein into ... facilitated diffusion into ... membranous vesicles

into ... membranous vesicles

A white blood cell engulfing a bacterium is an example of _____. exocytosis facilitated diffusion receptor-mediated endocytosis pinocytosis phagocytosis

phagocytosis

What kinds of molecules pass through a cell membrane most easily? ionic small and hydrophobic large polar large and hydrophobic

small and hydrophobic

You are working on a team that is designing a new drug. For this drug to work, it must enter the cytoplasm of specific target cells. Which of the following would be a factor that determines whether the molecule selectively enters the target cells? the phospholipid composition of the target cells' plasma membrane the similarity of the drug molecule to other molecules that are transported into the target cells the concentration of the drug molecule that is transported in the blood the nonpolar, hydrophobic nature of the drug molecule

the similarity of the drug molecule to other molecules that are transported into the target cells

The permeability of a biological membrane to a specific polar solute may depend on which of the following? the amount of cholesterol in the membrane the types of transport proteins in the membrane the phospholipid composition of the membrane the presence of unsaturated fatty acids in the membrane the types of polysaccharides present in the membrane

the types of transport proteins in the membrane The lipid bilayer will be impermeable or very poorly permeable to polar or charged solutes. The presence of the correct transport protein will determine the permeability.

Biologists use the fluid mosaic model to describe membrane structure. Which statements about the fluid mosaic structure of a membrane are correct? Select the three correct statements. Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane. The kinky tails of some proteins help keep the membrane fluid by preventing the component molecules from packing solidly together. Membranes include a mosaic, or mix, of carbohydrates embedded in a phospholipid bilayer. The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center. The diverse proteins found in and attached to membranes perform many important functions.

1.Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane. 2.The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center. 3.The diverse proteins found in and attached to membranes perform many important functions.

Active and passive transport of solutes across a membrane typically differ in which of the following ways? Active transport is usually down the concentration gradient of the solute, whereas passive transport is always against the concentration gradient of the solute. Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy. Active transport is always faster than passive transport. Active transport uses protein carriers, whereas passive transport uses carbohydrate carriers. Active transport is used for ions, passive transport is used for uncharged solutes.

Active transport always involves the utilization of cellular energy, whereas passive transport does not require cellular energy. *Active and passive transport can be distinguished by whether or not they use cellular energy.*

Facilitated diffusion is a type of _______. passive transport pinocytosis phagocytosis active transport

passive transport *During facilitated diffusion, the cell is not expending energy to move the particles across the membrane; therefore, facilitated diffusion is a form of passive transport.*

You can recognize the process of pinocytosis when _____. the cell is engulfing a large particle the cell is engulfing extracellular fluid a receptor protein is involved

the cell is engulfing extracellular fluid

The force driving simple diffusion is _____, while the energy source for active transport is _____. the concentration gradient; ADP phosphorylated protein carriers; ATP the concentration gradient; ATP transmembrane pumps; electron transport

the concentration gradient; ATP