PLHS AP Bio 10 Ch 7 Review

Which statement is correct? The contents of a red blood cell are hyperosmotic to distilled water. A solution of distilled water is hypotonic. A solution of seawater is hypertonic.

The contents of a red blood cell are hyperosmotic to distilled water.

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.

Which of these cannot rapidly pass directly through the phospholipids of the plasma membrane? The figure shows the cell membrane. There are some particles outside the cell. The lipid soluble molecule is marked A. The molecule of the water is marked B. The molecule of glucose is marked C. The hydrogen ion is marked D.

B, C, and D

In what way do membranes vary among eukaryotic cells? In what way do membranes vary among eukaryotic cells? Only certain membranes are constructed from amphipathic molecules. Phospholipids are found only in certain membranes. Only certain membranes of the cell are selectively permeable. Certain proteins are unique to each membrane. Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.

Certain proteins are unique to each membrane.

Sort the phrases into the appropriate bins depending on whether they describe exocytosis, endocytosis, or both.

In exocytosis, substances are transported to the plasma membrane in vesicles derived from the endomembrane system. These vesicles fuse with the plasma membrane, releasing the enclosed substances outside the cell. In endocytosis, substances are taken into the cell by folding in of the plasma membrane and pinching off of the membrane to form a vesicle. Notice that in both exocytosis and endocytosis, the transported substances never actually cross the plasma membrane as they leave or enter the cell.

Select the correct statement about osmosis. If a dead cell is placed in a solution hypotonic to the cell contents, osmosis will not occur. Osmotic equilibrium cannot be reached unless solute concentrations equalize across the membrane. Osmosis is the diffusion of water molecules across a selectively permeable membrane.

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

Which of the following statements correctly describe(s) the driving forces for diffusion of Na+ and K+ ions through their respective channels? Select all that apply.

The diffusion of Na+ ions into the cell is facilitated by the Na+ concentration gradient across the plasma membrane. The diffusion of K+ ions out of the cell is impeded by the electrical gradient across the plasma membrane. The electrochemical gradient is larger for Na+ than for K+.

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 factors affect the rate of osmotic movement of water?

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

Active and passive transport of solutes across a membrane typically differ in which of the following ways?

Transport proteins provide a hydrophilic route for the solute to cross the membrane.

In facilitated diffusion, what is the role of the transport protein?

Transport proteins provide a hydrophilic route for the solute to cross the membrane.

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? Which of the following molecular movements is due to diffusion or osmosis? Cells of the pancreas secrete insulin into the bloodstream. The sodium-potassium pump pumps three sodium ions out of a neuron for every two potassium ions it pumps in. When a plant cell is placed in concentrated salt water, water moves out of the cell.

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

Drag the terms on the left to complete the sentences on the right.

When molecules move down their concentration gradient, they move from where they are more concentrated to where they are less concentrated. Diffusion across a biological membrane is called passive transport.

Based on Figure 7.18 in your textbook, which of these experimental treatments would increase the rate of sucrose transport into the cell? Based on Figure 7.18 in your textbook, which of these experimental treatments would increase the rate of sucrose transport into the cell? decreasing cytoplasmic pH adding an inhibitor that blocks the regeneration of ATP adding a substance that makes the membrane more permeable to hydrogen ions decreasing extracellular pH decreasing extracellular sucrose concentration

decreasing extracellular pH

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

embedded in a lipid bilayer.

Identify Structure A (branched sequence on an integral protein).

glycoprotein

This cell is in a(n) _____ solution. The figure shows a cell membrane, the extracellular fluid, and the cytoplasm. The concentration of the solute is higher outside the cell. The figure shows 2 states of the cell: when it was just placed in this solute and over the time.

hypertonic There is a greater concentration of solute outside the cell.

You know that this cell is in a(n) _____ solution because it _____. The figure shows a cell in the solution. There are much more particles outside the cell than inside. So water moves in a direction outside the cell. The cell is wrinkled.

hypertonic solution ... lost water

You know that this cell is in a(n) _____ solution because the cell _____. The figure shows a cell membrane, the extracellular fluid, and the cytoplasm. The concentration of solute is higher inside the cell. The figure shows two states of the cell: when it was just placed in this solute and over the time. Over the time the cell increased in size.

hypotonic ... swelled

What name is given to the process by which water crosses a selectively permeable membrane?

osmosis

Facilitated diffusion is a type of _______.

passive transport

Which of the following processes includes all others? Which of the following processes includes all others? passive transport diffusion of a solute across a membrane facilitated diffusion transport of an ion down its electrochemical gradient osmosis

passive transport

Identify Structure D (two rows of molecules with a head and two tails).

phospholipid bilayer of membrane

Structure A is a _____. The figure shows a cell membrane with integral molecule, which consists of two similar parts with specific recess. There are many particles in the extracellular fluid. One of these particles is labeled A.

solute

What is the function of Structure E (cholesterol)?

stabilization of the phospholipids

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

Structure A in the figure is a(n) _____. Molecules of solute, shown in the figure, can pass through a plasma membrane due to the structure A, which is placed on the surface of the membrane. The structure A has two openings - one to the extracellular fluid, another - to the cytoplasm.

transport protein

Structure B is a _____. The figure shows a cell membrane with integral molecule marked B, which consists of two similar parts with specific recess. There are many particles in the extracellular fluid.

transport protein

Which of the following best describes the structure of a biological membrane? a fluid structure in which phospholipids and proteins move freely between sides of the membrane two layers of phospholipids with proteins either crossing the layers or on the surface of the layers two layers of phospholipids (with opposite orientations of the phospholipids in each layer) with each layer covered on the outside with proteins two layers of phospholipids with proteins embedded between the two layers a mixture of covalently linked phospholipids and proteins that determines which solutes can cross the membrane and which cannot

two layers of phospholipids with proteins either crossing the layers or on the surface of the layers