BSC 1010C Ch7 Dynamic Study

The internal solute concentration of a plant cell is about 0.8M. To demonstrate plasmolysis, it would be necessary to suspend the cell in what solution? 1.0M 0.4M distilled water 0.8M 150m

1.0M

Which of the following plant cells would exhibit the most turgor pressure? All of the listed responses are correct. A cell placed in a hypotonic solution A cell placed in a hypertonic solution None of the listed responses is correct. A cell placed in an isotonic solution

A cell placed in a hypotonic solution

Which of the following would be least likely to diffuse through a plasma membrane without the help of a transport protein? A large polar molecule Any of the above would easily diffuse through the membrane. A small nonpolar molecule Dissolved gases such as oxygen or carbon dioxide A large nonpolar molecule

A large polar molecule

Which of the following substances would be most likely to pass through the plasma membrane without the help of a transport protein? A large polar molecule Glucose A negatively charged ion Water A nonpolar molecule, such as a hydrocarbon

A nonpolar molecule, such as a hydrocarbon

Which of the following is a correct difference between active transport and facilitated diffusion? Active transport involves transport proteins, and facilitated diffusion does not. Active transport requires energy from ATP, and facilitated diffusion does not. Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. Active transport can move solutes in either direction across a membrane, but facilitated diffusion can only move in one direction. Facilitated diffusion involves transport proteins, and active transport does not.

Active transport requires energy from ATP, and facilitated diffusion does not.

How does cholesterol affect membrane fluidity? At body temperature, it makes the membrane less fluid. It has no effect on membrane fluidity. It allows phospholipids to pack tightly together. At body temperature, it makes the membrane more fluid. At lower temperatures, it makes the membrane more fluid.

At body temperature, it makes the membrane less fluid.

Cells A and B are the same size, shape, and temperature, but cell A is metabolically less active than cell B; cell B is actively converting oxygen to water in cellular respiration. Oxygen will diffuse more rapidly into cell __________ because __________. B; the oxygen molecules inside cell B have a higher kinetic energy B; the diffusion gradient in cell B is steeper A; its membrane transport proteins will not be saturated B; the gradient of oxygen is oriented in the opposite direction compared to cell A A; the diffusion gradient there is shallower

B; the diffusion gradient in cell B is steeper

Why is energy required for active transport? Because it helps maintain water balance in cells without walls To allow the movement of solutes down their concentration gradient To allow the movement of water from a hypotonic solution to a hypertonic solution To allow the movement of water from a hypotonic solution to a hypertonic solution Because it moves solutes against their concentration gradient

Because it moves solutes against their concentration gradient

If a red blood cell and a plant cell were placed in seawater, what would happen to the two types of cells? Seawater is isotonic to both cells, therefore, neither cell will change as there will be no movement of water into or out of the cells. The red blood cell would shrink, and the plant cell would gain water. Both cells would gain water by osmosis; the red blood cell would burst, and the plant cell would increase in turgor pressure. Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall. The red blood cell would burst, and the plant cell would shrink.

Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall.

Which of the following molecules is most likely to passively diffuse across the plasma membrane? Sodium ion Glucose Carbon dioxide DNA Hemoglobin

Carbon dioxide

What function do carbohydrates fulfill in the plasma membrane? They contribute to its selective permeability. Transport of molecules across the membrane They contribute to its "fluid" characteristic. Cell-to-cell recognition They facilitate enzymatic processes.

Cell-to-cell recognition

A nursing infant is able to obtain disease-fighting antibodies, which are large protein molecules, from its mother's milk. These molecules probably enter the cells lining the baby's digestive tract via which process? Active transport Passive transport Exocytosis Endocytosis Osmosis

Endocytosis

Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane? Receptor-mediated endocytosis and smooth ER and Golgi Endocytosis and Golgi Exocytosis and smooth and rough ER Flip-flop of phospholipids from one side of the plasma membrane to the other and the Golgi Active transport and the rough endoplasmic reticulum

Exocytosis and smooth and rough ER

Which of these statements describes some aspect of facilitated diffusion? Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane. There is only one kind of protein pore for facilitated diffusion. Facilitated diffusion requires energy to drive a concentration gradient. Facilitated diffusion of solutes occurs through phospholipid pores in the membrane. Facilitated diffusion is another name for osmosis.

Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.

Which of the following statements about diffusion is true? It always requires integral proteins of the cell membrane. It is a passive process. It requires expenditure of energy by the cell. It is very rapid over long distances. It occurs when molecules move from a region of lower concentration to a region of higher concentration.

It is a passive process.

Which of the following statements concerning carbohydrates associated with the plasma membrane is correct? Carbohydrates are only found associated with the membranes of prokaryotic cells. Carbohydrates associated with the plasma membrane are located on both surfaces of the membrane. The carbohydrate composition of most eukaryotic plasma membranes is quite similar. Carbohydrates on the plasma membrane are typically short chains of between two and five monosaccharides. Membrane carbohydrates function primarily in cell-cell recognition.

Membrane carbohydrates function primarily in cell-cell recognition.

Which of the following statements about passive transport is correct? Passive transport operates independently of diffusion. Passive transport operates independently of the concentrations of the moving solute. Passive transport permits the solute to move in either direction, but the net movement of the population of solute molecules occurs down the concentration gradient of the molecule. Passive transport does not occur in the human body. In passive transport, solute movement stops when the solute concentration is the same on both sides of the membrane.

Passive transport permits the solute to move in either direction, but the net movement of the population of solute molecules occurs down the concentration gradient of the molecule.

Which of the following molecules are most abundant in the plasma membrane? Phospholipids Cholesterol Carbohydrates Proteins Water

Phospholipids

Which of the following statements about the role of phospholipids in the structure and function of biological membranes is correct? Phospholipids form a selectively permeable structure. Phospholipids are completely insoluble in water. Phospholipids form a single sheet in water. They are triacylglycerols, which are commonly available in foods. Phospholipids form a structure in which the hydrophobic portion faces outward.

Phospholipids form a selectively permeable structure.

Which of the following cell structures exhibits selective permeability between a cell and its external environment? Mitochondria Lysosomes Endoplasmic Plasma membrane Chloroplasts

Plasma membrane

Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability? A layer of protein coating a layer of phospholipid A phospholipid bilayer with proteins scattered on the surfaces of the membranes Phospholipids sandwiched between two layers of protein Proteins embedded in two layers of phospholipids Proteins sandwiched between two layers of phospholipids

Proteins embedded in two layers of phospholipids

Red blood cells contain approximately a 2% concentration of solutes. A red blood cell is placed into a solution that contains a 4% concentration of solutes to which the cell is not permeable. What will happen to the red blood cell? The solutes will diffuse out of the cell. The cell will increase in size as water flows into it. Nothing will happen because the solution and the cell are isotonic to each other. The solutes will diffuse into the cell. The cell will decrease in size as water flows out of it.

The cell will decrease in size as water flows out of it.

A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution? The solution is hypotonic. None of the listed responses is correct. The solution is hypertonic. The solution has the same solute concentration as the cell. The cell is hypertonic.

The solution is hypertonic.

Which of the following is correct regarding peripheral proteins? They exhibit only hydrophobic properties. These proteins exhibit both hydrophilic and hydrophobic properties. They have no specific function in the plasma membrane. These proteins are found only on the surface of the plasma membrane. They span the entire phospholipid bilayer.

These proteins are found only on the surface of the plasma membrane.

Which of the following is correct regarding integral proteins? These proteins exhibit both hydrophilic and hydrophobic properties. They have no specific function in the plasma membrane. They exhibit only hydrophilic properties. These proteins are found only on the surface of the plasma membrane. They exhibit only hydrophobic properties.

These proteins exhibit both hydrophilic and hydrophobic properties.

In facilitated diffusion, __________ proteins provide openings in the plasma membrane for substances to flow through without changing structure, and __________ proteins allow passage of substances through the plasma membrane after undergoing a subtle change in shape. peripheral; enzymatic receptor; channel carrier; channel channel; carrier active transport; signal transduction

channel; carrier

All cells have voltages across their membranes. This voltage is called a(n) __________ and is often maintained by __________. iotonic solution; diffusion concentration gradient; osmosis electrochemical gradient; diffusion membrane potential; electrogenic pumps None of the listed responses is correct.

membrane potential; electrogenic pumps

The plasma membrane exhibits selective permeability. This means that __________. the plasma membrane allows some substances to flow through it more easily than others the structure of the plasma membrane does not affect its permeability the plasma membrane does not allow any substance to flow through it the plasma membrane allows any substance to flow through it easily proteins in the membrane do not affect its permeability

the plasma membrane allows some substances to flow through it more easily than others

How does the "fluid mosaic model" describe the structure of the plasma membrane? None of the listed responses is correct. The fluid characteristic is due to the presence of carbohydrates, and the mosaic characteristic is due to the presence of phospholipids. Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity. Only the proteins in the membrane contribute to its fluidity. The plasma membrane is a rigid structure that exhibits little flexibility.

Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.

The sodium-potassium pump __________. transports potassium ions into the cell transports glucose into the cell transports sodium ions out of the cell transports sodium ions out of the cell and transports potassium ions into the cell does not require energy to function

transports sodium ions out of the cell and transports potassium ions into the cell