Bio Chapter 7
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 0.8M
1.0M
Which of the following plant cells would exhibit the most turgor pressure? A cell placed in an isotonic solution A cell placed in a hypotonic solution A cell placed in a hypertonic 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 A small nonpolar molecule 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 nonpolar molecule, such as a hydrocarbon Water Glucose
A nonpolar molecule, such as a hydrocarbon
Which of the following is a correct difference between active transport and facilitated diffusion? 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.
Active transport requires energy from ATP, and facilitated diffusion does not.
How does cholesterol affect membrane fluidity? At body temperature, it makes the membrane more fluid It has no effect on membrane fluidity At body temperature, it makes the membrane less fluid.
At body temperature, it makes the membrane less fluid.
What function do carbohydrates fulfill in the plasma membrane? Cell-to-cell recognition They facilitate enzymatic processes. They contribute to its selective permeability
Cell-to-cell recognition
Which of the following molecules are most abundant in the plasma membrane? Phospholipids Proteins Water
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 cell will decrease in size as water flows out of it. The solutes will diffuse into the cell. The solutes will diffuse out of the cell
The cell will decrease in size as water flows out of it.
All cells have voltages across their membranes. This voltage is called a(n) __________ and is often maintained by __________. membrane potential; electrogenic pumps concentration gradient; osmosis electrochemical gradient; diffusion
membrane potential; electrogenic pumps
The plasma membrane exhibits selective permeability. This means that __________. the plasma membrane allows any substance to flow through it easily 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 allows some substances to flow through it more easily than others
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 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
B; the diffusion gradient in cell B is steeper
Why is energy required for active transport? Because it moves solutes against their concentration gradient To allow the movement of water from a hypotonic solution to a hypertonic solution To allow the movement of solutes down their concentration gradient To allow the movement of water from a hypotonic solution to a hypertonic solution Because it helps maintain water balance in cells without walls
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? Both cells would lose water; the red blood cell would shrivel, and the plant plasma membrane would pull away from the cell wall. Both cells would gain water by osmosis; the red blood cell would burst, and the plant cell would increase in turgor pressure. 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? Carbon dioxide Glucose DNA
Carbon dioxide
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? Passive transport Endocytosis Osmosis
Endocytosis
Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane? Endocytosis and Golgi Receptor-mediated endocytosis and smooth ER and Golgi Exocytosis and smooth and rough ER
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. Facilitated diffusion of solutes occurs through phospholipid pores in the membrane. Facilitated diffusion requires energy to drive a concentration gradient.
Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.
Which of the following statements describes a characteristic feature of a carrier protein in a plasma membrane? It exhibits specificity for a particular type of molecule. It works against diffusion. It requires the expenditure of cellular energy to function. It has no hydrophobic regions.
It exhibits specificity for a particular type of molecule.
Which of the following statements about diffusion is true? It is a passive process. It requires expenditure of energy by the cell. 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 about diffusion is true? It is an active process in which molecules move from a region of lower concentration to a region of higher concentration. It requires an expenditure of energy by the cell. It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. It is very rapid over long distances.
It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
Which of the following statements concerning carbohydrates associated with the plasma membrane is correct? The carbohydrate composition of most eukaryotic plasma membranes is quite similar. Membrane carbohydrates function primarily in cell-cell recognition. Carbohydrates are only found associated with the membranes of prokaryotic cells. Carbohydrates on the plasma membrane are typically short chains of between two and five monosaccharides.
Membrane carbohydrates function primarily in cell-cell recognition.
Which of the following statements about passive transport is correct? 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 operates independently of diffusion.
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 statements about the role of phospholipids in the structure and function of biological membranes is correct? Phospholipids are completely insoluble in water. Phospholipids form a selectively permeable structure. Phospholipids form a single sheet in water. Phospholipids form a structure in which the hydrophobic portion faces outward. They are triacylglycerols, which are commonly available in foods.
Phospholipids form a selectively permeable structure.
Which of the following cell structures exhibits selective permeability between a cell and its external environment? Plasma membrane Mitochondria Chloroplasts
Plasma membrane
When a plant cell, such as one from a tulip leaf, is submerged in a hypertonic solution, what is likely to occur? Plasmolysis will shrink the interior of the cell. The cell will become flaccid. The cell will burst. The cell will become turgid.
Plasmolysis will shrink the interior of the cell.
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 Proteins embedded in two layers of phospholipids Phospholipids sandwiched between two layers of protein
Proteins embedded in two layers of phospholipids
How does the "fluid mosaic model" describe the structure of the plasma membrane? 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 fluid characteristic is due to the presence of carbohydrates, and the mosaic characteristic is due to the presence of phospholipids. Only the proteins in the membrane contribute to its fluidity.
Proteins in the membrane contribute to the mosaic quality of the membrane while the lateral and rotational movements of phospholipids contribute to its fluidity.
What will happen to a red blood cell (RBC), which has an internal ion content of about 0.9%, if it is placed into a beaker of pure water? The cell will remain the same size because the solution outside the cell is isotonic. The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC. The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC. The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution? The solution is hypotonic. The solution has the same solute concentration as the cell. The solution is hypertonic. The cell is hypertonic None of the listed responses is correct.
The solution is hypertonic.
Which of the following is correct regarding peripheral proteins? These proteins are found only on the surface of the plasma membrane. They span the entire phospholipid bilayer They exhibit only hydrophobic properties. They have no specific function in the plasma membrane. These proteins exhibit both hydrophilic and hydrophobic properties.
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 exhibit only hydrophilic properties. They have no specific function in the plasma membrane.
These proteins exhibit both hydrophilic and hydrophobic properties.
Which of the following molecules dramatically increases the rate of diffusion of water across cell membranes? the sodium-potassium pump ATP gated ion channels aquaporins
aquaporins
According to the fluid mosaic model of cell membranes, phospholipids _____. occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane frequently flip-flop from one side of the membrane to the other have hydrophilic tails in the interior of the membrane can move laterally along the plane of the membrane
can move laterally along the plane of the membrane
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. channel; carrier peripheral; enzymatic active transport; signal transduction
channel; carrier
Several epidemic microbial diseases of earlier centuries incurred high death rates because they resulted in severe dehydration due to vomiting and diarrhea. Today they are usually not fatal because we have developed which of the following types of treatments? antiviral medications that are efficient and work well with most viruses hydrating drinks with high concentrations of salt and glucose intravenous feeding techniques medications to slow blood loss
hydrating drinks with high concentrations of salt and glucose
Which of the following membrane activities requires energy from ATP hydrolysis? movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell facilitated diffusion of chloride ions across the membrane through a chloride channel movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid movement of carbon dioxide out of a paramecium
movement of Na+ ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid
Which of the following types of molecules are hydrophilic and therefore excluded from the hydrophobic portion of the phospholipid bilayer? peripheral membrane proteins integral membrane proteins cholesterol transmembrane proteins
peripheral membrane proteins
White blood cells engulf bacteria using _____. receptor-mediated exocytosis phagocytosis osmosis pinocytosis
phagocytosis
The sodium-potassium pump __________. transports glucose into the cell transports sodium ions out of the cell and transports potassium ions into the cell transports potassium ions into the cell
transports sodium ions out of the cell and transports potassium ions into the cell
