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

Which of the following plant cells would exhibit the most turgor pressure?

A cell placed in a hypotonic solution

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

Which of these can RAPIDLY pass directly through the phospholipids of the plasma membrane, without the help of a transport protein? A. lipid soluble molecule B. water C. glucose D. hydrogen ion

A only

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.

How does cholesterol affect membrane fluidity?

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 diffusion gradient in cell B is steeper

Why is energy required for active transport?

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.

What function do carbohydrates fulfill in the plasma membrane?

Cell-to-cell recognition

Which of the following statements correctly describes some aspect of exocytosis or endocytosis?

Exocytosis and endocytosis change the surface area of the plasma membrane.

Which of the following processes and organelle(s) accounts for the replacement of lipids and proteins lost from the plasma membrane?

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.

Which of the following statements about diffusion is true?

It is a passive process.

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

Membrane carbohydrates function primarily in cell-cell recognition.

Which of the following is a major difference between prokaryotic and eukaryotic cells?

Most prokaryotic cells have no internal membranes; eukaryotic cells do.

Which of the following particles could diffuse easily through a cell membrane?

Oxygen (O2)

Which of the following statements about passive transport is correct?

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 form a selectively permeable structure.

Which of the following cell structures exhibits selective permeability between a cell and its external environment?

Plasma membrane

Which of the following statements is true regarding potential energy?

Potential energy is the energy possessed by matter due to its location or structure.

Which of the following structural arrangements of the components in biological membranes facilitates the cell membrane's property of selective permeability?

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.

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.

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

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+.

If the pores in the selectively permeable membrane became larger, but still not large enough to let the sugar pass through, what would happen during osmosis in the U-shaped tube compared to what is shown in the figure?

The final water levels would be the same as shown in the figure, but the solutions would reach near equal concentrations faster.

Which statements about the fluid mosaic structure of a membrane are correct?

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; Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane.

How do membrane phospholipids interact with water?

The polar heads interact with water; the nonpolar tails do not.

Which of the following statements about osmosis is correct?

The presence of aquaporins (proteins that form water channels in the membrane) speeds up the process of osmosis.

Which of the following statements about a typical plasma membrane is correct?

The two sides of the plasma membrane have different lipid and protein composition.

Which of the following statements about the conditions shown in the U-shaped tube are true?

There is less free water in the right arm of the tube than in the left arm of the tube; Water is tightly clustered around the hydrophilic solute molecules on both sides of the membrane.

Which of the following is correct regarding peripheral proteins?

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.

Which of the following statements describes the role of the transport protein in facilitated diffusion?

Transport proteins allow solutes to move passively down their concentration gradients across the membrane.

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

In this diagram of the plasma membranes of two adjoining cells, identify the protein indicated by the white arrow, including its function.

a receptor protein that binds with a signaling molecule and relays the message into the cell by activating other molecules inside the cell

If the concentration of phosphate in the cytosol is 2.0 mM, and the concentration of phosphate in the surrounding fluid is 0.1 mM, how could the cell increase the concentration of phosphate in the cytosol?

active transport

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

only channels

allow water molecules and small ions to flow quickly across the membrane; provide a continuous path across the membrane

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans?

amphipathic nature

Which of the following molecules is most likely to passively diffuse across the plasma membrane?

carbon dioxide

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

The movement of glucose into a cell against its concentration gradient is most likely to be accomplished by which of the following?

cotransport of the glucose with a proton or sodium ion that was pumped across the membrane using the energy of ATP hydrolysis

Which of the following is least likely to be important in holding the components of a biological membrane together?

covalent interactions between the phospholipid and protein components of the membrane

A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or neither will occur. Solution A: 3.21% (m/v) NaCl Solution B: 1.65% (m/v) glucose Solution C: distilled H2O Solution D: 6.97% (m/v) glucose Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl

crenation: A, D, E hemolysis: B, C

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?

endocytosis

During osmosis, water diffuses across a selectively permeable membrane from the region of higher ---- concentration and lower ---- concentration to the side with lower ---- concentration and higher ---- concentration.

free water; solute; free water; solute

identify structure A

glycoprotein

This cell is in a(n) _____ solution.

hypertonic

You know that this cell is in a(n) _____ solution because it _____.

hypertonic solution; lost water

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?

hypotonic

You know that this cell is in a(n) _____ solution because the cell _____.

hypotonic; swelled

Endocytosis moves materials _____ a cell via _____.

into; membranous vesicles

All cells have voltages across their membranes. This voltage is called a(n) __________ and is often maintained by __________.

membrane potential; electrogenic pumps

Hydrophobic substances like salad oil are

nonpolar molecules that do not have an affinity for water molecules.

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

osmosis

Facilitated diffusion is a type of _______.

passive transport

A white blood cell engulfing a bacterium is an example of _____.

phagocytosis

identify structure D

phospholipid bilayer of membrane

Which of the following molecules are most abundant in the plasma membrane?

phospholipids

both channels and carriers

provide a hydrophilic path across the membrane; are integral membrane proteins; transport solutes down a concentration or electrochemical gradient

Structure A is a _____. Structure B is a _____.

solute; transport protein

What is the function of Structure E?

stabilization of the phospholipids

You can recognize the process of pinocytosis when _____.

the cell is engulfing extracellular fluid

The plasma membrane exhibits selective permeability. This means that __________.

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

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

A cell is placed into a solution and the cell shrinks. Which of the following is true regarding the solution?

the solution is hypertonic

The permeability of a biological membrane to a specific polar solute may depend on which of the following?

the types of transport proteins in the membrane

If more sugar were added to the solution on the left side of the tube, what would happen to the water level on the right side of the tube?

the water level would go down

Structure A in the figure is a(n) _____.

transport protein

The sodium-potassium pump __________.

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

True or false? Osmosis is a type of diffusion.

true

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.

true

Which of the following best describes the structure of a biological membrane?

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

only carriers

undergo a change in shape to transport solutes across the membrane; transport primarily small polar organic molecules

Which of the following molecules can cross the lipid bilayer of a membrane directly, without a transport protein or other mechanism?

water, carbon dioxide, oxygen, lipids

A semipermeable membrane is placed between the following solutions. Which solution will decrease in volume? Solution A: 1.4% (m/v) starch Solution B: 7.62% (m/v) starch

Solution A: 1.4% (m/v) starch

A semipermeable membrane is placed between the following solutions. Which solution will increase in volume? Solution C: 9% (m/v) NaCl Solution D: 12.4% (m/v) NaCl

Solution D: 12.4% (m/v) NaCl