Deck 4: Membrane Structure and Function

Question 1

Our body recognizes the foreign nature of a parasite or disease agent and we soon build up antibodies. A few parasites can change their identity to evade our immune system. How could cells do this on a regular basis?

A) Replace the cholesterol within the membrane with host cholesterol.
B) Wait for the evolution of new protein membrane molecules.
C) Because the membrane is "set," a cell must reproduce and then the cell with the old membrane must die.
D) A whole new phospholipid bilayer is generated to replace the old layer.
E) New glycoproteins, similar to those found on the host cells, are produced in the cell and moved into the plasma membrane.

Answer 1

E

Question 2

Which type of membrane protein will bind to hormones?

A) channel proteins
B) carrier proteins
C) cell recognition proteins
D) receptor proteins
E) enzymatic proteins

Answer 2

D

Question 3

In certain cancerous cells, the cell divides continuously even in the absence of a growth factor (signaling molecule) that indicates the cell should divide. Which of the following could explain this?

A) a receptor molecule that is always turned on
B) a receptor molecule that is always turned off
C) a transduction pathway that is always turned off
D) a target protein that is always deactivated
E) a gene for cell division that is not expressed when it should be

Answer 3

A

Question 4

Which of the following statements is true regarding the inside and outside of the plasma membrane?

A) Both the inside and outside of the phospholipid bilayer are identical.
B) There are phospholipids on both sides of the membrane, but cytoskeletal filaments are present on the outside and carbohydrates and glycolipids are present on the inside.
C) There are phospholipids on both sides of the membrane, but cytoskeletal filaments are present on the inside and carbohydrates and glycolipids are present on the outside.
D) The inside consists of a phospholipid bilayer while the outside consists of a layer of carbohydrates and glycolipids.
E) The outside consists of a phospholipid bilayer while the inside consists of a layer of proteins.

Question 5

The plasma membrane is composed primarily of

A) proteins and microtubules.
B) lipids and actin filaments.
C) lipids and microtubules.
D) lipids and proteins.
E) proteins and carbohydrates.

Question 6

Proteins do not pass through cell membranes because

A) the membrane is made of protein.
B) they contain nitrogen.
C) they are very large molecules.
D) they cause emulsification.
E) they cause digestion of the cell.

Question 7

According to the fluid-mosaic model of membrane structure

A) proteins make up the bulk of the membrane.
B) only lipids are found in the membrane.
C) cholesterol is the main constituent of the membrane.
D) glycolipids form a mosaic pattern inside the cell.
E) proteins float inside or within the phospholipid bilayer.

Question 8

Blood type is determined by proteins. Blood type A has a different protein than blood type B. Blood type AB has both types of proteins and type O does not have either type of protein. When blood is transfused, the recipient's immune system will detect any new or foreign proteins. The blood type proteins must be located

A) in the red blood cell nucleus.
B) inside the red blood cell cytoplasm.
C) on the outer surface of the red blood cell membrane.
D) in the nuclear membrane.
E) in the endoplasmic reticulum of the red blood cells.

Question 9

In the new procedures developed to clone a mammalian cell, the nucleus is removed from an egg cell and the nucleus from the adult to be cloned is injected inside this cell. If we did this process with a basketball, we would permanently damage the shell. What property of the cell repairs this damage?

A) diffusion of cell membrane proteins
B) carrier proteins restore the membrane lipids
C) isotonic solutions
D) outer and inner sides of the plasma membrane have identical carbohydrate chains
E) the fluid-mosaic nature of the membrane

Question 10

Which of the following molecules add stiffness and strength to the plasma membrane?

A) glycoproteins
B) cholesterol
C) phospholipids
D) enzymatic proteins
E) phosphate groups

Question 11

Which components of a cell membrane are used for cell-to-cell recognition?

A) phospholipids
B) channel proteins
C) glycolipids
D) glycoproteins
E) cholesterol molecules

Question 12

Radioactive isotopes are used to tag proteins in the cell membranes of mouse cells. These cells are then fused with human cells in cultures. What is the likely outcome of the tagged mouse proteins?

A) The tagged proteins remain in the mouse cells and keep their position on the membrane.
B) The tagged proteins remain in mouse cells but move anywhere across the mouse cell membrane.
C) The tagged proteins drift across cell membranes and are soon found dispersed across both human and mouse cell membranes.
D) None of the answer choices will occur since mouse cell membranes are unlike human cell membranes.
E) None of the answer choices will occur since radioactive cells will soon die.

Question 13

What property of phospholipids makes them suitable for the formation of the double layer found in membranes?

A) They are uncharged.
B) They can interact with proteins.
C) They are composed of fatty acids.
D) They have both a hydrophobic and a hydrophilic end.
E) Both ends are hydrophilic.

Question 14

Which of the following are functions of the plasma membrane? Select all that apply.

A) It separates the internal environment of the cell from the external environment.
B) It regulates the entrance and exit of molecules to and from the cell.
C) It helps the cell and the organism maintain a steady internal environment.
D) It serves as a site for protein synthesis.
E) It serves as the site for photosynthesis in plant cells.

Question 15

Certain individuals with a Y chromosome develop into females because testosterone is unable to induce the formation of male sexual characteristics. This is most likely due to a defect in

A) the signaling molecule.
B) the receptor.
C) the transduction pathway.
D) the target protein.
E) the Y chromosome.

Question 16

The same signaling molecule that binds to the receptor on the outside of the cell is used to alter gene expression in the nucleus.

Question 17

Which is a correct association of protein types?

A) carrier proteins-provide a channel for substances to move across a membrane
B) cell recognition proteins-allow a specific molecule to bind to it and may cause a cell response
C) channel proteins-combine with a substance to help it move across a membrane
D) receptor proteins-variations in these proteins cause tissue transplant rejection
E) enzymatic proteins-carry out metabolic reactions directly

Question 18

A student sitting in the back row opened a bottle of foul-smelling perfume and dabbed it on her wrists. One by one (beginning from the back of the room), the students began to cough due to the foul smell. This phenomenon was due to

A) osmosis.
B) molecules moving from an area of low concentration to high concentration.
C) an allergic reaction.
D) diffusion.
E) active transport.

Question 19

Which statement is true concerning movement of molecules across the cell membrane?

A) Water and gas molecules cannot easily pass through the membrane.
B) Small uncharged molecules do not pass through easily.
C) Large molecules pass through easily.
D) Charged molecules pass through easily.
E) Lipid molecules pass through easily.

Question 20

Permeability refers to

A) the movement of molecules from an area of greater concentration to an area of lesser concentration.
B) the extent to which a membrane allows a substance to pass through.
C) the amount of solute in a solution.
D) the state of being permanent.
E) the ability to establish a permanent solute level in a solution.

Question 21

If you have a 10% sugar solution and a 35% sugar solution, the 10% solution is ________ compared to the 35% solution.

A) isotonic
B) sweeter
C) osmotic
D) hypotonic
E) hypertonic

Question 22

Of the following conditions, which is absolutely necessary for diffusion to take place?

A) a differentially permeable membrane
B) low temperatures
C) a concentration difference
D) a non-permeable membrane
E) a living cell

Question 23

Osmosis can occur when a membrane is

A) impermeable.
B) selectively permeable.
C) permeable.
D) plasmolyzed.
E) absent.

Question 24

When water enters a plant cell

A) it bursts.
B) the central vacuole becomes enlarged.
C) the central vacuole shrinks.
D) it undergoes plasmolysis.
E) it undergoes crenation.

Question 25

The pressure that is generated when water flows through a differentially permeable membrane is termed

A) osmotic pressure.
B) turgor pressure.
C) plasmolysis.
D) crenation.
E) tonicity.

Question 26

If we inspect most cell membranes in a living human body, we would find a nearly continuous flow of substances back and forth across the plasma membrane. Which of the following explains this continuous flow?

A) Cell metabolism is constantly using up oxygen and raw materials; this lowers their concentration, so more will diffuse into the cell.
B) Cell metabolism is constantly producing waste molecules; this increases their concentration, so more will diffuse into the cell.
C) Cells produce useful secretions; this increases their concentration, and more will diffuse into the cell.
D) Cell metabolism constantly produces oxygen in respiration; this increases the cell's affinity for carbon dioxide which diffuses into the cell.
E) Cells are non-living and therefore anything can pass in and out of the cell.

Question 27

An isotonic solution means that the solute concentration outside the cell

A) is greater than inside the cell.
B) is less than inside the cell.
C) is the same as inside the cell.
D) has no effect on the cell.
E) is greater than outside the cell.

Question 28

The definition of osmosis is the

A) the movement of solute molecules from a higher concentration to a lower concentration.
B) diffusion of water across a selectively permeable membrane.
C) likelihood that water will diffuse in a particular direction.
D) lower concentration of a solute in a solution.
E) movement of water toward a low solute concentration.

Question 29

Kidney dialysis relies on diffusion of various dissolved waste molecules (solutes) across a non-living semipermeable membrane. If the concentration of solutes in the blood increases over time before dialysis is administered, what will happen to the rate of dialysis when it occurs?

A) It will remain the same since there are no carrier molecules in a non-living membrane.
B) The rate will slow down since the solute is more viscous.
C) The rate will speed up since the concentration gradient is higher.
D) It will remain the same since there is no active transport in a non-living membrane.
E) The rate will depend on the amount of time given for diffusion to take place.

Question 30

When a plant cell is placed in a hypotonic solution, the cell wall prevents

A) diffusion.
B) active transport.
C) the cell from bursting.
D) the cell from shrinking.
E) water from entering the cell.

Question 31

Oxygen diffuses into the capillaries of the lungs because there is

A) a higher concentration of O₂ in the alveoli than the capillaries.
B) a higher concentration of O₂ in the capillaries than the alveoli.
C) a higher concentration of CO₂ in the alveoli than the capillaries.
D) a higher concentration of CO₂ in the capillaries than the alveoli.
E) an equal concentration of O₂ in the alveoli and the capillaries.

Question 32

If 0.9% NaCl were isotonic to a cell, then

A) the cell would burst in a 0.9% solution.
B) the cell would shrink in a 0.9% solution.
C) 1.0% would be hypertonic to the cell.
D) 1.0% would be hypotonic to the cell.
E) The cell would shrink in a 0.1% solution.

Question 33

Once a solute and a solvent are evenly distributed in a solution, they will

A) stop moving about.
B) move back toward a concentration of the solvent.
C) continue to move about but with no net gain in any direction.
D) be out of equilibrium.
E) move from a liquid to gaseous solution.

Question 34

Which is a correct example of tonicity?

A) Distilled water is hypertonic to red blood cells.
B) Turgor pressure is created when a plant cell swells in a hypotonic solution.
C) Plasmolysis results from plant cells in hypotonic solutions.
D) Crenated red blood cells result when they are placed in a hypotonic solution.
E) If a cell is placed in a hypertonic solution, water enters the cell.

Question 35

When you add sugar to your coffee or tea, the sugar is the

A) permeable.
B) solvent.
C) gradient.
D) solution.
E) solute.

Question 36

What will happen to dye crystals if placed in the bottom of a beaker of water?

A) They will undergo osmosis to a different location.
B) They will undergo active transport to a different location.
C) They will all diffuse to the top of the beaker.
D) They will diffuse equally throughout the beaker.
E) They will stay at the bottom of the beaker.

Question 37

A cell placed in a hypotonic solution will

A) lose water.
B) gain water.
C) neither gain nor lose water.
D) lose water initially and then gain water.
E) gain water initially and then lose water.

Question 38

When you cut into most active plant tissue, water appears almost immediately because plant cells contain

A) a hypertonic solution that produces turgor pressure.
B) a hypotonic solution that produces turgor pressure.
C) an isotonic condition and you cut the cell open.
D) a hypertonic condition and cutting it reversed this to hypotonic.
E) a hypotonic condition and cutting it reversed this to hypertonic.

Question 39

The term hypertonic means

A) to lose water.
B) to gain water.
C) a higher solute concentration.
D) a lower solute concentration.
E) an equal solute concentration.

Question 40

A semipermeable membrane sac filled with water and large molecules of starch is suspended in a beaker of distilled water. What will happen?

A) The starch will leave and the water will enter until both sides reach equal concentrations.
B) Water will enter the sac and it will swell.
C) Because the starch cannot leave, the water cannot enter.
D) We cannot determine the outcome unless we know the tonicity of the solutions.
E) The starch will leave the sac and it will shrink.

Question 41

Which is true of facilitated transport by carrier proteins?

A) Facilitated transport only applies to small, lipid-soluble molecules.
B) It is represented by the glucose carrier that can transport hundreds of molecules a second.
C) After a carrier has transported a molecule, it is unable to transport any more.
D) Facilitated transport requires expenditure of chemical energy and is therefore active transport.
E) One carrier protein can carry a variety of different molecules.

Question 42

How can marine animals such as sharks live in salt water?

A) They increase or decrease the amount of urea in their blood until the blood is isotonic with the environment.
B) They increase the amount of urea in their blood until the blood is hypertonic with the environment.
C) They decrease the amount of urea in their blood until the blood is hypotonic with the environment.
D) They contain impermeable membranes which do not allow the salt water to cross into their cells.
E) They block the movement of salt into their cells and maintain a constant blood salt concentration.

Question 43

A cell is placed in a solution of large carbohydrate molecules tagged with a red dye. Soon the cell is dark red, showing a concentration of the nutrient much higher than the external solution. We add a reagent that blocks the use of ATP. What result would you expect from this experiment?

A) The nutrient would continue to rapidly enter the cell by diffusion because as a nutrient it is constantly being used in cell metabolism, so the cell will become more red.
B) The color will remain the same since all future transfer will stop.
C) The color will fade as the import of the nutrient stops and diffusion evens the concentrations as it moves the nutrient molecules out of the cell.
D) The cell will continue to get darker since the import of the nutrient does not involve ATP.
E) The cell will die without access to ATP.

Question 44

Molecules such as glucose and amino acids are not lipid soluble and therefore they

A) easily pass across the cell membrane.
B) require active transport to cross the cell membrane.
C) must be converted to lipids before they can enter a cell.
D) combine with carrier proteins and pass across the cell membrane by facilitated transport.
E) must be engulfed by a cell using endocytosis.

Question 45

Which membrane transport process can continue whether the cell is alive or dead?

A) sodium/potassium pump
B) pinocytosis
C) phagocytosis
D) exocytosis
E) diffusion

Question 46

Which of the following refers to materials only leaving the cell?

A) diffusion
B) exocytosis
C) endocytosis
D) pinocytosis
E) phagocytosis

Question 47

If a cell lacks ATP, which of the following processes would cease to operate immediately?

A) diffusion
B) sodium/potassium pump
C) facilitated diffusion
D) osmosis
E) tonicity

Question 48

In the emergency room, saline solutions are often run into a person's vein. The saline solution must be

A) 0.1% NaCl.
B) 0.5% NaCl.
C) 0.75% NaCl.
D) 0.9% NaCl.
E) 9.0% NaCl.

Question 49

Dead plants seen alongside a salted roadway died because the salt solution caused the cells to

A) undergo crenation.
B) undergo lysis.
C) undergo hemolysis.
D) undergo plasmolysis.
E) not have an effect on the plants.

Question 50

When an intestinal cell ingests substances inside very small vesicles that can only be seen with an electron microscope, this is

A) pinocytosis.
B) phagocytosis.
C) exocytosis.
D) active transport.
E) diffusion.

Question 51

Two solutions are separated by a selectively permeable membrane. On side A, there is a solution composed of 20% protein and 80% water. On side B, the solution is 100% water. As osmosis occurs, what will happen to the solution on side A?

A) It will become less concentrated since protein will move from A to B.
B) It will become more concentrated since water passes from B to A.
C) It will become more concentrated since water passes from A to B.
D) It will become less concentrated since water passes from B to A.
E) It will become more concentrated since protein will move from B to A.

Question 52

In the Malpighian tubules of an insect (blind, threadlike excretory tubule attached to the gut of an insect), salt molecules are actively transferred from body fluids to the inside of the tubule. This transfer of salt molecules would result in

A) water being "pulled" by osmosis into the Malpighian tubule.
B) an increase in the salt concentration of the body fluids.
C) an increase in the water concentration of the body fluids.
D) the Malpighian tubules becoming isotonic to the body fluids.
E) the tubules becoming hypotonic to the body fluids.

Question 53

Two solutions are separated by a selectively permeable membrane. On side A, there is a solution composed of 20% protein and 80% water. On side B, the solution is 100% water. Initially, the solution on side B is ________ to the solution on side A.

A) hypotonic
B) hypertonic
C) isotonic

Question 54

Receptor-mediated endocytosis

A) involves receptor proteins binding to specific molecules.
B) protein pumps moving substances from low concentration to high concentration.
C) protein pumps moving substances from high concentration to low concentration.
D) the cell engulfing large particles.
E) secretion of materials from a cell.

Question 55

Macrophages, a type of white blood cells, are able to remove bacteria from our bloodstream and tissues by

A) passive transport.
B) facilitated diffusion.
C) osmosis.
D) pinocytosis.
E) phagocytosis.

Question 56

When a substance moves from an area of low concentration to an area of high concentration while using energy, the process is termed

A) diffusion.
B) osmosis.
C) facilitated diffusion.
D) pinocytosis.
E) active transport.

Question 57

If a selectively permeable membrane separates a molasses solution from distilled water, over time the

A) molasses will be found in the water.
B) molasses will become more dilute.
C) molasses solution will become more concentrated.
D) molasses will be found in water and it will be more concentrated.
E) solutions will remain the same.

Question 58

The number of mitochondria in a cell would be a general indicator of the extent of

A) diffusion.
B) facilitated transport.
C) active transport.
D) osmosis.
E) both osmosis and diffusion.

Question 59

Active transport

A) moves molecules or ions along their concentration gradient.
B) involves carbohydrate pumps.
C) is associated with large numbers of mitochondria.
D) is associated with fat and skin cells.
E) cannot be done by animal cells.

Question 60

Carrier molecules are required for

A) osmosis.
B) both osmosis AND diffusion.
C) facilitated diffusion.
D) active transport.
E) both facilitated diffusion AND active transport.

Question 61

Oxygen leaves the alveoli in the lungs and enters the capillaries by endocytosis.

Question 62

If a molecule crosses a plasma membrane faster than it diffuses in water, then the process is likely to involve active transport.

Question 63

Compare and contrast exocytosis and endocytosis.

Question 64

Which cell junctions are commonly found in areas that are subject to stretching, such as the skin?

A) adhesion junctions
B) gap junctions
C) tight junctions
D) plasmodesmata
E) None of the answer choices is found between skin cells.

Question 65

Which intercellular junction allows for the rapid movement of small molecules or ions to flow from one animal cell to the next?

A) gap junctions
B) tight junctions
C) adhesion junctions
D) desmosomes
E) plasmodesmata

Question 66

If the proteins forming the cell junctions within the stomach were denatured, what is a likely consequence?

A) The desmosome junctions would not hold together, causing the cells in the stomach to pull apart.
B) The tight junctions would not hold together, causing the cells in the stomach to pull apart.
C) The desmosome junctions would be bonded together more tightly, causing the cells in the stomach to form a solid barrier.
D) The gap junctions would not hold together, causing the cells in the stomach to be unable to pass ions back and forth.
E) The desmosome junctions would not hold together, causing the cells in the kidney to pull apart.

Question 67

Which of the following factors could cause the cell membrane to become less permeable?

A) if the channel proteins were to denature and become inactive
B) if the molecules trying to enter the cell were decreased in size
C) if the hydrophilic head of the phospholipids were to become hydrophobic while the hydrophobic tails become hydrophilic
D) if the size of the protein channel was to increase
E) All of the answer choices would cause the cell membrane to become less permeable.

Question 68

Which component of the extracellular matrix is responsible for forming proteoglycans?

A) amino sugars
B) fibronectin
C) collagen
D) elastin
E) integrin

Question 69

Explain the difference between peripheral proteins and integral proteins as they relate to the cell membrane.

Question 70

If a particular molecule is brought into the cell by receptor-medicated endocytosis, then changing the receptors will change the molecule that is being transported.

Question 71

One way to determine whether something is being actively transported across a membrane is to compare its rate of transport with and without a chemical that blocks ATP production.

Question 72

Exocytosis is carried out by proteins in the cell membrane.

Question 73

What two components are commonly found in the extracellular matrix that help resist stretching and provide resilience?

A) proteins and polysaccharides
B) proteins and phospholipids
C) polysaccharides and phospholipids
D) amino acids and phospholipids
E) nucleic acids and proteins

Question 74

The extracellular matrix is responsible for which of the following features?

A) The extracellular matrix helps the cell resist stretching.
B) The extracellular matrix enables the cell to adhere to neighboring cells.
C) The extracellular matrix plays a role in cell signaling.
D) The extracellular matrix acts as a structural feature.
E) All of the answer choices are correct.

Question 75

List the three types of intercellular junctions found in animal cells and indicate their function.