Deck 5: Membrane Structure and Function

Question 1

Some parasites and disease agents regularly change their identity before our immune system can build up substantial antibodies. How could cells change their chemical identity on a regular basis?

A) Rapid evolution produces mutations.
B) A new phospholipid bilayer is generated to replace the old layer.
C) Because the membrane is "set," the cell must reproduce and then the cell with the old membrane must die.
D) Cells eliminate all surface proteins and present only a naked lipid bilayer.
E) Different glycolipids and glycoproteins are produced internally and moved into the plasma membrane.

Answer 1

E

Question 2

Which statement is true about the plasma membrane?

A) The proteins make up the matrix of the membrane.
B) The model can be likened to a sandwich where phospholipids are like the bread and proteins are like the filling.
C) The fluid nature of the membrane is regulated by flip-flopping of the phospholipids from one side of the membrane to the other.
D) Proteins and phospholipids can move sideways within the plane of the membrane.

Answer 2

D

Question 3

Which of the following protein functions is not correctly associated with the correct integral protein?

A) carrier proteins-facilitate passage of molecules through the membrane
B) enzymatic proteins-catalyze a specific reaction
C) channel proteins-block the activity of carrier proteins
D) cell recognition proteins-recognize pathogens

Answer 3

C

Question 4

Which of the following is NOT associated with animal cells?

A) an extracellular matrix
B) plasmodesmata
C) gap junctions
D) adhesion junctions (desmosomes)
E) tight junctions

Question 5

Having similar ____________ would allow tissues and organs to be transplanted easily.

A) cell recognition proteins
B) major histocompatibility complex proteins
C) carbohydrate chains in the cell membrane
D) all of the choices are involved in tissue transplantation

Question 6

The major functions of the plasma membrane do NOT include

A) separation of the fluid environments inside and outside the cell.
B) regulation of molecules and ions that pass into and out of the cell.
C) recognition and communication between different cells and tissues.
D) maintaining connections between adjacent cells.
E) production of proteins used in construction of the cell wall.

Question 7

Which statement is NOT true about the proteins in the plasma membrane?

A) Proteins may be attached to the inner surface of the plasma membrane.
B) The hydrophobic portion of a protein is embedded within the membrane.
C) Some peripheral proteins are connected to cytoskeletal filaments.
D) Integral proteins are responsible for membrane functions.
E) Glycoproteins contain carbohydrate chains that are oriented toward the inner surface of the membrane.

Question 8

Which type of molecule will require some amount of energy to cross the cell membrane?

A) glycerol
B) polar
C) non-polar molecules
D) carbon dioxide
E) oxygen

Question 9

Which of the following is true with respect to plant cell walls?

A) They contain n-acetylglutamic acid.
B) They all have secondary cell walls to some extent.
C) There is a greater amount of cellulose in secondary cell walls than in primary cell walls.
D) Lignin is found in primary cell walls of plants.

Question 10

The channel protein that accounts for why water can cross a membrane more quickly than expected is

A) ATP synthetase.
B) aquaporin.
C) the sodium-potassium pump.
D) integrin.

Question 11

Which is the best definition of osmosis?

A) The movement of molecules from an area of their higher concentration to an area of their lower concentration.
B) The movement of water across a semi permeable membrane from an area of higher water concentration to an area of lower water concentration.
C) The movement of molecules from an area of their lower concentration to an area of their higher concentration.
D) The movement of water across a semi permeable membrane from an area of lower water concentration to an area of higher water concentration.
E) The movement of a substance against its concentration gradient through the release of energy from ATP.

Question 12

Whether a molecule can cross the plasma membrane depends upon

A) the size of the molecule.
B) the shape of the molecule.
C) the chemical properties of the molecule.
D) the charge of the molecule.
E) All of the choices are correct.

Question 13

Proteins in a membrane are

A) peripheral if they are on the inside surface held in place by the cytoskeleton.
B) integral if they are embedded in the membrane and protrude from both surfaces of the bilayer.
C) integral if they protrude from only one surface of the bilayer.
D) All of the choices are correct.

Question 14

In a phospholipid bilayer, the

A) phosphate groups are hydrophobic.
B) fatty acid tails are ionized.
C) fatty acid tails are hydrophilic.
D) proteins are located only between the two layers.
E) phosphate heads are oriented toward the exterior of the cell or toward the cytoplasm.

Question 15

Red blood cells come in many "blood types" including type A, type B, type AB, type O [lacking proteins A and B], Rh positive, and Rh negative [lacking Rh⁺] and many others. If blood is transfused, the recipient detects any new or "foreign" proteins. These blood type proteins are

A) in the plasma where they have been secreted by the red blood cells.
B) inside the red blood cell cytoplasm.
C) on the outer surface of the red blood cell membrane.
D) evenly distributed throughout the cell contents and plasma.
E) in the red blood cell nucleus.

Question 16

Active transport

A) requires an input of ATP.
B) is involved in diffusion.
C) occurs in osmosis and facilitated transport.
D) All of the choices are correct.

Question 17

Freshwater protozoans react to a/an _____ environment by removing water through _____.

A) hypertonic, turgor pressure
B) hypotonic, turgor pressure
C) isotonic, a contractile vacuole
D) hypertonic, a contractile vacuole
E) hypotonic, a contractile vacuole

Question 18

Which phrase does NOT describe one of the functions of proteins of the plasma membrane?

A) forming a channel through the membrane
B) initiating the replication of the genetic material
C) binding to a substance to carry it through the membrane
D) acting as a receptor for substances external to the cell
E) increasing the rate of a chemical reaction

Question 19

If a cell is placed in a hypotonic solution, which will occur?

A) Salts will move into the cell from the surrounding solution.
B) Water will move into the cell from the surrounding solution.
C) Salts will move out of the cell into the surrounding solution.
D) Water will move out of the cell into the surrounding solution.
E) None of the choices will occur.

Question 20

A major chemical that regulates the fluidity of animal cell membranes by stiffening the membrane at higher temperatures and preventing the membrane from freezing at lower temperature is

A) cholesterol.
B) lipid in nature.
C) a steroid.
D) All of the choices are correct.

Question 21

Is this cell an animal or plant cell? In what type of environment is this cell found? Is there a net movement of water into or out of the cell? Explain your answer.

Question 22

Design an experiment that illustrates how any one of these factors (temperature, pressure, molecule size) may affect the rate of diffusion.

Question 23

Why do membranes self-assemble into their characteristic phospholipids bilayer?

Question 24

Imagine a person has a genetic disorder that prevents them from producing the protein collagen, what types of cellular issues will they be faced with?

A) The cell will not have the ability to divide properly.
B) The cell will not have the ability to regulate the movement of molecules through the membrane.
C) The cell would not be recognized by the body's immune system.
D) The cell would not have the ability to resist stretching.
E) All of the choices are plausible.

Question 25

Sugars and amino acids are carried into the cell by means of

A) facilitated transport.
B) diffusion.
C) endocytosis.
D) exocytosis.

Question 26

The process by which cholesterol is transported into the cell by the binding of LDL to its receptor and the internalization of the receptor-LDL complex is

A) facilitated transport.
B) active transport.
C) cotransport.
D) endocytosis.
E) exocytosis.

Question 27

In the cell pictured, there is no net movement of water. The amount leaving the cell and entering the cell is the same. In what type of environment is this cell found?

A) hypertonic
B) hypotonic
C) isotonic
D) none of the above

Question 28

A crystal of green dye is added to a beaker of water. The dye will undergo diffusion. After studying the series of beakers from the left to the right, define diffusion and state the ultimate outcome of diffusion?

Question 29

Study the series of pictures to identify the process as

A) facilitated transport.
B) active transport.
C) passive transport.
D) osmosis.

Question 30

A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. There is a differentially permeable membrane across the broad end of the tube, which is permeable to water but not to the sugar glucose. What will occur over time to the water? To the solute?

Question 31

Which is the best definition of active transport?

A) movement of molecules from an area of their higher concentration to an area of their lower concentration
B) movement of water across a semi permeable membrane from an area of higher water concentration to an area of lower water concentration
C) movement of molecules from an area of their lower concentration to an area of their higher concentration
D) movement of water across a semi permeable membrane from an area of lower water concentration to an area of higher water concentration
E) movement of a substance against its concentration through the release of energy from ATP

Question 32

A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. The solution in the thistle tube is _______ to the solution in the beaker.

A) hypertonic
B) hypotonic
C) isotonic
D) none of the answer choices

Question 33

Study the series of pictures to identify the process through which materials are being transported across the membrane. Explain how you arrived at your answer.

Question 34

Eukaryotic cells are substantially larger than bacterial cells and average over 20 times more volume-per-surface-area than bacterial cells. How can the eukaryotic cell membrane provide this higher rate of exchange of materials?

A) Plasma membrane folds increase the surface area.
B) Carrier proteins speed the rate at which a solute crosses the plasma membrane in the direction of decreasing concentration.
C) Mitochondria are concentrated near membranes to provide energy for active transport of molecules or ions.
D) Large molecules are engulfed by vesicle formation.
E) All of the choices are correct.

Question 35

Plants show turgor pressure when

A) cells are losing water from their water vacuoles.
B) cells contain water vacuoles that are full of water.
C) water is being used up in photosynthesis.
D) water is being evaporated from the leaves.

Question 36

A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. Where is the highest concentration of water found?

A) in the 10% solution
B) in the 5% solution
C) the concentration of water is the same in both solutions.
D) None of the answer choices

Question 37

Why does this model of a phospholipids bilayer in Fig. 1 not 'work'?

Question 38

Before boarding an airplane on a commercial flight, the traveler must show personal identification and a ticket to airport security. The traveler must then remove his shoes and place any carry-on items on the belt of an x-ray machine before walking through the checkpoint. How is the passage of molecules through a membrane similar to travelers passing through airport security?

Question 39

A 10% glucose solution is placed in the thistle tube. The thistle tube is placed in a beaker that contains a 5% glucose solution. There is a differentially permeable membrane across the broad end of the tube, which is permeable to water but not to the sugar glucose. As diffusion occurs

A) the 10% solution will become more concentrated and the 5% solution will become less concentrated.
B) both solutions will become more concentrated.
C) the 10% solution will become less concentrated and the 5% solution will become more concentrated.
D) both solutions will become less concentrated.

Question 40

Why does this model of a phospholipids bilayer in Fig. 2 not 'work'?

Question 41

Which scenario is most likely to occur if the mitochondria in the kidney cells were to decrease in function?

A) The kidneys would improve in function.
B) The kidneys would begin excreting large amounts of waste products.
C) The amount of active transport in the kidneys would significantly decrease.
D) The amount of active transport in the kidneys would increase.

Question 42

All life forms currently have a basic cell membrane so we presume that the earliest forms of life had this "fence" isolating the internal organization from the external chaos. It is likely that the primordial environment was acidic. In order for a cell to function in this type of environment, the cell membrane would have to include

A) a sodium (Na⁺) pump.
B) a proton (H⁺) pump.
C) mitochondria underneath in order to provide energy for active transport.
D) an acid-proof cell wall.
E) a totally nonpermeable membrane.

Question 43

What type of transport mechanism is required to move sodium ions against their concentration gradient?

A) active
B) passive
C) diffusion
D) osmosis

Question 44

Why can nonpolar molecules freely cross the cell membrane while polar molecules require energy?

Question 45

Why is the energy expended during endocytosis worth it?

A) The cell increases the amount of ATP produced in order to complete endocytosis.
B) The contents drawn into the cell are isolated from the cytoplasm preventing them from altering the cells function.
C) The cell expends such a small amount of energy to run endocytosis it doesn't really matter.
D) There is no energy expenditure during endocytosis.

Question 46

Which of the following is an example of active transport through a cell membrane?

A) Movement of carbon dioxide out of the blood stream and into the lungs
B) Movement of oxygen from the lungs into the bloodstream
C) Movement of sweat onto the surface of your skin
D) Absorption of glucose from the gut into the bloodstream

Question 47

The process by which a white blood cell or an amoeba engulfs bacteria is called phagocytosis.

Question 48

Which of the following situations is most likely to produce a heart attack?

A) The gap junctions have collapsed and they do not allow the correct flow of ions from one cell to the next.
B) The plasmodesmata have collapsed and they do not allow the correct flow of ions from one cell to the next.
C) The tight junction has ripped and is allowing ions to leak through the membrane lining the heart.
D) The cell walls have broken down and are not able to support the heart.

Question 49

In the cells that line the lumen of the small intestine, gap junctions keep materials from the digestive tract from slipping between the cells and entering the tissues.

Question 50

Which process is responsible for moving cellular wastes across the cell membrane and out of the cell?

A) endocytosis
B) exocytosis
C) pinocytosis
D) receptor-mediated endocytosis

Question 51

Receptor-mediated endocytosis involves the use of specific proteins in the cell membrane.

Question 52

Which type of junctions will create a solid barrier to prevent molecules from moving between the cells?

A) gap
B) desmosomes
C) tight
D) plasmodesmata

Question 53

In the sodium-potassium pump, sodium is transported out of the cell and potassium is transported into the cell as ATP is broken by a membrane protein.

Question 54

Which cell junction is unique to animals? v: 04_12_2014_QC_47498

A) gap
B) tight
C) desmosomes
D) all are unique to animals

Question 55

Which of the following is the reason plants wilt if they are watered with a salt solution?

A) to protect the leaves from full exposure to the salt
B) an increase in turgor pressure
C) salt weakens the plant cell walls
D) loss of water due to the salt solution resulting in a decrease in turgor pressure

Question 56

Fluidity of a membrane increases as the percentage of unsaturated fatty acids in the phospholipids goes up.

Question 57

If a living plant were moved from a freshwater aquarium to a saltwater aquarium, which of the following would occur?

A) Nothing. The plant would be fine in either aquarium.
B) The plant's cells would take on ions.
C) The plant's cells would take on water and will lyse.
D) The plant's cells would lose water and plasmolysis would occur.

Question 58

Which cell junction will allow the movement of molecules between two plant cells?

A) plasmodesmata
B) gap
C) tight
D) adhesion

Question 59

Which type of cellular process will most likely be used by an amoeba in order to obtain food?

A) phagocytosis
B) pinocytosis
C) exocytosis
D) receptor-mediated endocytosis

Question 60

An extracellular matrix helps some cells to adhere to neighboring cells.