Deck 5: Membranes and Transport

Question 1

The selective permeability of a cell membrane is due to ____.

A) the hydrophobic core formed by the phospholipid tails
B) the hydrophilic surface facing the cell's exterior
C) glycolipids on the surface of the membrane
D) the position of cholesterol in the membrane bilayer
E) the hydrophilic core formed by the phospholipid tails

Answer 1

A

Question 2

Organisms must constantly bring in certain molecules and ions while keeping others out. This function is accomplished by ____.

A) the nucleus
B) lysosomes
C) vesicles
D) the plasma membrane
E) the Golgi complex

Answer 2

D

Question 3

The "mosaic" part of the fluid mosaic model refers to the membrane ____.

A) proteins
B) phospholipids
C) cholesterol
D) functions
E) layers

Answer 3

A

Question 4

Which proteins in the plasma membrane identify a cell as part of the same individual or as foreign?

A) transport proteins
B) recognition proteins
C) receptor proteins
D) cell adhesion proteins
E) nuclear proteins

Question 5

Which protein group links cells together by recognizing and binding receptors or chemical groups on other cells or the extracellular matrix?

A) transport proteins
B) recognition proteins
C) receptor proteins
D) cell adhesion proteins
E) nuclear proteins

Question 6

According to the fluid mosaic model of cell membranes, the fluid part of the model refers to ____.

A) the constant movement of the hydrophilic tails in the interior of the membrane
B) a thin layer of water found sandwiched between the two layers of phospholipids
C) the phospholipid molecules that vibrate, spin, and exchange places within the same layer of the bilayer
D) the free movement of cholesterol molecules within the membrane
E) the frequent flip-flop of phospholipids from one side of the membrane to the other

Question 7

The major structural components of a cell membrane are ____.

A) phospholipids and cellulose
B) phospholipids, protein, and sterols
C) protein and sterols
D) glycolipids and proteins
E) phospholipids and glycolipids

Question 8

As part of an experiment, researchers grew several different types of cells in the presence of radioactive iodine. After some time had passed, the cells were washed, and the levels of iodine inside the cell were determined. What is the most plausible explanation for why some cells had higher levels of radioactivity after treatment than others?

A) Cells that had high radioactivity levels after treatment contain iodine transporters.
B) Cells that had high radioactivity levels after treatment lack iodine transporters.
C) Cells that had high radioactivity levels after treatment had a mutation in genes encoding iodine transporter proteins.
D) Cells that had high radioactivity levels after treatment lack clathrin.
E) Cells that had high radioactivity levels after treatment lack lysosomes.

Question 9

Which proteins would be considered peripheral membrane proteins?

A) aquaporins
B) cell adhesion proteins
C) carrier proteins
D) microtubules
E) receptors

Question 10

Which proteins form channels in the membrane that allow selected polar molecules and ions to pass through and across the membrane?

A) transport proteins
B) recognition proteins
C) receptor proteins
D) cell adhesion proteins
E) nuclear proteins

Question 11

Which type of lipid is most important to the structure of biological membranes?

A) fat
B) wax
C) phospholipid
D) neutral fat
E) triglyceride

Question 12

Which molecules demonstrate dual solubility characteristics?

A) sterols only
B) proteins only
C) phospholipids only
D) sterols and phospholipids
E) sterols, phospholipids, and proteins

Question 13

Cystic fibrosis primarily affects which organ?

A) brain
B) heart
C) muscle
D) lungs
E) bones

Question 14

In an aqueous environment, the phospholipids of a membrane ____.

A) are arranged in a single layer
B) are arranged in a bilayer with the polar heads of each layer located at the membrane surface
C) are arranged in a bilayer with the fatty acid tails located at the membrane surface
D) are arranged in a bilayer but the phospholipids have no specific orientation
E) dissociate into their lipid and protein components

Question 15

Membrane sterols, such as cholesterol, function in animal cell membranes to ____.

A) increase the rate of diffusion
B) store cellular energy
C) facilitate ion transport
D) maintain membrane fluidity
E) receive chemical signals

Question 16

Our current view of membrane structure is based on the fluid mosaic model, proposed by ____ in 1972.

A) Frye and Edidin
B) Watson and Crick
C) Singer and Goldstein
D) S. Singer and G. Nicolson
E) Brown and Goldstein

Question 17

Which proteins recognize and bind molecules from other cells that act as chemical signals?

A) transport proteins
B) recognition proteins
C) receptor proteins
D) cell adhesion proteins
E) nuclear proteins

Question 18

Glycolipids and glycoproteins form a surface coat on the outside of the cell surface called a ____, which protects the cell against chemical and mechanical damage.

A) cell wall
B) outer matrix
C) extracellular matrix
D) glycocalyx
E) lipid raft

Question 19

When referring to membrane glycolipids and glycoproteins, the term "glyco-" indicates ____.

A) carbohydrate groups are attached to the molecules
B) the molecules are bound to the glycocalyx
C) the molecules are found on both the interior and exterior of the membrane
D) the molecules are attached to the membrane by ionic bonds
E) the molecules are rarely found on the membrane exterior

Question 20

Which class of proteins is embedded in the phospholipid bilayer?

A) cytoskeletal proteins
B) integral membrane proteins
C) transcription factor proteins
D) peripheral membrane proteins
E) protein hormones

Question 21

Which adaptation to the plasma membrane allows mammals to hibernate in subzero temperatures without their plasma membranes freezing?

A) increase in cholesterol content only
B) increase in protein content only
C) increase in the number of double covalent bonds in phospholipids
D) increase in both cholesterol and protein content
E) increase in both cholesterol and double covalent bonds in phospholipids

Question 22

Movement of a substance from an area of low concentration to an area of high concentration using energy obtained from ATP is called ____.

A) passive transport
B) diffusion
C) facilitated transport
D) osmosis
E) active transport

Question 23

What is the energy source for facilitated diffusion?

A) ATP hydrolysis
B) concentration gradients
C) glucose metabolism
D) GTP hydrolysis
E) lipid phosphorylation

Question 24

A scientist fused a mouse cell and a human cell, then treated the cell with specific antibodies covalently linked to colored fluorescent dyes (antibodies to mouse proteins were labeled green; antibodies to human proteins were labeled red). Forty minutes later, what will the researcher observe?

A) The fused cell will still be half red and half green.
B) The red and green fluorescent labels will be uniformly distributed throughout the entire membrane.
C) The red and green labels will be distributed in intermingled patches.
D) The red and green labels will flash intermittently.
E) The red and green labels will be distributed in a swirling pattern.

Question 25

The ____ component of the cell membrane functions as a selective barrier, while the ____ component has specific functions such as transport, recognizing other cells, and binding to other cells.

A) carbohydrate; nucleic acid
B) protein; lipid
C) lipid; protein
D) lipid; carbohydrate
E) carbohydrate; protein

Question 26

Carrier proteins are utilized for ____.

A) active transport only
B) passive transport only
C) both active and passive transport
D) osmosis
E) transport of all types of molecules

Question 27

The polar end of a phospholipid contains a phosphate group bound to ____, while the nonpolar end contains ____.

A) alcohols or amino acids; two fatty-acid tails
B) glycoproteins; one fatty-acid tail
C) two fatty-acid tails; sterols
D) variable proteins; cholesterol
E) water; choline

Question 28

Which function of cellular membranes is critical to the molecular organization of cells?

A) the controlled transport of ions and molecules across the membrane
B) cell-cell binding
C) recognition of other cells as being "foreign" or "self"
D) reception of chemical signals from other cells
E) participation in metabolic reactions

Question 29

What happens when the concentrations of a solute that can freely diffuse across a membrane are equal inside and outside the cell?

A) The osmotic pressure is equilibrated on both sides of the membrane.
B) Solute molecules no longer diffuse across the membrane.
C) Solute molecules continue to diffuse across the membrane.
D) Transporter proteins are inhibited to prevent movement across the membrane.
E) Channel proteins are gated to prevent movement across the membrane.

Question 30

When a drop of food coloring is placed in a container of clear water, the colored dye molecules ____.

A) diffuse to a different location by osmosis
B) diffuse to a different location by active transport
C) concentrate at the top of the container
D) diffuse equally throughout the container
E) stay at the bottom of the container

Question 31

Facilitated diffusion is specific, which indicates that ____.

A) a specific protein will transport certain polar or charged molecules but not others
B) only one specific integral membrane protein per membrane is involved in this process
C) the energy molecule ATP is specifically required for transport
D) only specific hydrophobic molecules can be transported
E) transport of molecules occurs only in specific cells

Question 32

Which organelle's membrane contains the enzymes that convert light energy to chemical energy in eukaryotes?

A) plasma
B) chloroplast
C) Golgi complex
D) lysosome
E) endoplasmic reticulum

Question 33

Polar and charged molecules typically cross the cell membrane by way of ____.

A) simple diffusion
B) osmosis
C) filtration
D) active transport
E) facilitated diffusion

Question 34

A channel that opens in response to changes in ionic charge across a membrane is called a(n) ____ channel.

A) voltage-gated
B) ligand-gated
C) charge-gated
D) electric-gated
E) positive-gated

Question 35

Carrier proteins are often used by the cell to transport ____.

A) H₂O
B) proteins
C) amino acids
D) steroid hormones
E) CO₂

Question 36

In what way do the various membranes of a cell differ?

A) Phospholipids are found only in certain membranes.
B) Certain proteins are unique to each membrane.
C) Only certain membranes are constructed from molecules with dual solubility.
D) Only certain membranes of a cell are selectively permeable.
E) Some membranes have hydrophobic surfaces exposed to the cytoplasm, while others have hydrophilic surfaces facing the cytoplasm.

Question 37

Transport of a molecule across a cell membrane by facilitated diffusion ____.

A) does not exhibit specificity for a particular type of molecule
B) requires the input of energy
C) depends on a concentration gradient
D) goes against the concentration gradient
E) allows nonpolar uncharged molecules to diffuse across a membrane

Question 38

Aquaporins are ____.

A) pores made of water molecules
B) required for water to enter a cell
C) found only in bacterial cells
D) specific channels for water transport
E) useful for cell signaling

Question 39

The selective permeability of a membrane refers to the ____.

A) movement of a molecule from an area of high concentration to an area of low concentration
B) ability of a substance to pass through any membrane
C) ability of only certain molecules to pass across a membrane
D) need for carrier proteins to transport some molecules across a membrane
E) ability of molecules to be transported across a membrane

Question 40

Which molecules most easily diffuse across a cell membrane?

A) ionic
B) large, polar
C) large, hydrophilic
D) small, hydrophobic
E) large, hydrophobic

Question 41

For osmosis to occur, ____.

A) a selectively permeable membrane must be present
B) a concentration gradient cannot exist
C) cellular energy must be expended
D) pure water must be on one side of the membrane
E) only solutes can pass through the membrane

Question 42

The voltage across a membrane is called the ____.

A) electrochemical gradient
B) turgor pressure
C) membrane potential
D) chemical gradient
E) electron potential

Question 43

Mutations in different types of aquaporin proteins lead to a variety of clinical manifestations, such as diabetes insipidus, epileptic seizures, and cataracts. What best explains the differences in the conditions caused by these mutations?

A) Different types of aquaporin proteins allow different rates of water diffusion.
B) Different aquaporin proteins are localized to different membranes in the cell.
C) Different types of aquaporin proteins are produced in different cell types.
D) Different types of aquaporin proteins alter the amount of water retention within a cell.
E) Different aquaporin proteins have different functions within the cells.

Question 44

The movement of water across a membrane from an area of high to low water concentration is an example of ____.

A) active transport only
B) endocytosis only
C) osmosis only
D) both osmosis and active transport
E) both diffusion and osmosis

Question 45

Which ion is actively transported to regulate pollen growth and fertilization?

A) hydrogen
B) potassium
C) sodium
D) calcium
E) magnesium

Question 46

A red blood cell placed in a beaker of solution immediately begins to swell and ultimately bursts. This occurs because the cytoplasm of the cell was ____ to the solution in the beaker, which was ____.

A) hypertonic; hypotonic
B) hypotonic; hypertonic
C) hypotonic; isotonic
D) hypertonic; isotonic
E) isotonic; hypotonic

Question 47

The movement of water across a membrane from an area of lower solute concentration to a region of higher solute concentration is called ____.

A) osmosis only
B) active transport only
C) endocytosis only
D) both diffusion and osmosis
E) both osmosis and active transport

Question 48

A(n) ____ environment is ideal for plant cells, while a(n) ____ environment is best for animal cells.

A) isotonic; hypotonic
B) hypotonic; isotonic
C) hypotonic; hypertonic
D) hypertonic; isotonic
E) isotonic; isotonic

Question 49

The force that pushes plant cell membranes tightly against the cell wall and helps support softer tissues against the force of gravity is known as ____ pressure.

A) turgor
B) osmotic
C) diffusion
D) concentration
E) plasmolysis

Question 50

In plants, extreme wilting of leaves and stems can cause the cells to retract from the cell wall, a condition known as ____.

A) hemolysis
B) an increase in turgor pressure
C) plasmolysis
D) a lack of solutes in the cell
E) a higher than normal concentration of water in the cell

Question 51

An isotonic solution has a solute concentration ____ the solute concentration inside the cell.

A) equal to
B) greater than
C) less than
D) that depends on
E) that alters

Question 52

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

A) plasmolysis
B) diffusion
C) active transport
D) the cell from bursting
E) the cell from shrinking

Question 53

The Na⁺/K⁺pump creates a ____ charge inside the cell and a ____ charge outside the cell.

A) negative; negative
B) positive; negative
C) positive; positive
D) negative; positive
E) neutral; positive

Question 54

The net movement of molecules or ions from a low concentration to a higher concentration is called ____.

A) active transport
B) facilitated diffusion
C) exocytosis
D) osmosis
E) diffusion

Question 55

A(n) ____ gradient is created as ions diffuse across membranes.

A) chemical
B) electrochemical
C) negative
D) electrical
E) active

Question 56

Two solutions of differing glucose concentration are placed in a container separated by a selectively permeable membrane that restricts large molecules like glucose, but allows the free diffusion of water. What will be the glucose concentration in the container after dynamic equilibrium has been reached?

A) The water molecules will be evenly distributed in the container, with more glucose molecules on one side than the other.
B) The volumes of the solution will be different, with a higher volume on the side that originally contained the higher concentration of glucose.
C) The volumes of the solution will be different, with a lower volume on the side that originally contained the higher concentration of glucose.
D) The glucose concentration of the two solutions will be identical on both sides of the membrane, but the volumes will remain unchanged.
E) The volume and concentrations will be unchanged on both sides of the membrane.

Question 57

Humans with mutations in the AQP1 (aquaporin-1) gene do not produce the AQP1 protein. The absence of AQP1 causes an inability to ____ in these individuals.

A) produce concentrated urine
B) recognize thirst
C) make large volumes of dilute urine
D) control sweating
E) salivate

Question 58

Which process moves materials against a concentration gradient?

A) active transport
B) dialysis
C) facilitated diffusion
D) simple diffusion
E) osmosis

Question 59

The pressure that must be applied to a solution to prevent water movement across a membrane is known as ____ pressure.

A) turgor
B) osmotic
C) diffusion
D) concentration
E) plasmolysis

Question 60

Distilled water is ____ to body cells.

A) isotonic
B) hypertonic
C) hypotonic
D) protonic
E) aquatonic

Question 62

Cells undergo exocytosis ____.

A) to pump protons down a concentration gradient
B) when replicating
C) to secrete protein and wastes from the cell
D) to ingest nutrients
E) as a means of cellular protection

Question 64

In secondary active transport, when both the driving ion and the transport ion are in high concentration outside of the cell, in which direction will the two ions move?

A) As the driving ion moves in, the transport ion moves in.
B) As the driving ion moves in, the transport ion moves out.
C) As the driving ion moves out, the transport ion moves in.
D) As the driving ion moves out, the transport ion moves out.
E) As long as both ions are moving together, they can go either in or out.

Question 65

Pinocytosis and phagocytosis are accomplished in the cell by the ____.

A) nucleus
B) lysosome
C) endoplasmic reticulum
D) plasma membrane
E) mitochondria

Question 67

Bulk endocytosis is also called pinocytosis.

Question 68

Cholesterol is essential for keeping cell membranes from thickening .

Question 69

Where do exocytic secretory vesicles originate?

A) endoplasmic reticulum
B) plasma membrane
C) the Golgi complex
D) lysosomes
E) microbodies

Question 70

Explain why the transport of molecules across the cell membrane is considered to be both specific and directional.

Question 71

A transport system in which the transport of an ion in one direction provides the energy for active transport in the opposite direction is known as ____.

A) antiport
B) active diffusion
C) symport
D) facilitated diffusion
E) osmosis

Question 72

A hypertonic environment would be ideal for a healthy plant.

Question 73

In patients with familial hypercholesterolemia, which cellular process is inhibited?

A) bulk endocytosis
B) receptor mediated endocytosis
C) exocytosis
D) primary active transport
E) secondary active transport

Question 74

In primary active transport, the carrier protein that transports a substance also hydrolyzes ATP to power the transport directly.

Question 75

In order to visualize LDL entry into the cell, researchers tagged the LDL with which heavy metal?

A) iron
B) mercury
C) lead
D) manganese
E) zinc

Question 76

In secondary active transport, when the driving ion concentration is high and the transport ion concentration is low outside of the cell, in which direction will the two ions move?

A) As the driving ion moves in, the transport ion moves in.
B) As the driving ion moves in, the transport ion moves out.
C) As the driving ion moves out, the transport ion moves in.
D) As the driving ion moves out, the transport ion moves out.
E) As long as both ions are moving together, they can go either in or out.

Question 77

People with type A blood have red blood cells that express one type of recognition protein, while those with type B blood express a different recognition protein. People with AB blood express both recognition proteins. Why can a person with AB blood receive blood from a person with type A, but a person with type A blood cannot receive blood from a person with type AB?

Question 78

In receptor-mediated endocytosis, the receptors collect into a depression called a coated pit for endocytosis after the target molecules bind to them.

Question 79

Which molecules coat the inside of the cytosolic membrane to help form endocytic vesicles?

A) clathrins
B) cholesterols
C) antibodies
D) aquaporins
E) microtubules

Question 80

The Na⁺/K⁺pump transports ____.

A) two sodium ions in and two potassium ions out
B) two sodium ions in and three potassium ions out
C) two sodium ions out and three potassium ions in
D) three sodium ions in and two potassium ions out
E) three sodium ions out and two potassium ions in