Chapter 3 Cell Transport

Question 1

What are the functions of the plasma membrane?

Answer 1

protection, selective permeability, recognition, adhesion

Question 2

What is meant by “fluid mosaic model”?

Answer 2

the components of the plasma membrane, which fluidly change position: phospholipid bilayer, proteins, cholesterol, and glycocalyx

Question 3

What does “hydrophilic” mean?

Answer 3

“water-loving”, attracts water (repels lipids)

Question 4

What does “hyrophobic” mean?

Answer 4

“water-fearing”, repels water (attracts lipids)

Question 5

Describe the structure of the plasma membrane.

Answer 5

polar head and non-polar tail, arranged tail-to-tail; gives cell ability to control movement of molecules in and out of the cell

Question 6

What are the components and function of the glycocalyx?

Answer 6

glycoproteins and glycolipids: self recognition, determine blood type, immunity response, cell-to-cell interactions

Question 7

What are the three main types of membrane junctions?

Answer 7

tight junction, desmosome, gap junction

Question 8

Where would you find tight junctions?

Answer 8

between cells in lining of digestive tract

Question 9

Where would you find desmosomes?

Answer 9

between skin cells

Question 10

Where would you find gap juctions?

Answer 10

between heart cells and embryonic cells

Question 11

What is a concentration gradient?

Answer 11

a difference in solute concentration on either side of a cell membrane

Question 12

What are the six main functions of membrane proteins?

Answer 12

enzymes, receptors for hormones, cell recognition, cell adhesion, cytoskeleton attachment, transport (channels)

Question 13

What is diffusion?

Answer 13

movement of substances from an area of high to low concentration (down concentration gradient)

Question 14

What is osmosis?

Answer 14

movement of WATER across a membrane down its concentration gradient

Question 15

What substances pass easily through the plasma membrane?

Answer 15

small, lipid-soluble molecules (tails are non-polar, hydrophobic)

Question 16

What is facilitated diffusion?

Answer 16

diffusion of large molecules across a membrane using a protein carrier (channel protein); no energy is required

Question 17

What are the types of passive transport?

Answer 17

diffusion, osmosis, facilitated diffusion, filtration

Question 18

What are the types of active transport?

Answer 18

bulk transport, solute pumping (Na+/K+ pump), exocytosis, phagocytosis, bulk-phase endocytosis, receptor-mediated endocytosis

Question 19

How does the flow of sodium and potassium ions in differ in passive and active transport?

Answer 19

passive-sodium diffuses in cell, potassium diffuses out; active- 3 sodium ions pumped out of cell, 2 potassium ions pumped in per ATP molecule

Question 20

What would happen to a cell in a hypertonic solution?

Answer 20

A hypertonic solution contains more solutes than inside the cell; water moves out and cell crenates (shrinks)

Question 21

What would happen to a cell in a hypotonic solution?

Answer 21

A hypotonic solution contains less solutes than inside the cell; water moves into the cell and cell swells or lyses

Question 22

What would happen to a cell in an isotonic solution?

Answer 22

An isotonic solution contains the same amount of solutes on both sides of the cell membrane; no net water movement and cell stays the same

Question 23

What is a pseudopod?

Answer 23

temporary projections of the plasma membrane used in movement and phagocytosis (macrophages)