Chapter 5: Membranes, The Interface Between Cells and their Environment

Question 1

Permeable

Answer 1

Allowing something to pass through.

Question 1

Impermeable

Answer 1

Things cannot pass through.

Question 2

Semi- or Selective Permeable

Answer 2

Only specific things can pass through.

Question 3

The plasma membrane is made up of…?

Answer 3

Phospholipid bilayer

Question 4

The head of the phospholipid is…

Answer 4

Hydrophilic, and faces out.

Question 5

The legs of the phospholipids are…

Answer 5

Hydrophobic, and faces in.

Question 6

Cholesterol

Answer 6

Helps stiffen the plasma membrane at high temps
Helps with fluidity at low temps.

Question 7

Membrane structure results in…

Answer 7

Selective permeability.

Question 8

What are the six membrane proteins?

Answer 8

Transport
Enzyme
Junction
Attachment
Glycoproteins
Receptor

Question 9

Transport Proteins

Answer 9

Allows specific ions or molecules to enter or exit the cell.

Question 10

What are the two types of transport proteins?

Answer 10

Channel and Carrier

Question 11

What is the difference between Channel and Carrier proteins?

Answer 11

Channel proteins do not require energy.
Carrier proteins require ATP energy which changes their shape.

Question 12

Enzyme Proteins

Answer 12

Grouped
Carry out Reactions
1. Start Reactions
2. Stop Reactions
3. Speed up chemical reactions
4. Slow down chemical reactions

Question 13

Attachment Proteins

Answer 13

HELPS SUPPORT THE MEMBRANE.
COORDINATES EXTERNAL AND INTERNAL CHANGES.
Attach to the extracellular matrix and cytoskeleton.

Question 14

Receptor Proteins

Answer 14

Cell communication!
Signaling molecules bind to receptor proteins.
Receptor proteins relay the message by activating other molecules inside the cell.

Question 15

Junction Proteins

Answer 15

Form intercellular junctions that attach adjacent cells.

Question 16

Glycoproteins

Answer 16

Serves as ID tags.
May be recognized by membrane proteins of other cells.
Glycocalyx

Question 17

What are the two main categories of transport across the plasma membrane?

Answer 17

Passive and Active

Question 18

Passive Transport

Answer 18

Does not require cellular enery.

Question 19

Active Transport requieres?

Answer 19

Cellular energy (ATP)

Question 20

What are the three types of passive transport?

Answer 20

Diffusion, Selective Permeable and Osmosis.

Question 21

Diffusion

Answer 21

Substances move from an area of HIGH concentration to an area of LOW concentration.

Question 22

Concentration Gradient

Answer 22

Occurs when the concentration of substances is higher in one area than another.

Question 23

What affects the rate of diffusion?

Answer 23

Temperature
Molecular Size
Concentration
Pressure

Question 24

Selective Permeable Diffusion

Answer 24

Water can move freely through the membrane, but the membrane regulates the passage of solutes.

Question 25

Osmosis

Answer 25

Movement of WATER across a selectively permeable membrane.
Going from low solute to high solute.
Moving down its own concentration gradient.

Question 26

Active Transport

Answer 26

Moves substances against their concentration gradient.
Requires ATP energy

Question 27

Tonicity

Answer 27

The ability of a solution to cause a cell to gain or lose water.
Depends on the concentration on both sides.
Dictates the direction of diffusion.

Question 28

Isotonic Solution

Answer 28

Solute concentration is the SAME as that inside the cell; no net water movement across the plasma membrane.

Question 29

Hypertonic Solution

Answer 29

Solute concentration is GREATER than that inside the cell; the cell loses water.

Question 30

Hypotonic Solution

Answer 30

Solute concentration is LESS than that inside the cell; the cell gains water.

Question 31

Solute

Answer 31

Dissolved substances (dissolved in water)

Question 32

Facilitated Diffusion

(Three Points)

Answer 32

• Does not require energy
• Relies on the concentration gradient
• Does NOT require transport proteins.

Question 33

Passive Transport

(three points)

What makes it different from Facilitated Diffusion?

Answer 33

• Does not require energy.
• Relies on the concentration gradient.
• A solute moves through a membrane transport Protein **

Question 34

Aquaporin

Answer 34

A channel that makes it possible for water to rapidly diffuse into and out of certain cells.

Question 35

Electrogenic Pump

Answer 35

A transport protein that generates a voltage across the membrane.

Question 36

What is the major electrogenic pump of animal cells?

Answer 36

Sodium-Potassium pumps

Question 37

What is the major electrogenic pump for plants, fungi and bacteria?

Answer 37

Proton Pump

Question 38

Cotransport

Answer 38

Occurs when active transport of solute indirectly drives transport of other solutes.

Question 39

Endocytosis

Answer 39

Used to import substances useful to the livelihood of the cell.

Question 40

Exocytosis

Answer 40

Used to export bulky molecules, such as proteins or polysaccharides.

Question 42

What are the three types of Endocytosis?

Answer 42

Phagocytosis
Pinocytosis
Receptor-Mediated Endocytosis

Question 43

Phago-

Answer 43

to eat

Question 44

Phagocytosis

Answer 44

“Cell eating” large items (such as food, and other cells) are brought into cells in a vacuole.

Question 45

Pino-

Answer 45

To drink

Question 46

Pinocytosis

Answer 46

“Cell drinking” fluid is brought into the cell vesicles.

Question 47

Receptor-Mediated Endocytosis

Answer 47

Specific molecules bind to receptors and then enter the cells in vesicles.