Chapter 5

Question 1

Plasma Membrane

Answer 1

Separates its external environment from the outside world. Regulates passage of materials in and out of the cell; helps maintain homeostasis

Question 2

Amphipathic Molecules

Answer 2

Contains two hydrophobic fatty acid chains linked to two of the three carbons of a glycerol is a negatively charged, hydrophilic phosphate group, linked to a polar, hydrophilic organic group

Question 3

Phospholipids form bilayers of two distinct groups

Answer 3

One strongly hydrophobic and one strongly hydrophilic

Question 4

Cylindrical Shape

Answer 4

Allow phospholipids to associate with water most easily as a bilayer

Question 5

Amphipathic molecules with different shapes ten to form

Answer 5

Spherical structures in water

Question 6

TEM of red blood cell

Answer 6

Hydrophilic heads of phospholipids are the parallel dark lines
Hydrophobic tails are the light zone between them

Question 7

Phosopholipids bilayers behave like

Answer 7

Liquid crystals

Question 8

Membrane fluidity depends on its

Answer 8

Component lipids

Question 9

Biological membranes fuse and form

Answer 9

Closed vessicles

Question 10

Can fuse with other bilayers, allowing vesicles to transfer materials from one compartment to another, or secrete a product from the cell

Answer 10

Biological Membranes

Question 11

Integral Membrane Proteins

Answer 11

Amphipathic proteins firmly bound to the membrane

Question 12

Transmembrane Proteins

Answer 12

Integral proteins that extend completely through the membrane

Question 13

Peripheral Membrane Proteins

Answer 13

Located on inner or outer surface of plasma membranes, bound to exposed regions of integral proteins

Question 14

A specific external domain of an instrinsic membrane protein is always found on the ____ of the membrane

Answer 14

Same side

Question 15

Proteins associated with the membrane specialize for many essential activities

Answer 15

• Anchor the cell to its substrate
• Transport molecules across the membrane
• Catalyze enzymatic reactions near the cell surface
• Receive information from other cells in the form of chemical or electrical signals
• Serve as a identification tag

Question 16

By regulating chemical traffic across its plasma membrane, a cell controls its

Answer 16

Volume and its internal ionic and molecular composition

Question 17

Biological membranes are most permeable to

Answer 17

Small nonpolar molecules

Question 18

The lipid bilayer is relatively impermeable to

Answer 18

Charged ions and most large polar molecules

Question 19

Transport Porteins

Answer 19

Move ions, amino acids, sugars and other needed polar molecules through membranes

Question 20

Two main types of transport proteins

Answer 20

Carrier and Channel

Question 21

Bind the ion or molecules and change shape, moving the molecule across the membrane

Answer 21

Carrier Protein Transporters

Question 22

Transfer of solutes by carrier proteins located within the membrane

Answer 22

Carrier Mediated Transport

Question 23

ABC Transporters

Answer 23

Use energy donated by ATP to transport certain ions, sugars and polypeptides

Question 24

Channel Proteins

Answer 24

Forms pores in membrane. Cells regualte passage of materilas through the channels. Channels transport water and specific types of ions.

Question 25

Porins

Answer 25

Transmembrane channel proteins that allow solutes or water to pass through membranes

Question 26

Aquaporins

Answer 26

Gated water channels that allow rapid transport of water through the plasma membrane

Question 27

Diffusion

Answer 27

The random motion of particles resulting in net movement "down" their own concentration gradient

Question 28

If particles in a liquid or gas are not evenly distributed, then regions exist that have a higher or lower concentration of particles, forming a

Answer 28

Concentration Gradient

Question 29

Osmosis

Answer 29

Diffusion of water: the net movement of water through a selectively permeable membrane from a region of higher concentration of water to a region of lower concentration

Question 30

Osmotic pressure of a solution is exerted on the side of the membrane containing the

Answer 30

Higher concentration

Question 31

Isotonic

Answer 31

No net movement of water molecules occurs between cell and surrounding fluid

Question 32

Hypertonic

Answer 32

A high concentration of solutes exists outside the cell | Cell will lose water and shrink

Question 33

Hypotonic

Answer 33

A lower concentration of solutes exists outside the cell | Cell will gain water and swell

Question 34

Most prokaryotic, algae, plants, and fungi have rigid cell walls that can withstand a ____ solution without bursting

Answer 34

Hypotonic

Question 35

Plasmolysis

Answer 35

When a plasma membrane separates from the cell wall because it is in a hypertonic solution

Question 36

Facilitated Diffusion

Answer 36

A specific transport protein makes membrane permeable to a specific ion or polar molecule

Question 37

In facilitated diffusion, channel proteins

Answer 37

Form hydrophilic channels through membranes

Question 38

Ion channels are referred to as a ____ because they open and close

Answer 38

Gated Channels

Question 39

In facilitated diffusion, carrier proteins bind to solutes to undergo

Answer 39

A change in shape

Question 40

Active Transport

Answer 40

A system across the cell membrane that pumps materials from a region of low concentration to a region of high concentration. Requires the cell to expend metabolic energy

Question 41

Indirect active transport

Answer 41

Concentration gradient provides energy for the co-transport of some other substance

Question 42

The sodium potassium pump

Answer 42

Uses ATP to pump Na ions out of the cell and K ions into the cell

Question 43

In the sodium pump, ____ k are in for every ___ Na ions out

Answer 43

2;3

Question 44

In the sodium pump, membrane becomes

Answer 44

Polarized

Question 45

Uniporters

Answer 45

Transport one type of substance in one direction

Question 46

Symporters

Answer 46

Move two types of substances in one direction

Question 47

Antiporters

Answer 47

Move two substances in opposite directions

Question 48

Proton pump is an example of

Answer 48

Uniporter

Question 49

Cotransported sodium and glucose

Answer 49

Symporters

Question 50

Sodium potassium is an example of

Answer 50

Antiporter

Question 51

Exocytosis

Answer 51

Vesicles export large molecules by the fusion of a vesicle with the plasma membrane

Question 52

Endocytosis

Answer 52

The cell imports materials by phagocytosis, pinocytosis

Question 53

Phagocytosis

Answer 53

Ingesting large solid particles (food or bacteria)

Question 54

Pinocytosis

Answer 54

Taking in dissolved materials

Question 55

Cell Junctions

Answer 55

Connect cells that form strong connections with one another, prevent the passage of materials, or establish rapid communication between adjacent cells

Question 56

Anchoring Junctions

Answer 56

Connect cells of an epithelial sheet

Question 57

Two types of anchoring junctions

Answer 57

Desmosomes and Adhering junctions

Question 58

Desmosomes

Answer 58

Points of attachment that hold cells together at one spot

Question 59

Adhering juntions

Answer 59

Cements cells together

Question 60

Tight Junctions

Answer 60

Seal off intercellular spaces between some animal cells

Question 61

Gap junctions

Answer 61

Allow the transfer of small molecules and ions

Question 62

Plasmodesmata

Answer 62

Allow movement between plan cells