Kapitel 10

Question 1

Having both hydrophobic and hydrophilic regions - as in a phospholipid or a detergent molecule.

Answer 1

amphiphilic

Question 2

Pigmented protein found in the plasma membrane of a salt-loving archaeon - Halobacterium salinarium (Halobacterium halobium). Pumps protons out of the cell in response to light.

Answer 2

bacteriorhodopsin

Question 3

The carbohydrate-rich zone on the eukaryotic cell surface attributable to glycoproteins - glycolipids - and proteoglycans of the plasma membrane.

Answer 3

carbohydrate layer

Question 4

An abundant lipid molecule with a characteristic four-ring steroid structure. An important component of the plasma membranes of animal cells. (Figure 10–4)

Answer 4

cholesterol

Question 5

The cytoskeletal network in the cortical region of the cytosol just beneath the plasma membrane.

Answer 5

cortex

Question 6

Small amphiphilic molecule - more soluble in water than lipids - that disrupts hydrophobic associations and destroys the lipid bilayer thereby solubilizing membrane proteins.

Answer 6

detergent

Question 7

Any glycolipid having one or more sialic acid residues in its structure. Found in the plasma membrane of eukaryotic cells and especially abundant in nerve cells. (Figure 10–16)

Answer 7

ganglioside

Question 8

Lipid molecule with a sugar residue or oligosaccharide attached. (Panel 2–5 - pp. 98–99)

Answer 8

glycolipid

Question 9

Lipid linkage by which some membrane proteins are bound to the membrane. The protein is joined - via an oligosaccharide linker - to a phosphatidylinositol anchor during its travel through the endoplasmic reticulum. (Figure 12–52)

Answer 9

glycosylphosphatidylinositol anchor (GPI anchor)

Question 10

Dissolving readily in water. Literally - “water-loving.”

Answer 10

hydrophilic

Question 11

Not dissolving readily in water. Literally - “water-fearing.”

Answer 11

hydrophobic (lipophilic)

Question 12

Protein that binds tightly to a specific sugar. Abundant lectins from plant seeds are used as affinity reagents to purify glycoproteins or to detect them on the surface of cells.

Answer 12

lectin

Question 13

Thin double sheet of phospholipid molecules that forms the core structure of all cell membranes. The two layers of lipid molecules are packed with their hydrophobic tails pointing inward and their hydrophilic heads outward - exposed to water. (Figure 10–1 and Panel 2–5 - pp. 98–99)

Answer 13

lipid bilayer (phospholipid bilayer)

Question 14

Storage form in cells for excess lipids; comprised of a single monolayer of phospholipids and proteins that surrounds neutral lipids that can be retrieved from droplets as required by the cell.

Answer 14

lipid droplets

Question 15

Small region of a membrane enriched in sphingolipids and cholesterol. (Figure 10–13)

Answer 15

lipid raft

Question 16

Artificial phospholipid bilayer vesicle formed from an aqueous suspension of phospholipid molecules. (Figure 10–9)

Answer 16

liposome

Question 17

In cells: volume enclosed by an organelle membrane. In tissues: volume enclosed by a sheet of cells.

Answer 17

lumen

Question 18

Amphiphilic proteins of diverse structure and function that associate with the lipid bilayer of cell membranes. (Figure 10–17)

Answer 18

membrane proteins

Question 19

Membrane proteins not extending into the hydrophobic interior of the lipid bilayer but bound to either face of the membrane by noncovalent interactions with other membrane proteins. (Figure 10–17)

Answer 19

membrane-associated proteins

Question 20

Attach to specific membrane regions as needed and act to control local membrane curvature and thus confer on membranes their characteristic three-dimensional shapes.

Answer 20

membrane-bending proteins

Question 21

Membrane protein in which the polypeptide chain crosses the lipid bilayer more than once. (Figure 10–17)

Answer 21

multipass transmembrane protein

Question 22

Phospholipid derived from glycerol - abundant in biomembranes. (Figures 10–2 and 10–3)

Answer 22

phosphoglyceride

Question 23

The main category of lipids used to construct biomembranes. Generally composed of two fatty acids linked through glycerol (or sphingosine) phosphate to one of a variety of polar groups. (FIgure 10–3 - and Panel 2–5 - pp. 98–99)

Answer 23

phospholipid

Question 24

The membrane that surrounds a living cell. (Figure 10–1)

Answer 24

plasma membrane

Question 25

Membrane protein in which the polypeptide chain crosses the lipid bilayer only once. (Figure 10–17 and 10-24)

Answer 25

single-pass transmembrane protein

Question 26

Abundant protein associated with the cytosolic side of the plasma membrane in red blood cells - forming a network that supports the membrane. Also present in other cells. (Figure 10–38)

Answer 26

spectrin

Question 27

Membrane protein that extends through the lipid bilayer - with part of its mass on either side of the membrane. (Figure 10–17)

Answer 27

transmembrane protein