Chapter 5 - Membranes

Question 1

Main component of cell membranes; phospholipids naturally associate inside with hydrophobic fatty acids oriented to inside and hydrophilic phosphate groups facing outward on both sides.

Answer 1

Phospholipid bilayer

Question 2

Type of membrane protein that is permanently attached to the biological membrane. All transmembrane proteins are IMPs, but not all IMPs are transmembrane proteins. Comprise a significant fraction of the proteins encoded in an organism’s genome.

Answer 2

Integral protein

Question 3

Proteins that adhere only temporarily to the biological membrane with which they are associated. Attach to integral membrane proteins, or penetrate the peripheral regions of the lipid bilayer.

Answer 3

Peripheral protein

Question 4

A type of membrane protein spanning the entirety of the biological membrane to which it is permanently attached. Span from one side of a membrane through to the other side of the membrane.

Answer 4

Transmembrane protein

Question 5

Protein molecule modified withing the Golgi complex by having a short sugar chaing (polysaccharide) attached

Answer 5

glycoprotein

Question 6

Lipid molecule modified within the Golgi complex by having a short sugar chain (polysaccharide) attached.

Answer 6

glycolipid

Question 7

Carrier-assisted diffusion of molecules across a cellular membrane through specific channels from a region of higher concentration to lower concentration. Driven by concentration from gradient. Doesn’t require ATP

Answer 7

facilitated diffusion

Question 8

Movement of substances across cell’s membrane without expenditure of energy

Answer 8

passive transport

Question 9

Net movement of dissolved molecules or other particles from a region where they are more concentrated to another where they are less concentrated

Answer 9

diffusion

Question 10

A transmembrane protein with a hydrophilic interior that provides an aqueous channel allowing diffusion of species that cannot cross the membrane. Usually allows passage of specific ions such as K+, Na+ or Ca2+

Answer 10

channel protein

Question 11

A membrane protein that binds to a specific molecule that cannot cross the membrane and allows passage through the membrane

Answer 11

Carrier protein

Question 12

Condition in which a membrane is permeable to some substances but not to others (allows some molecules to pass, but not others).

Answer 12

Selectively permeable

Question 13

Pore-forming membrane proteins whose functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions across secretory and epithelial cells, and regulating cell volume.

Answer 13

Ion channel

Question 14

Protein channels that only open under certain conditions.

Answer 14

Gated channel

Question 15

Difference in electric potential between the interior and the exterior of a biological cell.

Answer 15

membrane potential

Question 16

Diffusion of water across a selectively permeable membrane.

Answer 16

Osmosis

Question 17

Solution with a higher concentration of solutes than the cell. Cell tends to lose water by osmosis.

Answer 17

Hypertonic

Question 18

Solution with a lower concentration of solutes than the cell.

Answer 18

Hypotonic

Question 19

Solution with same concentration of solutes as cell.

Answer 19

Isotonic

Question 20

Membrane channel that allows water to cross the membrane more easily than by diffusion through membrane.

Answer 20

Aquaporin

Question 21

Pressure inside a plant cell, resulting from osmotic intake of water. Presses cell membrane tightly against cell wall, making cell rigid.

Answer 21

Turgor pressure

Question 22

Pumping of ind. ions or other molecules across cell membrane from region of lower conc. to one of higher conc. Requires ATP.

Answer 22

active transport

Question 23

Carrier protein in a cell’s membrane that transports only a single type of molecule or ion.

Answer 23

uniporter

Question 24

Carrier protein in a cell’s membrane that transports two molecules or ions in same direction across membrane.

Answer 24

symporter

Question 25

Carrier protein in a cell’s membrane that transports two molecules in opposite directions across membrane.

Answer 25

antiporter

Question 26

Transmembrane channels engaged in active (ATP-driven ) transport of Na+, exchanging them for K+, where both ions are being moved against their respective concentration gradients; maintains the resting membrane potential of neurons and other cells

Answer 26

sodium-potassium pump

Question 27

The linked, simultaneous transport of two substances across a cell membrane

Answer 27

coupled transport

Question 28

Movement of macromolecules such as proteins or polysaccharides into or out of the cell. Exocytosis and endocytosis.

Answer 28

bulk transport

Question 29

A type of bulk transport out of cells in which a vacuole fuses with the plasma membrane, discharging the vacuole’s contents to the outside.

Answer 29

Exocytosis

Question 30

The uptake of material into cells by inclusion within an invagination of the plasma membrane. Phagocytosis & pinocytosis.

Answer 30

Endocytosis

Question 31

Endocytosis of a solid particle; the plasma membrane folds inward around the particle (which may be another cell) and engulfs it to form a vacuole.

Answer 31

Phagocytosis

Question 32

The process of fluid uptake by endocytosis in a cell.

Answer 32

Pinocytosis

Question 33

A protein located just inside the plasma membrane in eukaryotic cells, in indentations called…

Answer 33

Clathrin; clathrin- coated pits

Question 34

Process by which specific macro-molecules are transported into eukaryotic cells at clathrin-coated pits, after binding to specific cell-surface receptors

Answer 34

receptor-mediated endocytosis