Midterm 1 - Membranes and Transports

Question 1

selective permeability

Answer 1

• membrane characteristic
• allows some substances through

Question 2

compartmentalization

Answer 2

• separation of cell interior
• distinct compartments , specific local conditions
• diverse metabolic reactions and processes

Question 3

energy transduction

Answer 3

• conversion of one form of energy into another

Question 4

membrane-bound receptor

Answer 4

• transmembrane receptor
• proteins found on the surface of cells
• span the plasma membrane

Question 5

phospholipid

Answer 5

• amphiphilic molecules
• hydrophobic fatty acid chains
• hydrophilic head
• occur naturally in living organisms

Question 6

sterol

Answer 6

• subgroup of steroids
• hydroxyl group at 3-position of A-ring
• amphipathic lipids

Question 6

peripheral membrane protein

Answer 6

• temporarily attached to the cell or mitochondrial membrane

Question 7

integral membrane protein

Answer 7

• integrated into membrane structure
• interacts with the membrane lipids’ hydrocarbon chains
• spans the membrane

Question 7

glycoprotein

Answer 7

• combo of carbs and proteins

Question 8

glycolipid

Answer 8

• combo of carbs and lipids

Question 8

phospholipid bilayer

Answer 8

• thin polar membrane
• 2 layers of lipid molecules

Question 9

self assembly

Answer 9

• components, either separate or linked, spontaneously form aggregates

Question 10

permeability levels

Answer 10

• high: oxygen, steroid hormones
• medium: water, ethanol
• low: large molecules, glucose

Question 11

osmosis

Answer 11

• transport of water through semipermeable membrane
• relates to water’s concentration gradient across the membrane
• results from presence of solute (can’t pass through membrane)

Question 11

simple diffusion

Answer 11

• molecules, atoms, or ions diffuse through semipermeable membrane down concentration gradient
• no assistance from transporter proteins

Question 11

hypotonic environment

Answer 11

• extracellular fluid has lower osmolarity than fluid inside the cell
• water moves into the cell

Question 12

isotonic environment

Answer 12

• extracellular fluid has same osmolarity as fluid inside the cell
• no net water movement in or out of cell

Question 12

facilitated diffusion

Answer 12

• passive movement of molecules along concentration gradient

Question 13

channel protein

Answer 13

• membrane protein
• allows a substance to pass through its hollow core across the plasma membrane

Question 14

gated channel

Answer 14

• integral membrane proteins
• allow regulated flow of selected ions across plasma membrane

Question 14

carrier protein

Answer 14

• membrane protein
• moves a substance across the plasma membrane by changing its own shape

Question 15

active transport

Answer 15

• method of transporting material
• requires energy

Question 15

chemical/concentration gradient

Answer 15

• difference in molecule concentrations across a cell membrane
• high to low concentration

Question 16

electrical gradient

Answer 16

• difference in charge across membrane

Question 16

electrochemical gradient

Answer 16

• combined electrical and chemical force that produces a gradient

Question 17

bulk transport

Answer 17

• moves particles
• endocytosis and exocytosis

Question 17

endocytosis

Answer 17

• active transport
• move substances (fluids and particles) into a cell

Question 18

phagocytosis

Answer 18

• endocytosis
• ingests and eliminates particles
• for homeostasis
• cyt = cell, phago = eating

Question 19

pinocytosis

Answer 19

• endocytosis
• imports macromolecules that the cell needs from the extracellular fluid

Question 19

receptor-mediated endocytosis

Answer 19

• endocytosis
• uses specific binding proteins in plasma membrane for specific molecules or particles

Question 20

exocytosis

Answer 20

• passing bulk material out of a cell