Cell Membrane

Question 1

What is the cell membrane

Answer 1

the cellular boundary that holds it together, made up of phospholipids that move rapidly

Question 2

Determinants of membrane fluidity

Answer 2

temperature, saturation of fatty acid tails, cholesterol

Question 3

Effects of cholesterol on membrane fluidity

Answer 3

high temp: cholesterol restricts movement of phospholipids

lower temp: cholesterol prevents packing of phospholipids

Question 4

What the functions of membrane proteins

Answer 4

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment the cytoskeleton and ECM

Question 5

What can get through the membrane

Answer 5

small, non polar molecules like hydrocarbons, CO2, O2)
ions and polar molecules cannot pass easily
STEROID HORMONES CAN FREELY DIFFUSE

Question 6

What is passive transport

Answer 6

a solute in water will move by random collisions
individual solute particle will appear to move at random
solutes move down their concentration gradient (high to low)

Question 7

What is facilitated diffusion/transport

Answer 7

the use of proteins in the membrane to move larger, polar molecules in and out of the cell

Question 8

Tonicity of cells in Hypotonic solution

Answer 8

animal: lysed (burst)
plant: turgid (normal)

Question 9

Tonicity of cells in Isotonic solution

Answer 9

animal: normal
plant: flaccid

Question 10

Tonicity of cells in Hypertonic solution

Answer 10

animal: shriveled
plant: plasmolyzed

Question 11

What is active transport

Answer 11

transport of solutes against their concentration gradient like ions and waste products
requires energy usually from ATP

Question 12

Exocytosis

Answer 12

fusion of vesicle to cell membrane

Question 13

Endocytosis

Answer 13

bringing contents into the cell

Question 14

Phagocytosis

Answer 14

cell eating

Question 15

Pinocytosis

Answer 15

cell drinking

Question 16

What is tonicity?

Answer 16

the ability of a surrounding solution to cause a cell to gain or lose water that depends on solute concentration that connote pass the membrane

Question 17

What is a hypertonic solution

Answer 17

a solution with more solutes that cannot cross the membrane

Question 18

What is a hypotonic solution

Answer 18

water will enter the cell faster than it leaves