chapter 3: cellular level of organization

Question 1

concentration gradient

Answer 1

a difference in the concentration of a chemical from one place to another, like inside to the outside of the plasma membrane

Question 2

electrical gradient

Answer 2

a difference in electrical charges between two regions

Question 3

membrane potential

Answer 3

charge difference that occurs across the plasma membrane

Question 4

passive processes

Answer 4

a substance moves down its concentration or electrical gradient to cross the membrane using only its own KINETIC energy

Question 5

Active processes

Answer 5

cellular energy is used to drive the substance uphill against its concentration or electrical gradient

Question 6

vesicle

Answer 6

tiny membrane sac
used by some substances to enter and leave cells in an active process
examples are endocytosis and exocytosis

Question 7

diffusion

Answer 7

is a passive process by kinetic energy.
Solute molecule will move from high concentration to low concentration
moves down its concentration gradient and through out time they get to equilibrium

Question 8

channel mediated facilitated diffusion

Answer 8

a solute moves down its concentration gradient across the lipid bilayer through a membrane channel

Question 9

tonocity

Answer 9

is a solutions measure of its ability to change the volume of cells by altering their water content

Question 10

crystal of dye in cylinder of water experiment

Answer 10

showed that the dye moved from area of high dye concentration to lower dye concentration and reached equilibrium when concentration became uniform throughout.

Question 11

what are the 3 types of diffusion?

Answer 11

simple diffusion - substances move freely through the lipid bilayer of the plasma membrane without help of membrane transport proteins
facilitated diffusion - channel protein or carrier protein assists a substance across the membrane
osmosis - net movement of SOLVENT through selectively permeable membrane

Question 12

what type of molecules move across the lipid bilayer of the plasma membrane via simple diffusion?

Answer 12

nonpolar, hydrophobic molecules

Question 13

osmosis

Answer 13

the movement of water molecules through a selectively permeable membrane

Question 14

why do red blood cells in isotonic solution maintain their shape ?

Answer 14

because there is no net water movement into or out of the cells

Question 15

isotonic solution

Answer 15

any solution where a cell like a RBC maintains its normal shape and volume
concentration of solutes that cannot cross the plasma membrane are the same on both sides of the membrane in this solution
example: 0.9%NaCl

Question 16

hypertonic solution

Answer 16

MOVING WATER INSIDE cell(Enter)
has HIGHER concentration of solutes than in the cytosol
water molecules MOVE OUT of the cells faster causing crenation
example: 2% NaCl

Question 17

hypotonic solution

Answer 17

moving water OUTSIDE cell
has LOWER concentration of solutes than in the cytosol
water molecules ENTER the cells faster causing hemolysis
example: less than 0.9% NaCl

Question 18

osmotic pressure

Answer 18

force exerted by solution with the impermeable solute
the higher the solutes concentration, the higher the solution’s osmotic pressure

Question 19

human somatic cells contain ______pairs of homologous chromosomes

Answer 19

23
46 chromosomes total