movement across membranes- (2.15-2.17)

Question 1

what is diffusion

Answer 1

the random movement of particles from an area of high to low concantration

Question 2

how does temperature affect that rate of diffusion

Answer 2

at higher temperatures, molecules have more kinetic energy so move faster. therefore diffusion occurs faster

Question 3

how does concentration gradient affect diffusion

Answer 3

the molecules will transfer from the high to the low concentration. if it is a high gradient, the molecules will diffuse faster.

Question 4

how does distance affect diffusion

Answer 4

diffusion takes longer if the molecules have to travel further. short distance increases the diffusion

Question 5

how does surface area to volume ratio affect diffusion

Answer 5

larger SA:V ratio, more opportunities for molecules to move, increases diffusion rate

Question 6

what happens in inhalation

Answer 6

diaphragm contracts, moving down and flattening
intercostal muscles contract- moving up and out
volume of thorax increases
air pressure to fall inside thorax
air moves into lungs

Question 7

what happens in exhalation

Answer 7

diaphragm relaxes, moving up and doming
intercostal muscles relax, moving ribcage down and in
volume of thorax decreases
air pressure rises
air moves out of lungs

Question 8

how is the alveoli adapted for gas exchange

Answer 8

large number of alveoli- large surface area
surrounded by a network of capilliaries - maintains a high concentration gradient
only one cell thick- short diffusion distance

Question 9

animal cells do not have a cell wall
explain how this difference affects red blood cells when places in distilled water

Answer 9

-water moves into the cells via osmosis
-from high to low water concentration
-causing them to swell/burst

Question 10

animal cells do not have a cell wall
explain the differences in the appearance of the cell in distilled water and the cell in the concentrated solution of sodium chloride

Answer 10

distilled water- water enters the cell
-via osmosis
-cell is turgid
concentrated solution-water exits
-by osmosis
-from high to low water concentration
-cytoplasm shrinks away
-cell is flaccid

Question 11

explain the factors that affect the rate of movement of substances into and out of cells

Answer 11

-temp increases- more particle kinetic energy
-high concentration gradient- more movement
-shorter distance increases diffusion
-surface area-volume ratio increases diffusion
-increased oxygen- more energy for active transport

Question 12

describe the differences between diffusion and active transport

Answer 12

-diffusion is passive
-diffusion is from high to low conc, active transport is from low to high conc
-active transport requires energy
-active transport requires membrane/carrier proteins
-diffusion can take place in non-living systems