gas exchange

Question 1

what does an organism need for efficient gas exchange

Answer 1

large surface area to volume ratio
short diffusion pathway
permeable/ moist
large concentration gradient

Question 2

how are amoeba adapted for gas exchange

Answer 2

large surface area to volume ratio
thin cell membrane so diffusion is rapid
short diffusion distance due to the single cell being thin

Question 3

how are flatworms adapted for gas exchange

Answer 3

flat so have a larger surface area to volume ratio and short diffusion pathway because no part of the body is far from the surface

Question 4

how are earthworms adapted for gas exchange

Answer 4

skin provides a moist respiratory surface by secreting mucus
slow moving so low metabolic rate
oxygen carried away at surface creates a diffusion gradient at respiratory surface

Question 5

how does oxygen diffuse into an earthworm

Answer 5

oxygen diffuses through skin into blood capillaries underneath

Question 6

how have animals in vertebrate groups adapted to minimise water loss

Answer 6

gills -not functioning outside of water
internal lungs to prevent water and heat loss

Question 7

how are amphibians adapted for gas exchange

Answer 7

moist and permeable skin surface gas exchange can take place in skin and also lungs when the frog is active

Question 8

how are reptiles adapted for gas exchange

Answer 8

lungs have a more complex internal structure for increasing surface area

Question 9

how are gills adapted for gas exchange

Answer 9

have a one way current of water
many folds for increased surface area

Question 10

why is ventilation less effective in cartilaginous fish than in bony fish

Answer 10

they have no mechanisms to force water over gills so have to constantly be swimming
oxygen can only diffuse into the blood until the concentration is the same as in the water so bloods max oxygen concentration is 50%

Question 11

what type of flow occurs in cartilaginous fish

Answer 11

paralell flow

Question 12

what is counter current flow

Answer 12

blood and water flow at opposite directions at the gill lamellae maintaining the concentration gradient and oxygen diffusion into the blood along the entire length

Question 13

how much oxygen do the gills remove from water in bony fish

Answer 13

around 80%

Question 14

how does the operculum ventilate the mouth

Answer 14

acts as a valve to let water out and as a pump to moving water past the gill filaments

Question 15

how is water pushed over the gill filaments

Answer 15

by pressure differences because pressure in mouth cavity is higher than it is in the opercular cavity

Question 16

what happens to gill lamellae outside of water

Answer 16

they stick together and the gills collapse not enough area for gas exchange

Question 17

how does CO2 exchange in bony fish

Answer 17

it diffuses out of the blood across the whole length of the gill lamellae

Question 18

how are gills adapted for efficent gas exchange

Answer 18

specialised respiratory surface rather than whole body
large SA
large network of blood capillaries with blood carrying haemoglobin

Question 19

why is breathing an active process

Answer 19

because muscle contraction requires energy

Question 20

why is it important for lung tissue to be elastic

Answer 20

lungs recoil and regain their orignal shape when not being actively expanded

Question 21

what is the surfactant in the alveoli made of

Answer 21

protein and phospholipid

Question 22

what is the function of the surfactant in the alveoli

Answer 22

to allow gases to diffuse into it and prevent alveoli collapsing during exhalation

Question 23

how do insects prevent water loss

Answer 23

they have waterproof /waxy chitin exoskeletons

Question 24

how do insects gas exchange

Answer 24

they have spiracles which branch into tracheoloes
during activity contractions of abdomen ventilate the trachae

Question 25

what happens if water leaves the stomata

Answer 25

they become flaccid and the pore closes

Question 25

which part of the leaf controls the gas exchange

Answer 25

the stomata

Question 26

what happens if water enters the guard cell

Answer 26

they become turgid and the pore opens