GAS EXCHANGE Flashcards
How does CO2 reaches to mesophyll
CO2 enters via stomata
Stomata opened by guard cells
Disffuses through air spaces
Down diffusion gradient
Xerophytic plants
- Reduced number of stomata = less surface area for water loss
- Stomata in pits = reduced concentration gradient
- Hair to trap water vapour = reduced concentration gradient
- Rolled leaves = reduced concentration gradient
- Leaves reduced to spines = less surface area for water loss
- Thick waxy xuticles = increses diffusion distance
- Low stomata density = smallera area for diffusion
Gas exchange in plants (CO2)
- Mesophyll cells photosynthesises this reduces CO2 in cells
- CO2 diffuses from air spaces into cells
- Reduces CO2 conc. in air spaces causing CO2 to move into air soaces from outside into leaf thrugh stomata
Gas exchange in plants (O2)
- Mesophyll cells produce O2 as a result of photosynthesis
- O2 diffuses into aue spaces fron cells
- Increases conc. of O2 in air spaces, causing O2 to move from air spaces to outside the leaf via stomata
Adaptation of plants for gas exchange
Flat leaf sp gives large surface area to volume ratio
Many stomata to allow wir to move in and out of leaf
Air spaces in leaf sl short distance between mesophyll cells & air
Countercurrent flow
- Blood & warer flow opposite dirrections this maintains a concentration gradient across whole length of gill lamellae
- Increase ability to absorb O2
Fish anatomyy
Gills = gill filaments = many lamellae
Adapations of fosh for gas exchange
Gills have gill filaments so large surface area
Gill fillamenr gas many lammelae
Lammellae is thin epithelium for short diffusion distance
Lammellae conatins large number of capillaries so maintains concentration gradient
How do insects get O2 during flight
Insect respire aerobically
Produces lactate
Lower water potential of muscles cells
Water enters via osmosis from trachea into muscle cells
This reduces diffusion idstance for O2 as this adaptation allows air into tracheoles closer to muscles cells
How does diffusion happen in insects (o2)
- O2 used by respiring tissues
- O2 moves from higher conc. to lower conc. (from tracheoles to tissues)
- Lowers O2 conc in trachea so O2 moves intobthe trachea from outside the insect via spiracles
How does diffusion happen in insect Co2
- Respiration produces CO2
- CO2 moves from highr comc to lower conc ( tissues to trachea)
- Co2 open spiracles as high conc in trachea
Adaptation in insects
Spiracles maintain conc gradient = only open when CO2 level increases / opened & closed to control water loss
Tracheae provides large surface are as tubes full of air so diffusion is faster
Tracheoles =
1. Small tubes with thin layers so less diffusion distance
2. Highly branches sk there is a large surface area
Movement of O2 through inscets
- O2 enetrs the insect through spiracles into trachea. Spiracles closes
- O2 diffuses through trachea into tracheoles
- O2 delivered directly to respiring tissues
Adapatitions of insect dor water loss
Rigid outer skeleton covered with waterproof cuitcle
Small surface area to volume ratio to minimise area over which water is lost
Pulmonary ventilation
P.V = tidal volume x breathing rate
