6 exchange Flashcards
when an object gets bigger, will it have a bigger or smaller surface area to volume ratio?
smaller
what do all organisms rely on for respiration?
diffusion
do single celled organisms have a big or small SA:V?
big
what can single celled organisms do due to their big SA:V?
diffuse all O2 and CO2
do large organisms have a big or small SA:V?
small
what have large organisms had to do due to their small SA:V?
adapt to ensure rapid movement of gas
how would an amoeba respirate?
diffuse O2 through cell membrane and diffuse CO2 out of cell membrane
what does fick’s law state?
diffusion pathway
what makes a good exchange surface?
large surface area
large conc grad
small exchange surface
how do some insects limit water loss?
waterproof covering
small SA:V
name the feautures of an insects gas exchange system
tracheoles
tracheae
spiracles
what are spiracles?
small pores on exoskeleton that open and close
what are tracheae?
tubes supported by strengthened rings
what are tracheoles?
small branched tubes that come off the tracheae through to the body tissues
how does oxygen move through an insect?
- oxygen enters the insect through spiracles and into the tracheae
- spiracles close
- oxygen diffuses through tracheae into tracheoles
- oxygen is delivered directly to the respiring tissues.
why do the spiracles open and close?
to prevent water loss by evaporation
what is the structure and function of the tracheoles?
- small tubes with THIN walls so the diffusion distance is small
- highly branched so large surface area
what is the structure and function of the tracheae?
tubes full of air so diffusion is fast
why does diffusion happen within the insect?
large amount of O2 outside insect, small amount of O2 at respiring tissues
large amount of CO2 at respiring tissues, small amount of CO2 outside insect
why does insect movement speed up the rate of gas exchange?
muscles contract around the tracheae pushing air into tracheoles
what happens when an insect is resting?
water can build up in tracheoles
what may happen when insects are at flight?
anaerobic respiration producing lactic acid
how does lactic acid help water travel through tissues via osmosis in insects?
lowers water potential
why does lactic acid ultimately help the diffusion of oxygen in insects
lowers diffusion distance by allowing water to travel through muscles by osmosis
what is the gas exchange organ in fish?
gills
why are gills good for gas exchange?
large surface area
describe the structure of the fish gas exchange system
- gill arch
- blood vessels
- gill filaments
- lamellae
- lamellae contain capillaries
explain how the structure of the fish gas exchange system is adapted to its function
- many filaments- large surface area
- lamellae thin- short diffusion pathway
what is countercurrent flow?
the blood and water in the lamellae flow in different directions
why does a countercurrent flow increase the fish’s ability to absorb oxygen from the water?
diffusion gradient is always maintained across the whole length of the lamellae
which has a higher oxygen concentration- blood or water?
blood
what is the equation for photosynthesis?
6CO2 + 6H2O -> 6O2 + C6H12O6
describe the structure of a leaf
- cuticle
- upper epidermis cells
- palisade mesophyll cells
- spongy mesophyll cells
- air space
- lower epidermis cells (guard cells)
- stomata
what is the function of a waxy cuticle?
minimise evaporation
what are some adaptations of the leaf for gas exchange?
many stomata- allow air to move in and out
flat- large SA:V
air spaces- short distance between mesophyll cells and air