lesson 20 - gas exchange Flashcards
what is gas exchange?
the process of exchanging oxygen and carbon dioxide between organisms and their environment
what drives gas diffusion?
gases diffuse from high to low partial pressure
how do most animals optimize gas exchange?
they have respiratory organs with large surface
what regulates gas exchange in land plants?
the stomata, controlled by guard cells
what is partial pressure?
the pressure exerted by one gas in a mixture
what is the atmospheric composition at sea level?
nitrogen, oxygen, carbon dioxide
how do some small organisms exchange gases?
direct diffusion across body surfaces
what is ventillation?
helps push water over the gills
what are gills?
instead of lungs this is what animals have and they pull oxygen out of water
what does it mean that fish use a countercurrent exchange system?
blood flows opposite way of water inside the gill. As the deoxygenated blood flows past the water, the blood pulls O2 in through diffusion. The blood is always meeting fresher, oxygen-rich water, it never stops absorbing oxygen! That’s why the opposite flow makes a huge difference.
how efficient are gills at observing O2 from water?
can take more than 80% of the O2 in water
is there more oxygen in water or blood of a fish gill?
water
what are tracheal systems?
network of tiny tubes in insects that delivers oxygen directly to their cells without using blood.
what do aquatic insects with open systems have to give them oxygen while they swim under?
air bubbles
what do closed system insects have to support for oxygen?
gills
where does gas exchange occur in the lungs?
alveoli
what is the difference between positive and negative pressure breathing
negative: pull air into lungs
positive: push air into lungs
what happens do your diaphragm when you exhale?
it relaxes and makes the chest space smaller
what is so special about bird lungs?
the air flows only in one way?
do leaves release CO2 or O2?
oxygen and they take up O2
what happens when plants take in CO2?
water loss
What do plants use to control their oxygen intake and CO2 output
open/close stomata
Light stimulates the entrance of what molecule that allows the the stomata to open
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