Gas Exchange Flashcards
1
Q
Explain the advantage of having a specialised system that facilitates oxygen uptake.
A
- larger organisms have a smaller surface area:volume ratio\
- faster diffusion rate
2
Q
How does oxygen move through the insect?
A
- oxygen diffuses through spiracles
- spiracles close
- oxygen through trachea to tracheoles
- delivered directly to respiring tissues
3
Q
How is an insects tracheal system adapted for gas exchange?
A
- thin walls so shorter diffusion distance
- highly branched so short diffusion distance and large surface area
- trachea provide tubes full, of air so faster diffusion rate
- fluid in tracheole ended move out during excersise so larger surface area
4
Q
How does an insects gas exchange structure reduce water loss?
A
- exoskeleton so impermeable to water
- spiracles close to reduce water loss
- hairs around spiracles reduce water loss
5
Q
Describe and explain the counter-current principle in gas exchange for fish.
A
- water and blood flow in opposite directions
-maintains diffusion gradient of oxygen - diffusion along length of lamellae
6
Q
Explain how gills of a fish are adapted for efficient gas exchange.
A
- large surface area by many lamellae
- increases diffusion
- thin epithelium between water and blood
- counter-current principle
- maintain concentration gradient of oxygen
- circulation replaces blood with oxygen
- ventilation replaces water
7
Q
Describe how carbon dioxide in the air outside a leaf reaches mesophyll inside.
A
- CO2 in via stomata
- stomata opened by guard cells
- diffuses through air spaces
- down diffusion gradient
8
Q
Why do plants grown in little water grow slow?
A
- stomata close
- less carbon dioxide so less photosynthesis
9
Q
Adaptations of xerophytic plants to reduce water loss include…
A
- reduced stomata = less surface area
- stomata in pits = reduced concentration gradient
- hairs to trap water vapour
- rolled leaves = reduced conc gradient
- thick waxy cuticle = increased diffusion distance
10
Q
Fick’s Law =
A
Rate of diffusion = surface area x concentration gradient / diffusion distance off pathway
11
Q
What makes a good exchange surface?
A
- large surface area
- large concentration gradients
- thin exchange surface
