b3.1 gas exchange Flashcards
ventilation system in fish
- extracts oxygen and remove CO2 from water
- has to keep moving or else will reach equilibrium
ventilation system of small organisms
exchange gases directly with their surroundings thru diffusion
alveoli
surrounded by capillaries to continuously bring in fresh blood
why is a ventilation system needed
- large organisms
- land borne
respiration
controlled release of energy from organic compounds to produce ATP
ventilation
movement of air into and out of lungs during inhalation and exhalation
how is ventilation controlled
by movement of ribcage and diaphragm
gas exchange
diffusion of oxygen and carbon dioxide to and from the blood at the alveoli and respiring tissues
where would more stomata be found + why
- lower epidermis
- control loss of water vapour
what happens if transpiration is too quick
- plant will dehydrate and die
shape of open stomata
kidney bean shape
- gap forms in the middle
why doesnt AT2 secrete water
water is polar + cohesive + adhesive
- alveolus will collapse
function of AT2
secretes surfactant
AT1 function
thin so allows for rapid gas exchange
function of surfactant [3]
- prevents collapse
- reduce surface tension
- prevents alveolus from sticking tgt
adaptation of alveolus [4]
- large surface area for gas exchange
- network of capillaries
- maintain high concentration gradient - very thin membranes
- moist surface
- allow for gases to dissolve so gas exchange can occur
tidal volume
amount of air that moves in and out of lungs within each respiratory cycle while breathing nomrally
vital capacity
volume of air after maximum inspiration
respiratory reserve
volume of air inhaled forcefully after normal tidal volume
expiratory reserve
volume of air exhaled forcefully after a normal exhalation
how to identify spongy mesophyll layer
lighter green
function of waxy cuticle
waterproof to reduce water loss
function of spongy mesophyll layer
air spaces for water vapour and oxygen to circulate
function of guard cells
- control opening and closing of stomata
structure of haemoglobin
- 4 chains of polypeptide + 4 haem groups
co-operative binding
binding of oxygen to haemoglobin
characteristic of haemoglobin binding to oxygen (+ states)
either completely saturated (R state) or no oxygen (T state)
where do haemoglobin bind to oxygen
at the lungs
where do haemoglobin lose oxygen
at respiring cells
what happens when oxygen binds
conformational change
- makes other haem groups increase their affinity to bind
when oxygen concentration in atmosphere increase what happens to oxygen saturation level of haemoglobin
positive but non-linear relationship
partial pressure
proportion of total pressure exerted by each gas in a mixture
eq of partial pressure
(air pressure x percentage of oxygen) / 100
at what partial pressure is haemoglobin 100% saturated
30 kPa
what happens when partial pressure is below 10 kPa
releases oxygen to repsiring cells
action of haemoglobin at low kPa
give oxygen
action of haemoglobin at high kPa
take oxygen
how is co-operative binding useful
helps to unload oxygen quickly in tissue where aerobic respiration has to decrease oxygen concentration
why is the oxygen dissociation curve better than a straight line
- can bind to more oxygen at a much lower kPa
- so able to bind even when oxygen concentration is low
- can release oxygen at higher concentration
shape of fetus sigmoid curve
same shape but steeper
why do fetus have a different sigmoid curve
- has to pick up oxygen from maternal blood at the placenta (parasitic relationship)
- high affinity to take more oxygen
result of fetus haemoglobin having higher affinity
can pick up greater proportion of oxygen from adult haemoglobin at any given partial pressure of oxygen
bohr shift
shift in oxygen affinity in haemoglobin due to carbon dioxide concentration
oxygen affinity when there is low carbon dioxide concentration at lungs
- oxygen affinity is higher
haemoglobin binds to oxygen easier at lower partial pressure
oxygen affinity when there is high carbon dioxide concentration at muscles
- oxygen affinity of haemoglobin is lower
- haemoglobin releases oxygen easier to help cell respire aerobically
where does gas exchange occur in the lungs
in type I pnuemocytes
