3.3.3 gas exchange Flashcards
what do insects do to get oxygen
they don’t have a respiratory transport system for gas exchange so gases diffuse from air into their cells through their tracheal system
adaptations of insects to minimize water loss through spiracles
spiracles close when less oxygen is needed, reducing water loss, waxy exoskeleton is not just impermeable to gases but also water
what is a spiracle
small pores which gases enter and leave body of insect in exoskeleton
what are the small tubes that carry gases to and from cells in an insect
tracheoles
what do tracheoles do
create a larger surface area for diffusion
what do fluid filled tips of tracheoles do
gas exchange happens here between end of tracheoles and muscle cells
during activity, fluid moves into muscle cells, for more sa for diffusion
what does the muscle tissue do
at rest, muscle cells use up oxygen in respiration which creates a conc gradient
during activity, contraction creates a pressure gradient, forcing air in and out of the
process of gas exchange in insects
air moves into trachea via spiracles
oxygen travels down concentration gradient towards the cells
trachea branch off into tracheoles which have thin permeable walls and go directly to individual cells
carbon dioxide form cells moves down concentration gradient towards spiracles to be released into atmosphere
insects use rhythmic ambominal movement to move air in and out of spiracles
how are gas exchange surfaces adapted to be efficient
large surface area
short diffusion pathway
large concentration gradient
rich blood supply
what is the site of gas exchange in animals
alveoli in lungs
single celled organisms are adapted for gas exchange by
thin membrane
partially permeable
large sa:v ratio
short diffusion pathway
why are fish unable to have a tracheal gas exchange system
too large
what are fish gills made up of
gill filaments and lamella
how does lamella create a large surface area
gill filaments are covered in lamella= larger surface area for gas exchange
he does many lamella create a rich blood supply
lamella have many capillaries inside and the large amount of lamella means a rich blood supply
what does having a rich blood supply allow
maintaining concentration gradient
short diffusion pathway
what type of gas exchange system do fish use
counter current system
what does counter current mean
blood flows through lamellae , water flows over lamellae in the opposite direction= large concentration gradient between water and blood across the whole lamellae so there is faster gas exchange from water to blood
what is the equation for photosynthesis
carbon dioxide + water > oxygen + glucose + energy
6CO2 + 6H2O > C6H12O6 + 6O2 + ATP
name layers of a leaf from top to bottom
waxy cuticle
upper epidermis
palisade mesophyll
spongy mesophyll
lowe epidermis
stomata + guard cells
waxy cuticle
guard cells and stomata- gas exchange
gas enters and leaves leaf through stomata
opening and closing of stomata is controlled by guard cells
in light, guard cells swell with water= stomata opens
in dark, they shrivel to prevent water loss as stomata closes
ways xerophytes (plants that live in extreme environments) are adapted
stomata sunken in pits
layer of hairs on epidermis
curled leaves with stomata inside
reduced number of stomata
waxy cuticle
how is the adaptation of xerophytes having their stomata sunken in pits efficient
traps moist air to collect water and reduced concentration gradient
how is the adaptation of xerophytes having a layer of hairs on epidermis efficient
trap moisture
how is the adaptation of xerophytes having curled leaves with stomata inside efficient
protects from wind
less transpiration
how is the adaptation of xerophytes having a reduced number of stomata efficient
reduced water loss
how is the adaptation of xerophytes having a waxy cuticle efficient
reduces water loss via evaporation/ transpiration
what is the function of the blood
carry substances around the body
what is the function of haemoglobin
responsible for the co transport of oxygen and carbon dioxide
what are the features of haemoglobin
it’s a protein found in red blood cells
made up of 4 polypeptide chains
quaternary protein
each chain is associated with a haem group contains iron
carries 4 oxygen at a time
what is the process of haemoglobin transporting oxygen
picking up oxygen at the lungs (loading)
transporting through the blood
dropping oxygen off at respiring tissue (unloading)
what does fully saturated mean
haemoglobin is bound to 4 oxygen molecules- forming oxyhaemoglobin
what are the 2 jobs of haemoglobin
loading oxygen at the lungs and unloading at respiring tissues
how can haemoglobin do it’s 2 contradictory jobs
its shape
depending on the oxygen partial pressure
carbon dioxide partial pressure
PH
temperature
what is partial pressure
way of measuring the proportion of a mixture of gases that a specific gas occupies
