Organism's exchange substances with their environment Flashcards
+how are Alveoli specialised for gas exchange ?
- capillary once cell thick
- thin walls - short diffusion pathway
-good blood supply , produces a concentration gradient of oxygen
why do all living organisms need to exchange things within their environment ?
so organisms can survive . waste products need to be released from body as toxic and harmful to body .
what 3 factors will affect how many exchange of substances there are and how easy it is to remove them ?
- size of organisms ( bigger the size , the bigger the diffusion pathway)
- surface area : volume ratio( larger organism =smaller SA:Vol )
- level of activity - more metabolic processes = more waste products formed so more exchange substances .
how to calculate surface area and volume of a cube ?
SA = L x w x how many faces
volume = L x W x H
what does it mean to have a larger surface area ?
more surface area available for gas exchange of materials , making it easier for the organism to absorb necessary nutrients and eliminate waste products .
why do single celled organisms not need specialised exchange surfaces ? Amoeba
They use diffusion for gas exchange as it is sufficient . the diffusion pathway is short and cytoplasm is close to the environment so it has a high SA:Vol
what are 5 features of specialised exchange surfaces ?
- a large surface area relative to volume ratio of organism
- very thin
-selectively permeable - movement of the environment medium
- a transport system
why is a large surface area to volume ratio a feature of exchange surfaces ?
this increases rate of change
why are exchange surfaces relatively thin ?
to have a short diffusion distance so materials can cross exchange surfaces rapidly
why is an exchange surface suppose to be selectively permeable /
to allow selected materials to cross
why is movement of environmental medium important feature of specialised exchange surface ?
to maintain a diffusion gradient - air
why is a transport system important feature of specialised exchange surfaces ?
to move internal medium to maintain a diffusion gradient - blood .
what are 3 structures of tracheal system in insects ?
- tracheae
- tracheoles
-spiracles
what is tracheae in insects ?
a network pf tubes
supported by strengthened rings to prevent the from collapsing
what is tracheoles ?
small dead tubes
extend through all body tissue
atmospheric air bright directly respiring tissue ( don’t rely on blood )
diffusion pathway short
what are spiracles ?
tiny pores which gas enter and leave from on body surface
-these can be opened and closes by valve
- when open water vapour can evaporate from inset
- often kept closed to prevent water loss .
what are 3 ways of movement of respiratory gases in tracheal system
- along diffusion gradient
- mass transport
-end of tracheoles are filled with water
how can respiratory gases move along a diffusion gradient in insects ?
- during respiration , cells use oxygen up so now low concentration gradient of o2 near end of cells
- diffusion gradient produced
- o2 diffuses from atmosphere through tracheae , tracheoles sand into cell
- respiring cells have a high concentration of co2 in cell so that diffuses out of insect into atmosphere .
how can respiratory gases move by mass transport ?
contraction of muscles in insects can squeeze tracheae enabling gas moving in and out
- by rhythmic abdominal movements which increase pressure in body
- move air out of spiracles during vigorous activity
how can movement of respiratory gases occur when end of tracheoles are filled with water ?
- during high activity muscles can respire anaerobically
- produces lactic acid which is soluble
-lowers water potential in muscles - water moves in from tracheoles by osmosis
-water volume in end of tracheoles decreases
-air drawn within them
-
what are limitations of tracheal system ?
- relies mostly on diffusion for gas exchange - slow
- pathway NEEDS to be short to be effective
- limits the size the insect can reach
where are gills located ?
In body of fish behind the head Behind the head
what are the 2 structures of a gill
- gill filaments
gill lamellae
what are gill filaments structure ?
stacked fillaments attached to gill arch
what are gill lamellae ?
at right angles to filaments , arranged rows , to increase surface area of the gills
how are gills adapted to have a large surface area to volume ratio ?
there are many gill filaments covered in many gill lamellae
how are gills adapted to have a short diffusion pathway ?
short diffusion distance due to :
- capillary network in every lamellae
- all gill lamellae are very thin
how are gills adapted to maintain a concentration gradient ?
counter current flow mechanism
describe counter current flow in gills of fish ?
- blood and water flow in opposite directions
- oxygen concentration gradient is maintained along whole length of capillary
- equilibrium is never reached
(so water with lowest oxygen concentration found adjacent to most deoxygenated blood )
plants are autotrophs , what does this mean ?
they do respiration in chloroplast
use CO2 to produce O2
what is a dicotyledonous leaf ?
a flowering plant or leaf
gas exchange processes in palisade mesophyll ?
- lets light through
- photosynthesis occurs
-produces O2 and C6H12O6
gas exchange in spongy mesophyll ?
- lots of space
-movement of gases
-large SA to V
stomata processes for gas exchange ?
-pores which allow gasses diffuse through
-interconnecting air spaces
-short diffusion pathway
how does a leaf have a large surface area ?
spogy mesophyl provides alot of spaces for gases to diffuse
-leaf flat surfacxe
how does a leaf have a short diffusion pathway ?
- stomata pores allows gases to diffuse through
how do leaves maintain a concentration gradaient ?
level of O2 in cell higher than atmoshperen
-level of CO2 in cell is lower than atmosphere
diffusion takes place
3 gas exchange surfaces in plants with cause conflict with limiting water loss ?
-thin
-lge SA:V
-permeable
what are xerophytes ?
plants with restricted water supply e.g marram grass and cactus
how are xerophytes adapted for limiting water loss
5 ways
-curled leaf’s trap moisture , increase humidity
-hairs trap moisture , increase humidity ]
-stomata trap moisture , increase humidity
-thicker waxy cuticle reduce evaporation - longer diffusion pathway
-longer root network - reach more water
how do insects limit water loss - 3 ways ?
- small SA:V
-waterproof exoskeleton made of chitin
-spiracles open and close to reduce water loss
why are the lungs located inside the body ?
-air is not dense enough to support the structures
- body would lose a large amount of water
state the number of different cells and tissues along with the lungs
-ciliated epithelial cells
-goblet cells
-mucous glands
-cartilage
-smooth muscle
-squamous epithelial tissue
trachea structure
-first process of respiration
-flexible airway supported by cartilage rings
-cartilage prevents trachea from collapsing
-walls made of muscle
-lined with ciliated epithelial and goblet cells
bronchi structure
2 diversions of trachea
amount of cartilage reduced with size of bronchi
bronchiole structure
branching subdivisions of bronchi
wall made of muscle , lined with epithelial cells
muscle allow them to constrict and control flow of air
ribcage structure
protects lungs
bony box - supports and priotects lungs
ribs can be moved by intercostal muscles (internal and external )
lungs structure :
-air sacks absorb o2 and exchange co2 for o2
-provide o2 to deoxygenated blood
alveoli structure?
mini air sacs found at bottom of bronchioles
-between alveoli are collagen and elastic fibres to allow it to stick
gas exchange surface
once cell thick
lge SA:Vol
2 reasons why humans need to absorb a large volum3e of oxygen from lungs ?
-lge organisams =large volume of cells so they have a high metabolic rate
-high body temperature