12.10 - Gas Exchange Flashcards
SA:V RATIO
1) Some materials that need to be interchanged between an organism and its environment for its survival is:
- respiratory gases (_______________)
- nutrients (______________________)
- excretory products (____________________)
- heat
2) exchange takes place at the ________ of an organism
3) For exchange to be effective, the SA of an organism must be ___________ compared to its volume.
4) surface area to volume ratio ____________ as the organism gets LARGER
E.g. cube A is smaller than cube B, cube B’s volume has increased more than its SA so it has a smaller SA:V ratio.
5) A larger organism loses heat ___________ across its surface than a smaller organism.
6) _____ is required to produce ATP in aerobic respiration. A waste product of this is _______. producing conc. gradients of these in opposite directions.
7) single celled organisms e.g amoeba have a ___________________ SA:V ratio to meet their gas exchange needs.
8) Larger organisms have a _____________________ SA:V ratio so can’t rely on diffusion alone for oxygen demands, so have developed ______________________ which have adaptations to ensure the rapid diffusion of gases.
9) Larger organisms have a _____ distance between the cells that are deeper in the body and the outside of the environment, so instead of straightforward diffusion, they need specialised exchange organs, e.g in the lungs _______-
10) Metabolic activity inside cells creates _______. Rate of _______ depends on its SA. A large animal (low SA:V), = _______ rate of respiration. Small animal (high SA:V) = _______ rate of respiration.
1) oxygen + carbon dioxide
glucose, AAs, lipids
CO2 + urea
2) surface
3) large
4) decreases
5) more slowly
6) oxygen, carbon dioxide.
7) large enough
8) relatively small, specialised gas exchange surfaces
9) big, alveoli
10) heat, heat loss, slower, faster.
GAS EXCHANGE IN INSECTS
1) They need gas exchange and also to _________________. Most effective surface for gas exchange = L… T… + P….. area. But these are also favourable for______________ which can lead to dehydration (dessication - dry out + die)
2) To limit water loss, insects may have: ________ covering - rigid outer skeleton + waterproof cuticle. ____________________ SA:V ratio to minimise area of which water is lost.
1) conserve water. Large, thin + permeable area. Evaporation.
2) waterproof covering. Relatively small SA:V ratio.`
MOVEMENT OF GASES + TRACHEAL SYSTEM IN INSECTS
How does oxygen move through the insect? (4m)
// movement of oxygen through the insect //
1) Oxygen enters the insect through….
2) Spiracles…
3) oxygen diffuses through the tracheae into the….. (____ a conc. gradient)
4) Oxygen is delivered directly to the…
(5) [ CO2 PRODUCED BY AEROBICALLY RESPIRING TISSUES MOVES IN THE _____________ DIRECTION + ____ the insect when spiracles ______ ]
// spiracles //
6) Gas enters and exits the insect through these tiny _______. They open and close to….
// tracheae //
7) Network of tubes supported by strengthened rings. Provides ______________________ so that diffusion is fast.
// tracheoles //
8) Small tubes w/ ________ walls so diffusion distance is _________
9) _________________ so that there is a large SA.
1) spiracles then into the tracheae.
2) close
3) tracheoles. DOWN
4) respiring tissues.
5) OPPOSITE, + exits the insect when spiracles open.
6) tiny pores. control water loss by evaporation.
7) Tubes full of air.
8) thin walls, d.d is reduced.
9) highly branched.
DIFFUSION IN GAS EXCHANGE IN INSECTS
//oxygen diffusion//
1) Tissues respire using oxygen which….
2) Oxygen moves from an area of high conc. to low conc. so from…
3) This lowers the oxygen conc. in the tracheae so…
//co2 diffusion//
4) Respiration produces CO2…
5) CO2 moves from an area of high conc. to low conc…
6) CO2 then moves from high conc. to low conc….
7) WHAT ARE THE THREE WAYS GASES MOVE IN AND OUT OF THE TRACHEAL SYSTEM?
What is ventilation (abdominal pumping)?
8) The movement of the insects muscles creates a….
9) They also have small air sacs in their tracheae, muscles around the tracheae contract and..
How do they get additional oxygen during flight?
10) When an insect is at rest…
11) During flight, the insect may respire ____________ and produce some _________ which lowers the ______ __________ of the muscle cells.
12) As the lactate builds up, water passes via osmosis from…
13) This adaptation draws air into the tracheoles close to the muscle cells and therefore…
1) reduces the conc. of oxygen in the respiring tissues
2) The tracheae to the tissue.
3) oxygen moves into the tracheae from outside the insect via the spiracles.
4) Increases the conc. of CO2 at the tissues
5) so from the tissue to the tracheae.
6) from tracheae to outside the insect via the spiracles.
7)
(1) DIFFUSION GRADIENT
(2) MASS TRANSPORT DUE TO MUSCLE CONTRACTIONS SQUEEZING THE TRACHEAE MOVING AIR IN AND OUT (VENTILATION)
(3) END OF TRACHEOLES ARE FILLED WITH WATER.
8) mass movement of air in and out the trachea which increases the rate of gas exchange.
9) pump the air into the sacs deeper into the tracheoles (maintains conc gradient for o2 and co2)
10) water can build up in the tracheoles
11) anaerobically, lactate, water potential
12) the tracheoles into the muscle cells.
13) reduces the diffusion distance for oxygen when its most needed.
Explain the advantage for larger animals of having a specialised system that facilitates oxygen uptake (2)
1) Larger organisms have a smaller SA:V ratio / smaller = larger SA:V ratio
2) Overcomes the long diffusion pathway = faster diffusion
Explain three ways in which an insect’s tracheal system is adapted for efficient gas exchange. (3)
1) Tracheoles = thin walls so short diffusion pathway to cells
2) Tracheoles = highly branched / large no. of them = short diffusion distance
3) Tracheae provide tubes full of air = fast diffusion.
4) Fluid in end of tracheoles that moves out in exercise = faster diffusion through air to gas exchange surface.
Describe how the structure of the insect gas exchange system :
-provides cells with sufficient oxygen
-limits water loss
Explain your answers. (8)
1) Spiracles > tracheae > tracheols
2) Spiracles allow diffusion of oxygen
3) Tracheoles are highly branched so large SA
4) Thin walls of tracheoles = short diffusion distance
5) Tracheole is permeable to oxygen
6) Cuticle/exoskeleton is impermeable so reduces water loss
7) Spiracles can close so less water loss
8) Hair around spiracles reduce water loss.
GAS EXCHANGE IN FISH
1) The ______ are the gas exchange organ in fish. They have a large SA.
2) Each fish has four ____ in each side of its head
3) The gills have finger-like projections called ___________. Each f________ has many l_______ (at 90* to increase SA)
4) water carrying oxygen enters through the fish’s mouth then…
5) then finally water containing little oxygen leaves…
6) lamellae…
COUNTERCURRENT FLOW
7) The position of the filament and lamellae means that…
8) This increases the fish’s ability to..
9)IF CONCURRENT then only…
1) gills
2) gills
3) filaments, filament, lamellae
4) passes through the lamellae on the gill filaments where most of the oxygen is removed
5) through gill opening
6) are positioned at right angles to filaments, they contain capillaries and have a thin epithelium for short distance between water and blood.
7) blood and water flow in opposite directions.
8) absorb oxygen from the water as a diffusion gradient is always maintained.
9) 50% of the oxygen from the water diffuses into the blood.
Describe and explain the advantage of the counter-current principle in gas exchange across a fish gill. (3)
1) Water and blood flow in opposite directions
2) Maintains conc. gradient of O2
3) Diffusion along length of capillary.
Explain two ways in which the structure of fish gills is adapted for efficient gas exchange. (2)
1) Many filaments/lamellae = large SA
2) Lamellae are thin = short diffusion distance
A fish uses its gills to absorb oxygen from water. Explain how the gills of a fish are adapted for efficient gas exchange.(6)
1) Large SA provided by many lamellae
2) Increases diffusion
3) Thin epithelium / short distance between water and blood
4) Water and blood flow in opposite directions
5) Maintains conc. gradient
6) Water always next to blood with lower conc. of oxygen
7) Circulation replaces blood saturated with oxygen
8) Ventilation replaces water as the oxygen is removed.
GAS EXCHANGE IN PLANTS (LEAVES)
//structure of a leaf//
1) In a leaf there is the.. cu___, upper_______, palisade m_____, spongy m_____-, air _____-, lower _________, guard ________ and sto_____
2) What are the three adaptations of a leaf for gas exchange?
// diffusion of co2 for photosynthesis //
3) Mesophyll cells photosynthesise and this…
4) CO2 diffuses from..
5) This reduces the co2 conc. in the air spaces causing…
// diffusion of o2 //
6) Mesophyll cells produce o2…
7) o2 diffuses into..
8) this increases the conc of o2 in the air spaces, causing…
//adaptations to reduce water loss//
9) The air spaces are saturated with…
10) At night, the guard cells close…
11) less co2 is required at this time of day due to…
12) Upper and lower surfaces have a…
1) cuticle, upper epidermis cells, palisade mesophyll cells, spongy mesophyll cells, air spaces, lower epidermis cells, guard cells and stomata.
2) FLAT - large SA:V ratio / MANY STOMATA - pores to allow air to move in and out of leaf / AIR SPACES - short distance between mesophyll cells and air
3) reduces the conc. of co2 in the cells
4) air spaces into the cells
5) co2 to move into the air spaces from the air outside the leaf through the stomata.
6) as a result of photosynthesis
7) the air spaces from the cells
8) o2 to move from the air spaces to outside the leaf via the stomata.
9) water vapour from the xylem and water diffuses from the stomata as it evaporates
10) the stomata to prevent water loss
11) lack of available sunlight for photosynthesis.
12) waxy cuticle
Describe how CO2 in the air outside a leaf reaches mesophyll cells inside the leaf. (4)
1) CO2 enters via stomata
2) Stomata is opened by guard cells
3) Diffuses through air spaces
4) Down diffusion gradient.
XEROPHYTIC PLANTS
They live in dry/arid environments w/ leaf adaptations to reduce water loss.
1) Reduced no. of…
2) Stomata in pits >
3) hairs to trap…
4) rolled leaves >
5) leaves reduced to..
6) thick waxy cuticles >
1) stomata - less SA for water loss (less evaporation)
2) Reduced conc. gradient
3) water vapour - reduces conc. gradient
4) reduced conc. gradient
5) spines - less SA For water loss
6) increased diffusion distance
HUMAN GAS EXCHANGE SYSTEM
1) In mammals, the respiratory surface with the environment is..
2) they provide an efficient G.E surface as they have:..
3) The lungs are made up of the t….., 2 b…. and many b……..s, finally the a…….
4) Alveoli are small sacs at the end of the….. that act as the barrier between…
5) they have a large….. and a dense…… to maintain efficient diffusion rates
6) They have a rich……which circulates blood to maintain….
7) The gases in the alveolar air spaces are separated by the alveolar s….e….. and the endo….. of the capillary.
1) the lungs
2) short diffusion distance and large SA
3) trachea, bronchi, bronchioles, alveoli
4) bronchioles, air in the lungs and the blood
5) Surface area, capillary network
6) blood supply, a large concentration gradient between gases in blood and alveoli
7) squamous epithelium (1 cell thick - short d.d) and the endothelial wall.
