gas exchange-specification based questions

the relationship betweenn the size of an organism or the structure AND its surface area to volume ratio

as the size of the organism increeases the SA:V decreases

wen gvng two uncertainties: multiplying or dividing the length, what should you do with the uncertainties

Find the percentage uncertainty of each uncertainty

using agar blcks to dtmn the effect of SA:V

cut three agar blocks that have an increasing size, each agar block containing a coloured solution

emerge three blocks into solution

time how long it takes for the solution to change color

expected the one with largest SA:V should change color first

Gas exhange

GAS EXCHANGE

adaptations for a single celled organism

large surface area

increased rate of diffusion for gases across its membrane, concentration gradient is always maintained,

may have a high metabolic rate, if active so more heat loss

the tracheal system consists of

tracheae

spiracles and tracheoles

adaptations of tracheal system

highly branched tracheoles, so increased surface area

highly branched tracheoles so short diffusion pathway

tracheae provides tube filled with air so increased rate of diffusion

fluid at end of tracheoles, so moves into cells when the tissue is active, spaace for gses to diffuse through

body contraction, for gases to pass through

adaptatons of the gillls of a fish

fillaments are stacked upon each other, so increased surface area

rich blood supply so maitains concentration gradient

counter current mechanism (blood and water flow in opposite directions so maitain oxygen concentration gradient along lamallae)

lamallae increased surface area

filaments are thin so short diffusion pathway

adaptations of a dicoltyydenous leaf

mesophyll layer-

differentiated into columnal pallisade contaiions a lot of chloroplasts and spongy cells which are moist, facillate the diffusion of gases

air spaces for the diffusion of gases

stomata- closes to prevent water loss by evaporation

gases diffuse through the stomata

xerophytic plants

plants that live in dry habitats

adaptaion of xerophytic plants

rolled leaves to reduce water loss

sunken and fewer stomata( to prevent water loss grow slower because CO2 cannot diffuse in for photosynthesis)

reduced surface leaf area to reduce water loss

thicker cuticle to reduce water loss

pathway for gas exchange in insects

oxygen diffuses through spiracles into tracheae and into trachioles, fluid moves into to cell( due to low water potential of cell) after exercise

CO2 diffuses vice versa ( describe in exam ) maintaining diffusion concentration gradient

what is ventilation

moving air in and out of the lungs

structure of the human gas exchange system

trachea divided into two bronchi in each lung

bronchi divided into bronchioles in each lung

bronchioles are connected to tair sacs called alveoli

movement of oxygen from alveloar to blood

oxygen diffuse across the alveolar epithelium, and through the endothelium of capillary

features of the alvelar epithilium

moist

one cell thick

rich blood supply

large surface area

mechanism of breathing

external muscles contract and diaphragm relaxes and flattens

pressure in the thoraic cavity decreases as volume increases, so air moves down pressure gradient

internal muscles contract and and diaphragm contracts to move up

pressure increases, volume decreases in thoraic cavity. Air moves down the pressure gradient, air is drawn out

what happens when diaphragm is damaged

difficulty inhaling, reduced O2 when inhaling are less CO2 when exhaling

what does lung disease in mammals cause

increases surface area and increases diffusion pathway, less oxygen uptake, metabolic activities may not take place, and CO2 cannot diffuse across alveoli, less co2 exhaled, slower movement of CO2 concentration gradient is not maintained, more CO2 in the blood