exchange and transport Flashcards
what is the general trend between an organisms volume and surface area
as aorganisms increase in volume surface area decreases
explain how single celled organisms exhcnage substances
simple diffusion as the large SA:V ratio is large and therefore a short diffusion pathwat
explain why large organsism need adaptations for exhcnage of substances
the diffusion pathway is too large for efficient gas exchange to occur as there is a smaller SA:V ratio for absorbption of nutrients and exchnage of gases O2 and CO2
what is metabolic rate
the amount of energy expended by that organism within a given period
what is the basal metabolic rate
the metabolic rate of an organism when at rest
how can metabolic rate be measured
oxygen consumption
carbon dioxide production
heat production
what is ficks law
rate of diffusion= (surface area x concentration difference) / thickness of membrane
how are insects adapted for gas exchange
They have spiracles that lead into a large network of trachea and tracheoles which run to muscle fibres.
A concentration gradeint is created as oxygen is used by the tissue fibres allowing more to move in through the spiracles.
what do very active insects do to get the supply of oxygen they demand if they cant get it through spiracles
they close the spiracles and use muscles to create a pumping movement for ventilation
what does anaerobic repsiration cause to happen in an insects gas exchnage system
produces lactic acid which lowers the water potential of the muscle fibres causing water at the end of the tracheoles to move into the muscle cells by osmosis and therefore diffusion of oxygen is made easier by the diffusion pathway being made shorter and therefore aerobic respiration can start again
how are fish adapted for gas exchange
series of gills on each side of the head that have stacks of filaments and on the surface of the filaments are rows of lamellae, Blood flow and water flow are in oppsite direction in a countercurrent system maintaining gas exchnage as theres a constant gradient
how are plants adapted to gas exchange
the guard cells can go turgid and the stomata remains open allowing air to enter the leaf and rapidly diffuse across the air spaces in the spongy mesohpyll and once the CO2 reaches photosynthesising tissues it is immediately used up to maintain the concentration gradient
how do insect counterbalance water loss
posses a waterproof exoskeleton that prevents water loss as it has a waxy coating which makes gas exchange difficult and stop
how to plants counterbalance waterloss like cacti and maram grass
cacti: thick cuticle, shalloe deep roots, leaves have become spines that can no longer photosynthesise
maram grass: leaves can roll up reducing exposure to wind protecting the stomata, exposed surface has a thick cuticle and no stomata, the inner surface of the leaf possesses a large amount of hairs
how are alveoli adapted
short diffusion pathway: walls are one cell thick, flattened
maintaining concentration gradient: constant blood flow
large surface area: large number of them in the lungs
describe what happens in inspiration
external intercostal mucles contract, the diaphram contracts and goes flat the ribs go out and up leading to an increase in volume in the thorax which causes a lower pressure which causes a pressure gradient so air from outside rushes into the thorax
describe what happens in expiration
internal intercostal muscles contract pulling the ribs down and in and the diaphram relaxes and becomes domed shaped so the volume in the thorax decreases and so the pressure increases so air is forced out of the lungs
what is the equation for pulmonary ventilation rate
PVR= tidal volume x breathing rate
what is the need for a circulatory system
so that the large organisms can supply their cells with desired substances
what is the structure of haemoglobin
globular protein made up of four polypeptide chains held together by disulphide bonds arranged so that their hydrophillic R groups points outwards and be soluble in water
The haem group contains an iron (II) ions which can reversibly with oxygen forming oxyhaemoglobin
Each haemoglobin with four haem groups can therfore carry 4 O2 molecules
explain the oxygen dissociation curve
The far left of the graph is when the haem groups are all unbound and therefore the affininty is at its lowest
As the partial pressure increases and the saturation of haemoglobin increases the affininty increases as the strcuture of haemoglobin gets looser and the shape of it changes
As the haemoglobun gets more and more saturated there is a levelling off of the curve as it takes longer for the 4th oxygen to bind as there is a shortage of remaining binding sites
what is the Bohr shift and explain it
changes in teh dissociation curve as a reult of CO2 levels are known as the Bohr shift effect
when the partial pressyre of CO2 in the blood is gigh the haemoglobins affninity for oxygen is reduced due to the CO2 lowering the pH of the blood as the CO2 binds with the water to from carbonic acid
on the dissociation cirve the curve shifts to the right when CO2 levels increase
what is the equation for cardiac output
cardiac output= heart rate x stroke volume
how do animals adapt to high altitudes
the partial pressure in oxyven is lower at higher altitudes and therfore have haemoglobin that is adapted to these conditions
For example, llamas have haemoglobin that binds much more readily in oxygenn which is important as it allows them to obtain sufficient level of oxygen saturation in thier blood when the partial pressure of oxygen is low
how are foetus’s adapted to get sufficient oxygen into the body
they have higher affinity for oxygen than adults and this is vital as it allows foetus to obtain oxygen from its mothers blood at the placenta
what is the basic structure of the heart
the heart is divided into four chambers the top two being the atris and the bottom two being the ventricles
the left and rught sides are seperated by a wall called the septum
there are two blood vessels taking bloof to the heart and they are the vena cava and the pulmonary vein
there are two blood vessel taking blood away from the heart and these are called the aorta and the pulmonary artery
explain the layout of the valves in the heart
the right hand side of the hearts right atrium and ventricle are seperated by the tricuspid valve
the left hand sides atrium and ventricle are seperated by the bicuspid valve
the left ventricle and the aorta and seperated by the aortic valve