Exchanging Substances Part 1- Gas Exchange Flashcards
What is breathing
Movement of air into and out of the lungs
What is respiration
Chemical reaction to release energy in the form of ATP
What does the rate of diffusion depend upon
Sa x conc. difference / diffusion distance
What substances do organsims need to exchange with their environment
Oxygen, co2
Glucose, amino acids, minerals, vitamins
Urea, ammonia
Heat
What are the key features of an effective exchange surface
High sa;v ratio
Short diffusion distance
Ability to maintain concentration gradient
Circulatory system
Describe gas exchange in single-cell organisms
Large sa;v ratio
Oxygen is absorbed by diffusion over the cell surface membrane
CO2 diffuses in opposite directions
Gas exchange in insects
How do they reduce water loss
Waterproof coating over their body - their exoskeleton is covered
Small sa;v ratio - area in which water is lost is reduced
Gas exchange in insects
Desicbe how air enters
Air enters through pores in their outer surface of their abdomen called spiracles
They open and close by valve
When they open water vapour evaporates
Gas exchange in insects
How does gas move in and out of the tracheal system
When oxygen is used- the concentration towards the en dot the tracheoles falls
This creates a diffusion gradient that diffuses into cell
CO2 is produced creating a diffusion gradient in the opposite direction
- this causes co2 to diffusion along the tracheoles and tracheae into the atmosphere
Contraction of muscle squeezes the trachea enabling mass movement of gas
Gas exchange in insects
Why are the end of the tracheoles filled with water
During activity, muscle cells anaerobically respire and produce lactate
Lactate is soluble and reduces the water potential of the muscle cells
Water moves into the cells by osmosis and more air is drawn in
What are the adaptations of gas exchange in insects
Tracheoles have thin walls- short diffusion distance
Highly branched - short diffusion distance e
Tracheae provides tubes full of air - fast diffusion
Fluid in the end
What are the features of gills
4 gills on either side of their head
Each gill is separated by a gill slit
Gill rakes protect the gills from food entry
Gills are covered with an operculum
What are gills good for for gas exchange
Provid enlarge sa
Gill filaments - series of flat projection at right angles to filaments called lamellae
Vast capillary network - good blood supply
Good vascular supply - short diffusion distance, conc. gradient maintained
Permeable membrane - gases to diffuse
Describe the counter current exchange in fish
Water an dblood flow in opposite directions
Diffusion/ conc. gradient maintained along length of filament/ lamellae
Prevents equilibrium being reached
Blood always passing water with higher o2 concentration
How are different plants adapted for efficient gas exchange
Thicker leafs - lower sa;v - prevent loss of water
Thicker waxy cuticle
Sunken stomata - traps most air next to leaf - reduces water potential radiant
(+ spines, hairs)
Deep roots, shallow lots
What is ventilation
Air is constantly being moved in and out of the mounts
What is inspiration (inhalation)
When the air pressure of the atmosphere is greater than the air pressure inside lungs
Active
What is expiration (exhalation )
Air pressure in lungs is greater than that of the atmosphere
What happens during inhalation
Diaphragm contracts and flattens
Ribcage moves up and out
Internal intercostal muscle contracts
Increases volume in thorax
Resulting is lowering ai rpressure (atmospheric pressure in high than thorax
Reduced pressure causes air to flow into our lungs
What happens during exhalation
Diaphragm relaxes, forms a dome shape
Ribcage moves down and in
Internal intercostal muscles contract
External intercostal muscles relax
Volum eof thorax decreases (pressure in thorax is higher than atmosphere)
Increases lung air pressure
Forcing air out of lungs
Describe and explain one feature of the alveolar epithelium that makes the epithelium well adapted as a surface for gas exchange. Do not refer to surface area or moisture in your answer.
Flattens cells - reduces diffusion distance
Permeable - allow diffusion for o2/co2
Describe and explain the mechanism that causes lungs to fill with air
Diaphragm contracts
External intercostal muscles contact
Pressure decreases
Air moves down pressure gradient
Air enters from higher atmospheric pressure
The adult damselfly uses a tracheal system for gas exchange.
Explain three ways in which an insect’s tracheal system is adapted for efficient gas exchange.
Tracheoles have thin walls so short diffusion distance to cells;
Highly branched / large number of tracheoles so short diffusion distance to cells;
Highly branched / large number of tracheoles so large surface area (for gas exchange):
Trachee provide tubes full of air so fast diffusion (into insect tissues):
Fluid in the end of the tracheoles that moves out (into tissues) during exercise so faster diffusion through the air to the gas exchange surface;
OR
Fluid in the end of the tracheoles that moves out (into tissues) during exercise so larger surface area (for gas exchange);
Body can be moved (by muscles) to move air so maintains diffusion / concentration gradient for oxygen / carbon dioxide;
