Adaptations of Gas Exchange Surfaces Flashcards
Effective exchange surfaces in organisms have…? (3 things)
a large surface area
short diffusion distance
maintained concentration gradient
What is chlamydomomas and give 3 features
A single celled organism that is found in fresh water ponds. It is spherical in shape and has a diameter of 20um. Oxygen can diffuse across the cell wall and cell surface membrane.
Is diffusion an efficient exchange mechanism for chlamydomomas?
yes
What type of skeleton do all insects have and what coating does it have, what is the coating impermeable to?
A rigid exoskeleton with a waxy coating that is impermeable to gases
Where does insects breathing system deliver oxygen directly to in their bodies?
all the organs and tissues
What is a spiracle and what is its function?
An opening in the exoskeleton of an insect which has valves. It allows air to enter the insect and flow into the system of tracheae.
Why are the spiracles closed most of the time?
To reduce water loss
What are tracheae?
Tubes within the insect breathing system which lead to tracheoles.
Why do tracheae walls have reinforcements that keep them open?
Because the air pressure inside them fluctuates
Why can a concentration gradient be created in insects?
As oxygen is used by respiring tissues allowing more to move in through the spiracles by diffusion.
What happens to the carbon dioxide produced by the respiring tissues in insects?
Moves out through the spiracles down a concentration gradient
What do very active, flying insects need?
a more rapid supply / intake of oxygen
How do insects create a mass flow of air into the tracheal system?
closing the spiracles, using muscles to create a pumping movement for ventilation
What happens during flight of an insect?
The production of lactate in the respiring muscles lowers the water potential of muscle cells. Water found at the narrow ends of the tracheoles is then drawn into the respiring muscle by osmosis. This allows gases to diffuse across more quickly.
A given volume of our air contains how many times more oxygen than the same volume of water?
30
What are fish adapted to do?
directly extract oxygen from water
What is the structure of fish gills in bony fish?
series of gills on each side of the head, each gill arch is attached to two stacks of filaments, on the surface of each filament there are rows of lamellae, the lamellae surface consists of a single layer of flattened cells that cover a vast network of capillaries.
What does the capillary system within the lamellae ensure?
that the blood flow is in the opposite direction to the flow of water - it is a counter-current system
What does the counter current system ensure?
the concentration gradient is maintained along the whole length of the capillary
Where is the water with the lowest oxygen concentration found?
adjacent to the most deoxygenated blood
In order to carry out photosynthesis, plants must have an adequate supply of what?
carbon dioxide
How have leaves evolved?
They have adaptations to aid the uptake of carbon dioxide
What are the components of a leaf? (7)
waterproof cuticle, upper epidermis, palisade mesophyll layer, spongy mesophyll layer, stomata, guard cells, lower epidermis
What is the upper epidermis?
a layer of tightly packed cells
what is the palisade mesophyll layer?
a layer of elongated cells containing chloroplasts
what is the spongy mesophyll layer?
a layer of cells that contains an extensive network of air spaces
What is the stomata?
pores (usually) on the underside of the leaf which allows air to enter
What are the guard cells?
pairs of cells that control opening and closing of stomata
What is the lower epidermis?
a layer of tightly packed cells
What happens when the guard cells are turgid?
the stomata remains open allowing air to enter the leaf
What do the air spaces within the spongy mesophyll layer allow?
CO2 to rapidly diffuse into cells
What cells quickly use up CO2 in leaves, what is it used for?
Cells containing chloroplasts, used for photosynthesis
What is maintained by CO2 being used up quickly in photosynthesis?
A concentration gradient
Why is no active ventilation required in leaves?
As the thinnest of the plant tissues and the presence of stomata help to create a short diffusion pathway
