Mass Transport Flashcards
Why is there a small increase in pressure and in rate of blood flow in the aorta and whys it important
Elastic recoil of the aorta walls
Smooths blood flow/maintains blood pressure
What is the relationship between surface area and volume
The larger the organism the smaller the surface area to volume ratio
As volume increases, surface area to volume ratio decreases
What is Fick’s law
Diffusion rate= Surface area x Concentration gradient / Diffusion distance
What makes a good gas exchange system
Large surface area
Large concentration gradient
Thin exchange surface
How do larger organisms combat having a small SA:VOL
Developed specialised gas exchange systems and surfaces which have adaptations to ensure the rapid diffusion of gases
Why are cells usually limited in size
As cell size increases (volume) its surface area to volume ratio decreases
Meaning it can’t exchange substances efficiently or get materials fast enough to carry out its function
Smaller cells are more effective at transferring materials
What are the ways insects balance gas exchange and water loss
Waterproof covering: Over their bodies surface (usually rigid outer skeleton (an exoskeleton) covered with a waterproof cuticle
Small SA:VOL: Minimise the area over which water is lost
Specialised gas exchange system (trachea): Specialised internal gas exchange surfaces to minimise water and heat loss wh
What are the parts if an insects gas exchange
Tracheal system:
Spiracle
Trachea
Tracheoles
What is the name of an insects gas exchange system
Tracheal system
What is the purpose of spiracles
Tiny pores which gas enters and leaves the insect through
They open and close to control water loss by evapouration
They open when carbon dioxide levels increase
What is the purpose of the trachea
Network of tubes supported by strengthened rings
Lined with chitin
Which stops the tubes collapsing under low pressure
Providing tubes full of air so that diffusion can occur fast
What is the purpose of tracheoles
Small tubes with thin walls so the diffusion distance is reduced
They extend throughout the body tissue
Highly branched so there is a large surface area
Gas exchange occurs at the end of the tracheoles
How does the movement of oxygen occur in insects
Oxygen enters the insect through spiracles and into the trachea
Oxygen diffuses through the trachea into the tracheoles
Oxygen is delivered directly to the respiring tissue where it is used in the mitochondria of aerobically respiring cells
Keeping the oxygen concentration lower and maintaining a concentration gradient
How does the movement of carbon dioxide occur in insects
Waste carbon dioxide from aerobic respiration delivered to tracheoles
Diffuses from tracheoles into trachea then moves to spiracles
Carbon dioxide leaves insects through spiracles
Explain ventilation
Movement of insects muscles in their abdomen creates a mass movement of air in and out of the trachea
This speeds up the rate of gaseous exchange
Also have small air sacs in their trachea
Muscles around the trachea contract and pump air into the sacs deeper into the trachea
How is an insects tracheal system adapted for efficient gas exchange
Tracheoles have thin walls so short diffusion distance to cells
Tracheoles highly branches/large number of tracheoles so a short diffusion distance to cells AND a large surface area or gas exchange
Trachea provides full tubes of air so fast diffusion into insect tissues
Fluid in the end of tracheoles that move out into tissue during exercise so faster diffusion through air to gas exchange surface
Body can be moved by muscles to move air so maintains a diffusion/concentration gradient for oxygen and carbon dioxide
How do insects get additional oxygen during flight
At rest water can build up in the tracheoles
During flight the insect may partly respire anaerobically and produce some lactate (lactic acid)
This lowers the water potential of muscle cells
As lactate builds up water passes via osmosis from the tracheoles into the muscle cells
This adaptation draws air into the tracheoles closer to muscle cells and therefore reduces the diffusion distance for oxygen when it is needed
Improve the quality of a scientific drawing
Don't use shading Only use single, continuous lines Add lables/annotation Don't cross label lines Add a scale bar/magnification
Explain abdominal pumping in insects
Causes an increased pressure in abdomen (trachea)
More oxygen enters muscles more quickly
So maintains greater diffusion gradient
Compare and contrast bony and cartilagenous fish
Cartiligenous fish have a skeleton made of only cartilage whereas bony fish have an internal skeleton made from bone
Cartilagenous fish do not have an opperculum whereas bony fish do have an opperculum
Cartilagenous fish have 5-7 gills whereas bony fish have 4 pairs of girls
Cartilagenous fish use concurrent flow to exchange gases whereas bony fish use counter-current flow
Explain inspiration in fish
The mouth opens
The opercula on both sides close
The floor of the mouth (buccal) cavity is lowered
The volume inside the buccal cavity increases
The pressure inside the buccal cavity decreases
Water flows into the buccal cavity down as the external pressure is higher than inside the mouth (some water moves over gills) down a pressure gradient
How are fish gills adapted for efficient gas exchange
Many gill lamellae provide a large surface area for faster diffusion of gas
Thin epithelium of lamellae so a short diffusion pathway between water and blood
Counter current flow means water flows over the gills in the opposite direction to the blood flow in capillaries which maintains the concentration gradient along entire length of gill
Oxygen diffuses from water into blood as always next to blood with a lower concentration of oxygen
Blood circulation replaces the blood saturated with oxygen
Ventilation mechanism replaces the water over the gill surface
Explain how a counter current ensures maximum oxygen passes into the blood
Water and blood flow in opposite directions
Blood always passing water with a higher concentration of oxygen
Diffusion/concentration gradient maintained throughout the length of the gill lamellae/filaments
(Equilibrium not reached)
Gill lamellae vs filaments
Lamellae are smaller than filaments
Lamellae are in the filaments
Counter current vs con current
Counter current: no equilibrium is reached because concentration gradient is maintained all along the whole length of the gill lamellae
Con current: only maintained along part of it
Counter current: almost all of the oxygen in the water diffuses into the blood
Con current: only 50%
Briefly outline how oxygen and carbon dioxide enters and leaves a fish
Water containing oxygen enters through the fish mouth
Passes through the gill lamellae on the gill filaments
Where most of the oxygen removed
Water containing little oxygen and lots of carbon dioxide leaves through the gill opening
Dicotyledonous plant definition
Flowering plant
Xerophytic plant definition
Live in dry/arid environments
List the structures of a leaf
Waxy cuticle Upper epidermis cells Palisade mesophyll cells Spongy mesophyll cells Sub stomatal air spaces Lower epidermis cells Guard cells Stomata
Waxy cuticle
Water proof coat to reduce water loss through evaporation
Upper epidermis cells
Usually a single layer of lightly packed cells on the top and bottom of leaves
Palisade mesophyll cells
Where most photosynthesis occurs
Contain many chloroplast
Found towards the upper surface of leaf
Column shaped and packed closely together
Spongy mesophyll cells
Loosely packed for efficient gas exchange
Covered in a thing layer of water for gases to dissolve in as they move in an out of the cell
Lower epidermis
Usually a single layer of cells
Contain stomata and guard cells in between some cells
