AS biology Exchange and transport flashcards


Flashcards on AS biology Exchange and transport flashcards, created by jenna.ridley on 24/05/2014.
Flashcards by jenna.ridley, updated more than 1 year ago
Created by jenna.ridley about 10 years ago

Resource summary

Question Answer
Name some features of an exchange surface that allow efficient diffusion? Thin Partially permeable Movement of the internal and external medium Large surface area to volume ratio
How does gas exchange take place in an insect Gases enter through spiracles on the surface of an insect. They then travel along trachea that are a network of tubes these subdivide into tracheoles that supply the tissues of the insect. The gases move in and out through a concentration gradient and through the process of ventilation
What two adaptations do insects have to prevent excessive water loss? Water proof coverings Small surface area to volume ratio
Describe the structures in a fish that are used in the gas exchange system? Fish have gills that are located behind the operculum of the head. These are made up of gill filaments that have gill lamella at right angles to increase the surface area for gas exchange. Water flows over the gills in gas exchange.
What type of exchange system do fish use and explain why? Counter current exchange system. This is to ensure a constant rate of diffusion. It ensures that water with a high concentration of oxygen always meets blood with a high concentration of oxygen too meaning that diffusion is always around 80%. It also means less energy is required reversing the water like the double circulatory system in humans.
What structures in leaves control the rate of gas exchange and also water loss? Stomata
Name the features of a transport system such as humans? Internal network of vessels to carry the medium.( veins, arteries and capillaries) A medium to carry the materials (blood) A mechanism for moving the medium (heart) A mechanism for controlling the flow in one direction (valves) A means of controlling the flow to suit the changing needs of different parts of an organism.
Why do mammals have a double circulatory system? To increase the pressure of blood retuning from the lungs so it can be pumped to the extremities of the body.
What is tissue fluid made up of? Amino acids Fatty acids glucose salts oxygen
What forces tissue fluid out of the blood plasma and what remains after? Hydrostatic pressure when the blood enters the capillaries forces tissue fluid out. Plasma proteins remain in the capillaries because of ultrafiltration
What other system returns tissue fluid to the circulatory system? Lymphatic system
Name the two methods in which water can move through the root Apoplastic pathway Symplastic pathway
Why does water enter the xylem and what pressure does this create? Active transport of mineral ions and salts into the xylem lowers its water potential so water enters by osmosis, this creates root pressure
Name 4 factors that can affect transpiration? Light Temperature Humidity Movement of air
Name some adaptations of a xerophytes plant? Thick cuticle Rolling of the leaves Small surface area to volume ratio Stomata in the pits or grooves Hairy leaves
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