Chapter 8 Flashcards
Describe the need to transport substances into and out of a range of organisms
Oxygen and Carbon dioxide for respiration and photosynthesis.
Water for plants and lungs
Dissolved food molecules for digestion and energy
Mineral ions in the blood and for plants via osmosis
Urea to get transported to kidneys
What does the blood transport
Disolved substances
Explain the need for exchange surfaces and a transport system in multi cellular organisms
As size of an organism increases, its surface area to volume ratio decreases. Therefore rate of diffusion wont be fast enough for cells to function. Large multi cellular organisms therefore cannot rely on diffusion alone to supply their cells with substances such as food, oxygen and waste products. Large multi cellular organisms require specialized transport systems.
Eg- the heart uses blood vessels to transport these substances around the body
How are alveoli adapted for gas exchange by diffusion between air in the lungs and blood in the capillaries.
They give lugs a large surface area
They have moist, thin walls.
They have lots of tiny blood vessels called capillaries.
What factors affect the rate of diffusion,
surface area, concentration gradient and diffusion distance.
How does concentration gradient effect rate of diffusion
rate of diffusion will increase when concentration gradient increases
How does Distance effect rate of diffusion
Rate of diffusion increases when distance is decreased
How to calculate rate of diffusion using Flicks law
Rate of diffusion= surface area x concentration difference / thickness of membrance
Explain how the structure of the blood is related to its function - RED BLOOD CELLS (erythrocytes)
The red blood cells transport oxygen, it has a bi concave shape which increases surface area- increases rate of diffusion. Doesn’t have a nucleus- more room for haemoglobin. Small size to pass through narrow capillaries.
Explain how the structure of the blood is related to its function- WHITE BLOOD CELLS (Phagocytes and lymphocytes)
White blood cells protect against disease.
They are adapted to change shape which allowes them to wrap around microbes in body and ingest them. They produce antibodies to destroy pathogens and produce antitoxins that neutralize the toxins released by pathogens.
Explain how the structure of the blood is related to its function- PLASMA
Plasma transports dissolved substances around the body including- Hormones, antibodies, nutrients and waste substance. Its a good solvent
Explain how the structure of the blood is related to its function- PLATELETS
Platelets help the blood to clot by clumping together and prevents bleeding, they are small fragments of cells and dont posses a nucleus
How is the structure of the blood vessel- ARTERY adapted to its function
Thick, elastic, muscular walls to withstand pressure so it can carry blood away from heart at high pressure.
How is the structure of the blood vessel- Capillary- adapted to its function
Thin permeable walls to allow exchange of materials between blood and tissues.
How is the structure of the blood vessel- vein - adapted to its function
Large diameter to offer least flow resistance. Valves to prevent black flow so it can return low pressure blood to the heart.