Topic 8 - Transport in animals Flashcards
Which substances need to be transported in and out of animals
Oxygen, carbon dioxide, water, dissolved food molecules, mineral ions and urea
Explain the need for exchange surfaces and transport systems and the relationship with surface area:volume ratio
As organisms get bigger, their surface area to volume ratio gets smaller
Consequently they cant rely on diffusion
This means they need exchange surfaces and transport systems
What is oxygen’s site of exchange and reason for exchange
Alveoli in lungs
Needed for respiration
What is carbon dioxide’s site of exchange and reason for exchange
Alveoli in lungs
Waste product of metabolism
What is water’s site of exchange and reason for exchange
Nephrons in kidney
Needed for cells to function
What is dissolved food molecules site of exchange and reason for exchange
Small intestine
Needed for respiration
What is mineral ions site of exchange and reason for exchange
Small intestine
Needed for cells to function
What is urea’s site of exchange and reason for exchange
Nephrons in kidney
Waste product of metabolism
How are some organs adapted for exchange
They’re adapted to make exchange efficient
Lungs adapted to exchange gases
Small intestine adapted to exchange solutes
Explain how alveoli are adapted for gas exchange
Adapted by diffusion between air and lungs and blood in the capillaries
Millions of alveoli (air sacs) adapted to create large surface area for gas diffusion
Each closely associated with a capillary. Walls one cell thick, minimising diffusion distance
Describe the factors affecting the rate of diffusion
+ surface area (eg alveoli in lungs)
shorter distance for diffusion (eg surfaces one cell thick)
maintenance of a high concentration gradient (eg animals efficient blood supply, ventilated lungs)
how do you calculate the rate of diffusion
FICKS LAW:
rate of diffusion α surface area × concentration difference / thickness of membrane
explain how the structures in blood are related to function
PLASMA - liquid, carries blood cells through vessels
WHITE BLOOD CELLS - larger than red, has nucleus, immune system attacks pathogens
PLATELETS - causes blood to clot when vessel damaged. clot blocks wound prevents pathogens entering
RED BLOOD CELLS - haemoglobin (carries oxygen), bioconcave shape - larger surface area, easier for oxygen to diffuse in & out, no nucleus more room for oxygen
Explain how the structure of the blood vessels is related to their function
VEINS - large space, thinner wall than artery, valves stop blood flowing backward so returns to heart
ARTERIES - carry oxygenated blood away from heart to body
CAPILLARIES - exchange materials with body tissues, capillary only one cell wide, wall one cell thick
Arterues take blood Away, veINs bring it back IN to the heart
Explain how the structure of the heart is related to its function
VALVES prevent backflow (backward blood flow)
PULMONARY ARTERY carries deoxygenated blood, heart —> lungs
AORTA carries oxygenated blood, heart —> body
PULMONARY VEIN brings oxygenated blood, lungs —> heart
VENA CAVA brings deoxygenated blood, body —> heart
LEFT VENTRICLE muscle wall thicker than right, bc it pushes blood round body
explain how blood moves around the body
- enters atria
- atria contract, blood into ventricles
- ventricles contract, blood into arteries
- blood through arteries to organs and returns to heart through veins
describe cellular respiration
EXOTHERMIC, release energy for metabolic processes, including aerobic, anaerobic respiration
describe aerobic respiration
series of chemical reactions, inside mitochondria. glucose completely broken down
exothermic - releases energy used for building larger molecules from smaller, enable muscle contraction, maintain body temp
glucose + oxygen —> carbon dioxide + water
describe anaerobic respiration
respiration that occurs in absence of oxygen, doesnt occur in mitochondria
part breakdown of glucose due to lactic acid
produces lactic acid, extra oxygen required to oxidise to co2 and water after exercise
less energy released than aerobic
explain advantages and disadvantages of anaerobic respiration
ADVANTAGES:
- useful for muscle cells, can replace aerobic when energy is needed for muscles to contract
- respiration continues in organisms w little/no oxygen
DISADVANTAGES:
- releases less energy
- lactic acid not removed from body, builds up in muscle and blood must be broken down
how do you calculate cardiac output
cardiac output = stroke volume × heart rate
explain the function of soda lime in the respiration practical
absorbs co2 produced by seeds, so doesnt affect movement of liquid blob
explain why the liquid blob moves during the respiration experiment
oxygen is absorbed from surrounding air by germinating seeds.
reduces volume of air in container, so blob moves towards container
explain how a respirometer could be used to measure rate of respiration of the seeds
distance liquid blob moves over time could be measured
rate calculated by dividing distance by time
describe the controls for the respiration experiment
- TEMPERATURE
- for something other than the study organisms affecting gas volume (eg same volume of substances)
