Key Area 3 - Metabolic Rate Flashcards
What is the definition of metabolic rate?
Metabolic rate is the quantity of energy consumed by an organism per unit of time.
What is the general trend with respect to metabolic rate and size of organisms?
Generally the larger the organism the greater the metabolic rate.
List 3 ways that metabolic rate can be measured.
Oxygen consumption per unit time
Carbon dioxide production per unit time
Energy production (e.g. heat) per unit time
This can be done by using respirometers, oxygen probes, carbon dioxide probes and calorimeters.
How is oxygen consumption per unit time measured?
Oxygen probe or respirometer.
How is carbon dioxide production per unit time measured?
Carbon dioxide probe or respirometer.
What is a respirometer?
A respirometer is an experimental set-up used to measure the rate of oxygen consumption over time.
What is a calorimeter?
A calorimeter is a device used to measure metabolic rate by determining energy production as heat over time.
What happens to an organism’s rate of oxygen consumption as their metabolic rate increases?
As an organism’s metabolic rate increases so does its rates of aerobic respiration and oxygen consumption. This means organisms with a high metabolic rate need to have a more efficient transport system to deliver oxygen to the cells.
Explain why organisms with high metabolic rates need efficient transport systems.
Oxygen needs to be delivered to cells in an efficient way to maintain a high metabolic rate. This is achieved through transport systems like respiratory and circulatory systems.
Describe the circulatory systems found in mammals and birds.
Birds and mammals have a complete double circulatory system consisting of two atria and two ventricles.
How does a double circulatory system enable higher metabolic rates to be maintained?
There is no mixing of oxygenated and deoxygenated blood.
Oxygenated blood can be pumped out at a higher pressure.
Describe the circulatory systems found in amphibians and reptiles.
Amphibians and most reptiles have an incomplete double circulatory system consisting of two atria and one ventricle. There is mixing of the oxygenated and deoxygenated blood in the ventricle.
Describe the circulatory system found in fish.
Fish have a single circulatory system consisting of one atrium and one ventricle.
Place the following in order of metabolic rate (highest to lowest).
Fish
Birds and mammals
Amphibians and reptiles.
Highest ————————–> Lowest
Birds ——> Amphibians ——> Fish
and and
Mammals Reptiles
