Metabolism and adverse conditions Flashcards
Which abiotic factors can affect an organisms metabolic rate?
Temperature, salinity, pH
What is a conformer?
An organism which cannot maintain its metabolic rate through physiological mechanisms.
What is a conformers internal environment dependent on?
Its external environment.
What is an advantage of being a conformer?
Low metabolic costs
What are the disadvantages of being a conformer?
Narrow range of ecological niches, cannot tolerate dramatic changes to environment.
What is a regulator?
An organism which can maintain a steady internal environment by using physiological mechanisms.
What is an advantage of being a regulator?
Can occupy a wide range of ecological niches.
What is a disadvantage of being a regulator?
Requires energy to maintain homeostasis.
What is homeostasis?
Maintaining steady conditions within an organism.
What is negative feedback control?
Any change in a condition from the optimum is detected by receptors that switch on a corrective mechanism to restore the conditions to normal. The corrective mechanism is then switched off.
What is a receptor?
Cells which detect changes in the environment and send signals to effectors.
What is an effector?
Parts of the body that respond to messages send by receptors.
Which part of the brain is described as the temperature monitoring centre?
Hypothalamus
What are the effectors involved in thermoregulation?
Sweat glands, skin arterioles, hair erector muscles, skeletal muscles.
How are signals sent from the hypothalamus to the effectors in thermoregulation?
By nerve impulses
What happens in mammals as a response to increased temperature?
Increased sweat production, vasodilation, hairs lowered
What happens in mammals as a response to decreased temperature?
Hair erector muscles contract, vasoconstriction, decreased sweat production, shivering
How does sweating lead to a decrease in body temperature?
The body evaporates the water from the skin which lowers body temperature by convection.
What is vasodilation?
When the skin arterioles widen increasing blood flow to the surface of the skin increasing heat loss by radiation.
What is vasoconstriction?
When the skin arterioles narrow reducing blood flow to the surface of the skin and reducing heat loss by radiation.
How do hairs on your body standing up increase temperature?
They trap a layer of insulating air reducing heat loss
What is an advantage to maintaining a constant body temperature?
To ensure the optimum temperature for enzymes to maintain a high metabolic rate.
What is thermoregulation?
Use of negative feedback control to regulate body temperature in mammals
Other than enzyme activity why else is temperature important?
It affects diffusion rates, diffusion of oxygen and glucose into cells for respiration is faster in warmer temperatures to maintain high metabolic rates.
