5.1 - communication,homeostasis,energy Flashcards
what conditions are required inside cells for enzymes to function properly
suitable temp
suitable ph
freedom from toxins ad excess inhibitors
aq solutions that keep substrates and products in a solution
wht chnages an organisms external environment
temp
food
water
danger
stimulus
change in internal or external env of an organism
response
way in which an organism, changes its behaviour or physiology in reaction to the stimulus
why is a a good communication system needed
to
enable specific and rapid communication between cells in order to respond to changes in the environment and coordinate the activities of different organs
short term and long term communication
what are the two major systems of communictions
neuronal
hormonal
def of homeostasis
the maintenance of the internal environment in a constant state despite the external changes
5 variables that need to be kept constant
body temp
blood glucose conc
water potential in blood
blood pressure
co2 conc
sensory receptor cells
detect and deviation from set point
effector cells
brings about necessary change to return system to set point
neg feedback loop of temp
body temp at 37
temp inc
skin detects change
nerv system informs brain
sweat reacts to reverse change return to 37
positive feedback loop
giving birth
no pressure on cervix
pressure on cervix
stretch receptors detect pressure
hypothalamus releases oxytocin
oxytocin inc uterine conc
ectothermic organisms
Relies on external sources of heat
Endotherms
Use internal sources of heat
Advantages and disadvantages of being ectothermic
Advantages
Use less food for respiration
Can survive long periods without eating.
Greater proportion of energy from food can be used for growth.
Disadvantages.
Less active in cooler temperatures which means grades of predation.
May not be capable of activity in the water.
More at risk from climate change 
