10.Regulation in plants and animal cells Flashcards
how does water get into a plant
Osmosis has occurred. Water has moved from the hypotonic environment in the soil surrounding the root hair cell, through the partially permeable plasma membrane of the root hair cell, to the hypertonic cytosol of the root hair cell. The root hair cell becomes turgid.
how does water get out of a plant
after moving up the xylem, plants lose water by transpiration
use of water in plants
photosynthesis
hydrolysis
maintain turgidity
what hormone controls water loss
abscisic acid
how are stomata closed
-stimulus eg decreased water levels
-abscisic acid hormone is released
-abscisic and binds to specific guard cell receptors
-chloride ions and potassium ions are pumped out of guard cells
-guard cells cytosol is now hypotonic and the environment surrounding is hypertonic
-water moves out of guard cell
-guard cell becomes flaccid
-stomata is closed
when would stomata close and open
Close in response to:
low CO2 concentration
low light intensity
low water availability
open in response to:
high CO2 concentration
high light intensity
high water availability
how are stomata opened
-stimulus eg increased light intensity
-triggers specific receptor
-chloride ions and potassium ions are pumped into guard cells
-the cytosol of guard cell is now hypertonic and surrounding environment is hypotonic
-water follows and moves into guard cells
-guard cells become turgid
-stomata open
define homeostasis
the maintenance of a constant internal environment, within narrow limits, in the face of external change
what is negative feedback
when response opposes the original stimulus
normal body temperature
37 degrees celsius
what is metabolism
all of the chemical reactions in your body or cell
receptor for maintaining body temperature (thermoregulation)
thermoregulatory centre in hypothalamus
coordinator for maintaining body temperature (thermoregulation)
thermoregulatory centre in hypothalamus
what responses does your body make when its too cold
-shivering
-vasoconstriction
-goosebumps/piloerection
-huddle
-increased metabolism
-behaviours-jumping, physical activity
how can sweat glands help when body temperature decreases
sweat glands stop releasing sweat, decreasing heat loss due to evaporation and increasing body temperature
how can arteries help when body temperature decrease
blood vessels/arteries vasoconstrict, decreasing blood flow to surface of body, decreasing heat loss by radiation
how can shivering help when body temperature decreases
shivering (rapid muscle contractions) increase of excess heat produced, increase body temperature
how can piloerection help when body temperature decreases
goosebumps, more air trapped between hairs, increasing insulation
how can thyroid gland help when body temperature decreases
thyroid gland can increase thyroxine production, increasing metabolism (chemical reactions), increased heat produced as by-product, increasing body temperature
what responses does your body make when its too hot
-sweating
-vasodilation
-reduced metabolism
-behaviours- reduce physical activity, showering/swimming, increase SA:V
how can sweat glands help when body temperature increases
sweat glands produce more sweat, increasing heat loss via evaporation
how can arteries help when body temperature increases
blood vessels/arteries vasodilate, increasing blood flow to surface of body, increasing heat loss by radiation
how can thyroid gland help when body temperature increases
thyroid stops releasing thyroxine, slowing metabolism, decreasing chemical reactions, decreasing heat being produced as byproduct and decreasing body temperature
what is glucose needed for by all cells
needed for aerobic cellular respiration
receptor for blood glucose levels
pancreas
coordinator for blood glucose levels
Pancreas
what cells produce insulin
beta cells
what cells produce glucagon
alpha cells
what happens when blood glucose levels are high
beta cells release insulin, that causes glucose to be stored as glycogen in liver and muscle cells
what happens when blood glucose levels are low
alpha cells release glucagon, that causes glycogen stores to be broken down into glucose in liver and muscle cells
define osmoregulation
osmoregulation is the process of maintaining a stable water and salt content in the blood
receptor for osmoregulation
osmoreceptors
coordinator for osmoregulation
hypothalamus
effector for osmoregulation
pituitary gland
effectors for maintaining BGL
beta or alpha cells of the pancreas
how does the body respond to low water levels
-low water levels (dehydration)
-increase ADH released
-increased permeability of convoluted tubules and collecting ducts of nephrons in kidneys
-increased water absorption (back into the bloodstream)
-more concentrated urine is produced (more water retained)
how does the body respond to high water levels
-high water levels (hydrated)
-decreased ADH released
-decreased permeability of convoluted tubules and collecting ducts of the nephrons in the kidney
-decreased water absorption
-diluted urine produced (more water lost)
what is a stimuli
change in environment
what is a hormone
chemical messenger
