thermoregulation 2 Flashcards
T tolerance curve
each animal species has its own unique T curve
can be different at different life cycles
acclimation
survivorship of T extremes affected by:
gene expression - chaperone proteins (heat shock proteins)
protein synthesis
adequate o2
response to sub zero T
super cooling water
directing ice crystal formation
behavioral changes
insects in sub zero T
either tolerate freezing or develop mechanism to avoid danger
migration, freeze tolerant, or freeze avoidant
freezing response
reduction in gas diffusion
reduction in enzyme function - Q10
structural disruption of enzyme
mechanical disruption of cell enzymes
osmotic dehydration due to freezing
ice formation response
water crystallization in geometric form
below oC without ice = supercooled
non-colligative properties
depends on the number of solutes and their chemical properties
sugar, Na+, K+
colligative properties
dependent on the number but not the chemical or physical properties of the solutes
reduction of vapor pressure, freezing point depression, boiling point elevation
glycerol
forms strong h-bonds with water, preventing ice formation
antifreeze proteins
strong non-colligative properties
need much less than ethylene glycol
v little osmotic effects
bind directly to ice crystals
prevents further ice formation
seeding ice crystals
some animals allow for ice crystal formation outside cells and limit crystal size
aquatic inverts
limit water movement
ectotherm genetic response
cold temps - increase mitochondrial density; increase cytochrome C-oxidase (CCO)
chaperone proteins
correct protein folding requires help
protects against denaturation
function as foldases or holdases
torpor
suspension of T regulation to save energy in extreme T
torpor choices
migrate
adapt
