lec 14

Question 1

endotherms and ecotherms alike like to chill at around 27 degrees C. why is that?

Answer 1

probably the optimized point for which prots/enzymes can work

Question 2

when we plot body temp against metabolism, we find a largely exponential relationship. does this go on forever? towards either end of the extreme, how are animals doing?

Answer 2

the relationship goes exponentially, but eventually there has to be a dropoff since the body can only take so much

towards lower ends of the extreme, animals for the most part do alright; towards higher ends of the extreme, incremental increases have increasingly drastic effects

Question 3

ok so them lizards that acclimate to diff temps. what do they do (pic on slide 11 for reference)

Answer 3

so the lizards will start at high temp (we’ll say 35 degrees). we put them in lower temps (15 degrees). they will acclimate down to 15 degrees, but actually keep their metabolism a little higher than they normally would at 15 degrees. the inverse will occur if u bring them back up to 35 degrees: their metabolism will be lower than it would be at 35 degrees. [double check dis]

Question 4

abundance of mitochondria per unit of muscle vs activity of cytochrome oxidase per unit of mito prot. which is qualitative and which is quantitative

Answer 4

our measly human words cannot fathom the complexity of the humble trout

u can really make an argument for either: the key is that quantitative incr #, while qualitative incr the effectiveness

Question 5

to survive colder temps, what do animals have to do (a simple action)?

Answer 5

eat more to maintain metabolism

Question 6

a generalized performance curve when plotting performance against temp consists of:
- peak
- pejus range
- high critical temp
- death
- denaturation
explain each of these processes

Answer 6

peak is peak performance per temp - anything after decr performance

pejus range is where activity performance begins to fall off, but the animal survives - it just isn’t optimal

high critical temp is when shit starts to really fall apart, and the animal needs to start cutting its losses

death

denaturation is when proteins begin to fall apart

Question 7

at lower temps, cataracts begin to form in the lenses of animals, starting at about 0 degrees. what adaptations do some animals have to overcome this?

Answer 7

antarctic toothfish live in temperatures of about -2 at all times
have adapted different alpha crystallin prots, whose purpose is is maintaining structural function

Question 8

is enzyme affinity constant or not? there’s an argument for both sides

Answer 8

+ clearly we see a relationship between enzyme affinity and temperature, where at higher ranges enzyme affinity falls apart rapidly

• if u look across many species, we see that most animals stay within a certain enzyme affinity range. it can be argued that enzyme affinity is constant in the sense that all animals stay in body temp ranges that maintain a certain enzyme affinity

Question 9

what is the difference between stenothermal and eurythermal animals? how does this look for enzyme affinity?

Answer 9

stenothermal can tolerate a narrow range of environ temps, while eurythermal can tolerate a wide range of environ temps. predictable, steno- is quicker to drop enzyme affinity when brought out of its normal range

Question 10

if eurythermal animals can survive in wider ranges, why would anyone ever choose to be stenothermal?

Answer 10

at the extreme ranges eurythermal are more likely to survive. however, realistically, most animals dont hit the extremes – it can be costly to maintain these proteins if ur never gonna use them, so animals hedge their bets and sacrifice living at the extremes if they’re in relatively stable environments